SemaChecking.cpp revision d1b47bf17fde73fac67d8664bd65273742c00ecd
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)//===--- SemaChecking.cpp - Extra Semantic Checking -----------------------===// 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// The LLVM Compiler Infrastructure 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This file is distributed under the University of Illinois Open Source 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// License. See LICENSE.TXT for details. 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 87dbb3d5cf0c15f500944d211057644d6a2f37371Ben Murdoch//===----------------------------------------------------------------------===// 93551c9c881056c480085172ff9840cab31610854Torne (Richard Coles)// 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// This file implements extra semantic analysis beyond what is enforced 11c2e0dbddbe15c98d52c4786dac06cb8952a8ae6dTorne (Richard Coles)// by the C type system. 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// 13a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7Torne (Richard Coles)//===----------------------------------------------------------------------===// 14a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7Torne (Richard Coles) 15f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)#include "Sema.h" 16f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)#include "clang/Analysis/AnalysisContext.h" 17a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7Torne (Richard Coles)#include "clang/Analysis/CFG.h" 18f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)#include "clang/Analysis/Analyses/ReachableCode.h" 19a1401311d1ab56c4ed0a474bd38c108f75cb0cd9Torne (Richard Coles)#include "clang/Analysis/Analyses/PrintfFormatString.h" 20a3f6a49ab37290eeeb8db0f41ec0f1cb74a68be7Torne (Richard Coles)#include "clang/AST/ASTContext.h" 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/CharUnits.h" 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/DeclObjC.h" 23eb525c5499e34cc9c4b825d6d9e75bb07cc06aceBen Murdoch#include "clang/AST/ExprCXX.h" 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/ExprObjC.h" 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/DeclObjC.h" 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/StmtCXX.h" 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/AST/StmtObjC.h" 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/Lex/LiteralSupport.h" 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "clang/Lex/Preprocessor.h" 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "llvm/ADT/BitVector.h" 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "llvm/ADT/STLExtras.h" 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <limits> 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include <queue> 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)using namespace clang; 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// getLocationOfStringLiteralByte - Return a source location that points to the 37f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)/// specified byte of the specified string literal. 38f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles)/// 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// Strings are amazingly complex. They can be formed from multiple tokens and 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// can have escape sequences in them in addition to the usual trigraph and 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// escaped newline business. This routine handles this complexity. 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)SourceLocation Sema::getLocationOfStringLiteralByte(const StringLiteral *SL, 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned ByteNo) const { 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(!SL->isWide() && "This doesn't work for wide strings yet"); 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Loop over all of the tokens in this string until we find the one that 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // contains the byte we're looking for. 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned TokNo = 0; 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) while (1) { 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(TokNo < SL->getNumConcatenated() && "Invalid byte number!"); 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SourceLocation StrTokLoc = SL->getStrTokenLoc(TokNo); 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Get the spelling of the string so that we can get the data that makes up 555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // the string literal, not the identifier for the macro it is potentially 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // expanded through. 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SourceLocation StrTokSpellingLoc = SourceMgr.getSpellingLoc(StrTokLoc); 585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Re-lex the token to get its length and original spelling. 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::pair<FileID, unsigned> LocInfo = 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SourceMgr.getDecomposedLoc(StrTokSpellingLoc); 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) std::pair<const char *,const char *> Buffer = 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) SourceMgr.getBufferData(LocInfo.first); 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) const char *StrData = Buffer.first+LocInfo.second; 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Create a langops struct and enable trigraphs. This is sufficient for 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // relexing tokens. 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LangOptions LangOpts; 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) LangOpts.Trigraphs = true; 70f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) 71f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) // Create a lexer starting at the beginning of this token. 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Lexer TheLexer(StrTokSpellingLoc, LangOpts, Buffer.first, StrData, 73f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) Buffer.second); 74f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) Token TheTok; 75f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) TheLexer.LexFromRawLexer(TheTok); 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Use the StringLiteralParser to compute the length of the string in bytes. 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) StringLiteralParser SLP(&TheTok, 1, PP); 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned TokNumBytes = SLP.GetStringLength(); 805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 815821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // If the byte is in this token, return the location of the byte. 825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (ByteNo < TokNumBytes || 835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (ByteNo == TokNumBytes && TokNo == SL->getNumConcatenated())) { 845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned Offset = 855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) StringLiteralParser::getOffsetOfStringByte(TheTok, ByteNo, PP); 865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Now that we know the offset of the token in the spelling, use the 885821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // preprocessor to get the offset in the original source. 895821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return PP.AdvanceToTokenCharacter(StrTokLoc, Offset); 905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 915821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 925821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Move to the next string token. 935821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ++TokNo; 945821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) ByteNo -= TokNumBytes; 955821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 965821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 975821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// CheckablePrintfAttr - does a function call have a "printf" attribute 995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)/// and arguments that merit checking? 1005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool Sema::CheckablePrintfAttr(const FormatAttr *Format, CallExpr *TheCall) { 1015821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (Format->getType() == "printf") return true; 1025821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (Format->getType() == "printf0") { 1035821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // printf0 allows null "format" string; if so don't check format/args 1045821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) unsigned format_idx = Format->getFormatIdx() - 1; 1055821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // Does the index refer to the implicit object argument? 106a1401311d1ab56c4ed0a474bd38c108f75cb0cd9Torne (Richard Coles) if (isa<CXXMemberCallExpr>(TheCall)) { 1075821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (format_idx == 0) 1085821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1095821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) --format_idx; 1105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (format_idx < TheCall->getNumArgs()) { 1125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Expr *Format = TheCall->getArg(format_idx)->IgnoreParenCasts(); 1135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!Format->isNullPointerConstant(Context, 1145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Expr::NPC_ValueDependentIsNull)) 115a1401311d1ab56c4ed0a474bd38c108f75cb0cd9Torne (Richard Coles) return true; 1165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 1185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return false; 1195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 1205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)Action::OwningExprResult 1225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)Sema::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) { 1235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) OwningExprResult TheCallResult(Owned(TheCall)); 1245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 1255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) switch (BuiltinID) { 1265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin___CFStringMakeConstantString: 1275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) assert(TheCall->getNumArgs() == 1 && 1285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) "Wrong # arguments to builtin CFStringMakeConstantString"); 1295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (CheckObjCString(TheCall->getArg(0))) 1305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 1315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_stdarg_start: 1335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_va_start: 1345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinVAStart(TheCall)) 1355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 1365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isgreater: 1385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isgreaterequal: 1395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isless: 140f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__builtin_islessequal: 1415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_islessgreater: 1425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isunordered: 1435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinUnorderedCompare(TheCall)) 1445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 145f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) break; 146f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__builtin_fpclassify: 147f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) if (SemaBuiltinFPClassification(TheCall, 6)) 148f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) return ExprError(); 1495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isfinite: 1515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isinf: 152f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__builtin_isinf_sign: 1535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isnan: 1545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_isnormal: 1555821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinFPClassification(TheCall, 1)) 1565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 157f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) break; 1585821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_return_address: 1595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_frame_address: 1605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinStackAddress(TheCall)) 1615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 162f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) break; 1635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_eh_return_data_regno: 1645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinEHReturnDataRegNo(TheCall)) 1655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 1665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_shufflevector: 1685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return SemaBuiltinShuffleVector(TheCall); 1695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // TheCall will be freed by the smart pointer here, but that's fine, since 1705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // SemaBuiltinShuffleVector guts it, but then doesn't release it. 1715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_prefetch: 1725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinPrefetch(TheCall)) 173f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) return ExprError(); 1742a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) break; 1755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_object_size: 176f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) if (SemaBuiltinObjectSize(TheCall)) 1775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 1785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__builtin_longjmp: 1805821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinLongjmp(TheCall)) 181f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) return ExprError(); 1825821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) break; 1835821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_fetch_and_add: 1845821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_fetch_and_sub: 1855821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_fetch_and_or: 1865821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_fetch_and_and: 1875821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_fetch_and_xor: 188f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__sync_fetch_and_nand: 1892a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) case Builtin::BI__sync_add_and_fetch: 1905821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_sub_and_fetch: 1912a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) case Builtin::BI__sync_and_and_fetch: 192f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__sync_or_and_fetch: 1932a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) case Builtin::BI__sync_xor_and_fetch: 1942a99a7e74a7f215066514fe81d2bfa6639d9edddTorne (Richard Coles) case Builtin::BI__sync_nand_and_fetch: 1955f1c94371a64b3196d4be9466099bb892df9b88eTorne (Richard Coles) case Builtin::BI__sync_val_compare_and_swap: 1967dbb3d5cf0c15f500944d211057644d6a2f37371Ben Murdoch case Builtin::BI__sync_bool_compare_and_swap: 197f2477e01787aa58f445919b809d89e252beef54fTorne (Richard Coles) case Builtin::BI__sync_lock_test_and_set: 1985821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) case Builtin::BI__sync_lock_release: 1995821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (SemaBuiltinAtomicOverloaded(TheCall)) 2005821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return ExprError(); 201 break; 202 } 203 204 return move(TheCallResult); 205} 206 207/// CheckFunctionCall - Check a direct function call for various correctness 208/// and safety properties not strictly enforced by the C type system. 209bool Sema::CheckFunctionCall(FunctionDecl *FDecl, CallExpr *TheCall) { 210 // Get the IdentifierInfo* for the called function. 211 IdentifierInfo *FnInfo = FDecl->getIdentifier(); 212 213 // None of the checks below are needed for functions that don't have 214 // simple names (e.g., C++ conversion functions). 215 if (!FnInfo) 216 return false; 217 218 // FIXME: This mechanism should be abstracted to be less fragile and 219 // more efficient. For example, just map function ids to custom 220 // handlers. 221 222 // Printf checking. 223 if (const FormatAttr *Format = FDecl->getAttr<FormatAttr>()) { 224 if (CheckablePrintfAttr(Format, TheCall)) { 225 bool HasVAListArg = Format->getFirstArg() == 0; 226 if (!HasVAListArg) { 227 if (const FunctionProtoType *Proto 228 = FDecl->getType()->getAs<FunctionProtoType>()) 229 HasVAListArg = !Proto->isVariadic(); 230 } 231 CheckPrintfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1, 232 HasVAListArg ? 0 : Format->getFirstArg() - 1); 233 } 234 } 235 236 for (const NonNullAttr *NonNull = FDecl->getAttr<NonNullAttr>(); NonNull; 237 NonNull = NonNull->getNext<NonNullAttr>()) 238 CheckNonNullArguments(NonNull, TheCall); 239 240 return false; 241} 242 243bool Sema::CheckBlockCall(NamedDecl *NDecl, CallExpr *TheCall) { 244 // Printf checking. 245 const FormatAttr *Format = NDecl->getAttr<FormatAttr>(); 246 if (!Format) 247 return false; 248 249 const VarDecl *V = dyn_cast<VarDecl>(NDecl); 250 if (!V) 251 return false; 252 253 QualType Ty = V->getType(); 254 if (!Ty->isBlockPointerType()) 255 return false; 256 257 if (!CheckablePrintfAttr(Format, TheCall)) 258 return false; 259 260 bool HasVAListArg = Format->getFirstArg() == 0; 261 if (!HasVAListArg) { 262 const FunctionType *FT = 263 Ty->getAs<BlockPointerType>()->getPointeeType()->getAs<FunctionType>(); 264 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 265 HasVAListArg = !Proto->isVariadic(); 266 } 267 CheckPrintfArguments(TheCall, HasVAListArg, Format->getFormatIdx() - 1, 268 HasVAListArg ? 0 : Format->getFirstArg() - 1); 269 270 return false; 271} 272 273/// SemaBuiltinAtomicOverloaded - We have a call to a function like 274/// __sync_fetch_and_add, which is an overloaded function based on the pointer 275/// type of its first argument. The main ActOnCallExpr routines have already 276/// promoted the types of arguments because all of these calls are prototyped as 277/// void(...). 278/// 279/// This function goes through and does final semantic checking for these 280/// builtins, 281bool Sema::SemaBuiltinAtomicOverloaded(CallExpr *TheCall) { 282 DeclRefExpr *DRE =cast<DeclRefExpr>(TheCall->getCallee()->IgnoreParenCasts()); 283 FunctionDecl *FDecl = cast<FunctionDecl>(DRE->getDecl()); 284 285 // Ensure that we have at least one argument to do type inference from. 286 if (TheCall->getNumArgs() < 1) 287 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 288 << 0 << TheCall->getCallee()->getSourceRange(); 289 290 // Inspect the first argument of the atomic builtin. This should always be 291 // a pointer type, whose element is an integral scalar or pointer type. 292 // Because it is a pointer type, we don't have to worry about any implicit 293 // casts here. 294 Expr *FirstArg = TheCall->getArg(0); 295 if (!FirstArg->getType()->isPointerType()) 296 return Diag(DRE->getLocStart(), diag::err_atomic_builtin_must_be_pointer) 297 << FirstArg->getType() << FirstArg->getSourceRange(); 298 299 QualType ValType = FirstArg->getType()->getAs<PointerType>()->getPointeeType(); 300 if (!ValType->isIntegerType() && !ValType->isPointerType() && 301 !ValType->isBlockPointerType()) 302 return Diag(DRE->getLocStart(), 303 diag::err_atomic_builtin_must_be_pointer_intptr) 304 << FirstArg->getType() << FirstArg->getSourceRange(); 305 306 // We need to figure out which concrete builtin this maps onto. For example, 307 // __sync_fetch_and_add with a 2 byte object turns into 308 // __sync_fetch_and_add_2. 309#define BUILTIN_ROW(x) \ 310 { Builtin::BI##x##_1, Builtin::BI##x##_2, Builtin::BI##x##_4, \ 311 Builtin::BI##x##_8, Builtin::BI##x##_16 } 312 313 static const unsigned BuiltinIndices[][5] = { 314 BUILTIN_ROW(__sync_fetch_and_add), 315 BUILTIN_ROW(__sync_fetch_and_sub), 316 BUILTIN_ROW(__sync_fetch_and_or), 317 BUILTIN_ROW(__sync_fetch_and_and), 318 BUILTIN_ROW(__sync_fetch_and_xor), 319 BUILTIN_ROW(__sync_fetch_and_nand), 320 321 BUILTIN_ROW(__sync_add_and_fetch), 322 BUILTIN_ROW(__sync_sub_and_fetch), 323 BUILTIN_ROW(__sync_and_and_fetch), 324 BUILTIN_ROW(__sync_or_and_fetch), 325 BUILTIN_ROW(__sync_xor_and_fetch), 326 BUILTIN_ROW(__sync_nand_and_fetch), 327 328 BUILTIN_ROW(__sync_val_compare_and_swap), 329 BUILTIN_ROW(__sync_bool_compare_and_swap), 330 BUILTIN_ROW(__sync_lock_test_and_set), 331 BUILTIN_ROW(__sync_lock_release) 332 }; 333#undef BUILTIN_ROW 334 335 // Determine the index of the size. 336 unsigned SizeIndex; 337 switch (Context.getTypeSizeInChars(ValType).getQuantity()) { 338 case 1: SizeIndex = 0; break; 339 case 2: SizeIndex = 1; break; 340 case 4: SizeIndex = 2; break; 341 case 8: SizeIndex = 3; break; 342 case 16: SizeIndex = 4; break; 343 default: 344 return Diag(DRE->getLocStart(), diag::err_atomic_builtin_pointer_size) 345 << FirstArg->getType() << FirstArg->getSourceRange(); 346 } 347 348 // Each of these builtins has one pointer argument, followed by some number of 349 // values (0, 1 or 2) followed by a potentially empty varags list of stuff 350 // that we ignore. Find out which row of BuiltinIndices to read from as well 351 // as the number of fixed args. 352 unsigned BuiltinID = FDecl->getBuiltinID(); 353 unsigned BuiltinIndex, NumFixed = 1; 354 switch (BuiltinID) { 355 default: assert(0 && "Unknown overloaded atomic builtin!"); 356 case Builtin::BI__sync_fetch_and_add: BuiltinIndex = 0; break; 357 case Builtin::BI__sync_fetch_and_sub: BuiltinIndex = 1; break; 358 case Builtin::BI__sync_fetch_and_or: BuiltinIndex = 2; break; 359 case Builtin::BI__sync_fetch_and_and: BuiltinIndex = 3; break; 360 case Builtin::BI__sync_fetch_and_xor: BuiltinIndex = 4; break; 361 case Builtin::BI__sync_fetch_and_nand:BuiltinIndex = 5; break; 362 363 case Builtin::BI__sync_add_and_fetch: BuiltinIndex = 6; break; 364 case Builtin::BI__sync_sub_and_fetch: BuiltinIndex = 7; break; 365 case Builtin::BI__sync_and_and_fetch: BuiltinIndex = 8; break; 366 case Builtin::BI__sync_or_and_fetch: BuiltinIndex = 9; break; 367 case Builtin::BI__sync_xor_and_fetch: BuiltinIndex =10; break; 368 case Builtin::BI__sync_nand_and_fetch:BuiltinIndex =11; break; 369 370 case Builtin::BI__sync_val_compare_and_swap: 371 BuiltinIndex = 12; 372 NumFixed = 2; 373 break; 374 case Builtin::BI__sync_bool_compare_and_swap: 375 BuiltinIndex = 13; 376 NumFixed = 2; 377 break; 378 case Builtin::BI__sync_lock_test_and_set: BuiltinIndex = 14; break; 379 case Builtin::BI__sync_lock_release: 380 BuiltinIndex = 15; 381 NumFixed = 0; 382 break; 383 } 384 385 // Now that we know how many fixed arguments we expect, first check that we 386 // have at least that many. 387 if (TheCall->getNumArgs() < 1+NumFixed) 388 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 389 << 0 << TheCall->getCallee()->getSourceRange(); 390 391 392 // Get the decl for the concrete builtin from this, we can tell what the 393 // concrete integer type we should convert to is. 394 unsigned NewBuiltinID = BuiltinIndices[BuiltinIndex][SizeIndex]; 395 const char *NewBuiltinName = Context.BuiltinInfo.GetName(NewBuiltinID); 396 IdentifierInfo *NewBuiltinII = PP.getIdentifierInfo(NewBuiltinName); 397 FunctionDecl *NewBuiltinDecl = 398 cast<FunctionDecl>(LazilyCreateBuiltin(NewBuiltinII, NewBuiltinID, 399 TUScope, false, DRE->getLocStart())); 400 const FunctionProtoType *BuiltinFT = 401 NewBuiltinDecl->getType()->getAs<FunctionProtoType>(); 402 ValType = BuiltinFT->getArgType(0)->getAs<PointerType>()->getPointeeType(); 403 404 // If the first type needs to be converted (e.g. void** -> int*), do it now. 405 if (BuiltinFT->getArgType(0) != FirstArg->getType()) { 406 ImpCastExprToType(FirstArg, BuiltinFT->getArgType(0), CastExpr::CK_BitCast); 407 TheCall->setArg(0, FirstArg); 408 } 409 410 // Next, walk the valid ones promoting to the right type. 411 for (unsigned i = 0; i != NumFixed; ++i) { 412 Expr *Arg = TheCall->getArg(i+1); 413 414 // If the argument is an implicit cast, then there was a promotion due to 415 // "...", just remove it now. 416 if (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Arg)) { 417 Arg = ICE->getSubExpr(); 418 ICE->setSubExpr(0); 419 ICE->Destroy(Context); 420 TheCall->setArg(i+1, Arg); 421 } 422 423 // GCC does an implicit conversion to the pointer or integer ValType. This 424 // can fail in some cases (1i -> int**), check for this error case now. 425 CastExpr::CastKind Kind = CastExpr::CK_Unknown; 426 CXXMethodDecl *ConversionDecl = 0; 427 if (CheckCastTypes(Arg->getSourceRange(), ValType, Arg, Kind, 428 ConversionDecl)) 429 return true; 430 431 // Okay, we have something that *can* be converted to the right type. Check 432 // to see if there is a potentially weird extension going on here. This can 433 // happen when you do an atomic operation on something like an char* and 434 // pass in 42. The 42 gets converted to char. This is even more strange 435 // for things like 45.123 -> char, etc. 436 // FIXME: Do this check. 437 ImpCastExprToType(Arg, ValType, Kind, /*isLvalue=*/false); 438 TheCall->setArg(i+1, Arg); 439 } 440 441 // Switch the DeclRefExpr to refer to the new decl. 442 DRE->setDecl(NewBuiltinDecl); 443 DRE->setType(NewBuiltinDecl->getType()); 444 445 // Set the callee in the CallExpr. 446 // FIXME: This leaks the original parens and implicit casts. 447 Expr *PromotedCall = DRE; 448 UsualUnaryConversions(PromotedCall); 449 TheCall->setCallee(PromotedCall); 450 451 452 // Change the result type of the call to match the result type of the decl. 453 TheCall->setType(NewBuiltinDecl->getResultType()); 454 return false; 455} 456 457 458/// CheckObjCString - Checks that the argument to the builtin 459/// CFString constructor is correct 460/// FIXME: GCC currently emits the following warning: 461/// "warning: input conversion stopped due to an input byte that does not 462/// belong to the input codeset UTF-8" 463/// Note: It might also make sense to do the UTF-16 conversion here (would 464/// simplify the backend). 465bool Sema::CheckObjCString(Expr *Arg) { 466 Arg = Arg->IgnoreParenCasts(); 467 StringLiteral *Literal = dyn_cast<StringLiteral>(Arg); 468 469 if (!Literal || Literal->isWide()) { 470 Diag(Arg->getLocStart(), diag::err_cfstring_literal_not_string_constant) 471 << Arg->getSourceRange(); 472 return true; 473 } 474 475 const char *Data = Literal->getStrData(); 476 unsigned Length = Literal->getByteLength(); 477 478 for (unsigned i = 0; i < Length; ++i) { 479 if (!Data[i]) { 480 Diag(getLocationOfStringLiteralByte(Literal, i), 481 diag::warn_cfstring_literal_contains_nul_character) 482 << Arg->getSourceRange(); 483 break; 484 } 485 } 486 487 return false; 488} 489 490/// SemaBuiltinVAStart - Check the arguments to __builtin_va_start for validity. 491/// Emit an error and return true on failure, return false on success. 492bool Sema::SemaBuiltinVAStart(CallExpr *TheCall) { 493 Expr *Fn = TheCall->getCallee(); 494 if (TheCall->getNumArgs() > 2) { 495 Diag(TheCall->getArg(2)->getLocStart(), 496 diag::err_typecheck_call_too_many_args) 497 << 0 /*function call*/ << Fn->getSourceRange() 498 << SourceRange(TheCall->getArg(2)->getLocStart(), 499 (*(TheCall->arg_end()-1))->getLocEnd()); 500 return true; 501 } 502 503 if (TheCall->getNumArgs() < 2) { 504 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 505 << 0 /*function call*/; 506 } 507 508 // Determine whether the current function is variadic or not. 509 BlockScopeInfo *CurBlock = getCurBlock(); 510 bool isVariadic; 511 if (CurBlock) 512 isVariadic = CurBlock->isVariadic; 513 else if (getCurFunctionDecl()) { 514 if (FunctionProtoType* FTP = 515 dyn_cast<FunctionProtoType>(getCurFunctionDecl()->getType())) 516 isVariadic = FTP->isVariadic(); 517 else 518 isVariadic = false; 519 } else { 520 isVariadic = getCurMethodDecl()->isVariadic(); 521 } 522 523 if (!isVariadic) { 524 Diag(Fn->getLocStart(), diag::err_va_start_used_in_non_variadic_function); 525 return true; 526 } 527 528 // Verify that the second argument to the builtin is the last argument of the 529 // current function or method. 530 bool SecondArgIsLastNamedArgument = false; 531 const Expr *Arg = TheCall->getArg(1)->IgnoreParenCasts(); 532 533 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(Arg)) { 534 if (const ParmVarDecl *PV = dyn_cast<ParmVarDecl>(DR->getDecl())) { 535 // FIXME: This isn't correct for methods (results in bogus warning). 536 // Get the last formal in the current function. 537 const ParmVarDecl *LastArg; 538 if (CurBlock) 539 LastArg = *(CurBlock->TheDecl->param_end()-1); 540 else if (FunctionDecl *FD = getCurFunctionDecl()) 541 LastArg = *(FD->param_end()-1); 542 else 543 LastArg = *(getCurMethodDecl()->param_end()-1); 544 SecondArgIsLastNamedArgument = PV == LastArg; 545 } 546 } 547 548 if (!SecondArgIsLastNamedArgument) 549 Diag(TheCall->getArg(1)->getLocStart(), 550 diag::warn_second_parameter_of_va_start_not_last_named_argument); 551 return false; 552} 553 554/// SemaBuiltinUnorderedCompare - Handle functions like __builtin_isgreater and 555/// friends. This is declared to take (...), so we have to check everything. 556bool Sema::SemaBuiltinUnorderedCompare(CallExpr *TheCall) { 557 if (TheCall->getNumArgs() < 2) 558 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 559 << 0 /*function call*/; 560 if (TheCall->getNumArgs() > 2) 561 return Diag(TheCall->getArg(2)->getLocStart(), 562 diag::err_typecheck_call_too_many_args) 563 << 0 /*function call*/ 564 << SourceRange(TheCall->getArg(2)->getLocStart(), 565 (*(TheCall->arg_end()-1))->getLocEnd()); 566 567 Expr *OrigArg0 = TheCall->getArg(0); 568 Expr *OrigArg1 = TheCall->getArg(1); 569 570 // Do standard promotions between the two arguments, returning their common 571 // type. 572 QualType Res = UsualArithmeticConversions(OrigArg0, OrigArg1, false); 573 574 // Make sure any conversions are pushed back into the call; this is 575 // type safe since unordered compare builtins are declared as "_Bool 576 // foo(...)". 577 TheCall->setArg(0, OrigArg0); 578 TheCall->setArg(1, OrigArg1); 579 580 if (OrigArg0->isTypeDependent() || OrigArg1->isTypeDependent()) 581 return false; 582 583 // If the common type isn't a real floating type, then the arguments were 584 // invalid for this operation. 585 if (!Res->isRealFloatingType()) 586 return Diag(OrigArg0->getLocStart(), 587 diag::err_typecheck_call_invalid_ordered_compare) 588 << OrigArg0->getType() << OrigArg1->getType() 589 << SourceRange(OrigArg0->getLocStart(), OrigArg1->getLocEnd()); 590 591 return false; 592} 593 594/// SemaBuiltinSemaBuiltinFPClassification - Handle functions like 595/// __builtin_isnan and friends. This is declared to take (...), so we have 596/// to check everything. We expect the last argument to be a floating point 597/// value. 598bool Sema::SemaBuiltinFPClassification(CallExpr *TheCall, unsigned NumArgs) { 599 if (TheCall->getNumArgs() < NumArgs) 600 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_few_args) 601 << 0 /*function call*/; 602 if (TheCall->getNumArgs() > NumArgs) 603 return Diag(TheCall->getArg(NumArgs)->getLocStart(), 604 diag::err_typecheck_call_too_many_args) 605 << 0 /*function call*/ 606 << SourceRange(TheCall->getArg(NumArgs)->getLocStart(), 607 (*(TheCall->arg_end()-1))->getLocEnd()); 608 609 Expr *OrigArg = TheCall->getArg(NumArgs-1); 610 611 if (OrigArg->isTypeDependent()) 612 return false; 613 614 // This operation requires a floating-point number 615 if (!OrigArg->getType()->isRealFloatingType()) 616 return Diag(OrigArg->getLocStart(), 617 diag::err_typecheck_call_invalid_unary_fp) 618 << OrigArg->getType() << OrigArg->getSourceRange(); 619 620 return false; 621} 622 623bool Sema::SemaBuiltinStackAddress(CallExpr *TheCall) { 624 // The signature for these builtins is exact; the only thing we need 625 // to check is that the argument is a constant. 626 SourceLocation Loc; 627 if (!TheCall->getArg(0)->isTypeDependent() && 628 !TheCall->getArg(0)->isValueDependent() && 629 !TheCall->getArg(0)->isIntegerConstantExpr(Context, &Loc)) 630 return Diag(Loc, diag::err_stack_const_level) << TheCall->getSourceRange(); 631 632 return false; 633} 634 635/// SemaBuiltinShuffleVector - Handle __builtin_shufflevector. 636// This is declared to take (...), so we have to check everything. 637Action::OwningExprResult Sema::SemaBuiltinShuffleVector(CallExpr *TheCall) { 638 if (TheCall->getNumArgs() < 3) 639 return ExprError(Diag(TheCall->getLocEnd(), 640 diag::err_typecheck_call_too_few_args) 641 << 0 /*function call*/ << TheCall->getSourceRange()); 642 643 unsigned numElements = std::numeric_limits<unsigned>::max(); 644 if (!TheCall->getArg(0)->isTypeDependent() && 645 !TheCall->getArg(1)->isTypeDependent()) { 646 QualType FAType = TheCall->getArg(0)->getType(); 647 QualType SAType = TheCall->getArg(1)->getType(); 648 649 if (!FAType->isVectorType() || !SAType->isVectorType()) { 650 Diag(TheCall->getLocStart(), diag::err_shufflevector_non_vector) 651 << SourceRange(TheCall->getArg(0)->getLocStart(), 652 TheCall->getArg(1)->getLocEnd()); 653 return ExprError(); 654 } 655 656 if (!Context.hasSameUnqualifiedType(FAType, SAType)) { 657 Diag(TheCall->getLocStart(), diag::err_shufflevector_incompatible_vector) 658 << SourceRange(TheCall->getArg(0)->getLocStart(), 659 TheCall->getArg(1)->getLocEnd()); 660 return ExprError(); 661 } 662 663 numElements = FAType->getAs<VectorType>()->getNumElements(); 664 if (TheCall->getNumArgs() != numElements+2) { 665 if (TheCall->getNumArgs() < numElements+2) 666 return ExprError(Diag(TheCall->getLocEnd(), 667 diag::err_typecheck_call_too_few_args) 668 << 0 /*function call*/ << TheCall->getSourceRange()); 669 return ExprError(Diag(TheCall->getLocEnd(), 670 diag::err_typecheck_call_too_many_args) 671 << 0 /*function call*/ << TheCall->getSourceRange()); 672 } 673 } 674 675 for (unsigned i = 2; i < TheCall->getNumArgs(); i++) { 676 if (TheCall->getArg(i)->isTypeDependent() || 677 TheCall->getArg(i)->isValueDependent()) 678 continue; 679 680 llvm::APSInt Result(32); 681 if (!TheCall->getArg(i)->isIntegerConstantExpr(Result, Context)) 682 return ExprError(Diag(TheCall->getLocStart(), 683 diag::err_shufflevector_nonconstant_argument) 684 << TheCall->getArg(i)->getSourceRange()); 685 686 if (Result.getActiveBits() > 64 || Result.getZExtValue() >= numElements*2) 687 return ExprError(Diag(TheCall->getLocStart(), 688 diag::err_shufflevector_argument_too_large) 689 << TheCall->getArg(i)->getSourceRange()); 690 } 691 692 llvm::SmallVector<Expr*, 32> exprs; 693 694 for (unsigned i = 0, e = TheCall->getNumArgs(); i != e; i++) { 695 exprs.push_back(TheCall->getArg(i)); 696 TheCall->setArg(i, 0); 697 } 698 699 return Owned(new (Context) ShuffleVectorExpr(Context, exprs.begin(), 700 exprs.size(), exprs[0]->getType(), 701 TheCall->getCallee()->getLocStart(), 702 TheCall->getRParenLoc())); 703} 704 705/// SemaBuiltinPrefetch - Handle __builtin_prefetch. 706// This is declared to take (const void*, ...) and can take two 707// optional constant int args. 708bool Sema::SemaBuiltinPrefetch(CallExpr *TheCall) { 709 unsigned NumArgs = TheCall->getNumArgs(); 710 711 if (NumArgs > 3) 712 return Diag(TheCall->getLocEnd(), diag::err_typecheck_call_too_many_args) 713 << 0 /*function call*/ << TheCall->getSourceRange(); 714 715 // Argument 0 is checked for us and the remaining arguments must be 716 // constant integers. 717 for (unsigned i = 1; i != NumArgs; ++i) { 718 Expr *Arg = TheCall->getArg(i); 719 if (Arg->isTypeDependent()) 720 continue; 721 722 if (!Arg->getType()->isIntegralType()) 723 return Diag(TheCall->getLocStart(), diag::err_prefetch_invalid_arg_type) 724 << Arg->getSourceRange(); 725 726 ImpCastExprToType(Arg, Context.IntTy, CastExpr::CK_IntegralCast); 727 TheCall->setArg(i, Arg); 728 729 if (Arg->isValueDependent()) 730 continue; 731 732 llvm::APSInt Result; 733 if (!Arg->isIntegerConstantExpr(Result, Context)) 734 return Diag(TheCall->getLocStart(), diag::err_prefetch_invalid_arg_ice) 735 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 736 737 // FIXME: gcc issues a warning and rewrites these to 0. These 738 // seems especially odd for the third argument since the default 739 // is 3. 740 if (i == 1) { 741 if (Result.getLimitedValue() > 1) 742 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 743 << "0" << "1" << Arg->getSourceRange(); 744 } else { 745 if (Result.getLimitedValue() > 3) 746 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 747 << "0" << "3" << Arg->getSourceRange(); 748 } 749 } 750 751 return false; 752} 753 754/// SemaBuiltinEHReturnDataRegNo - Handle __builtin_eh_return_data_regno, the 755/// operand must be an integer constant. 756bool Sema::SemaBuiltinEHReturnDataRegNo(CallExpr *TheCall) { 757 llvm::APSInt Result; 758 if (!TheCall->getArg(0)->isIntegerConstantExpr(Result, Context)) 759 return Diag(TheCall->getLocStart(), diag::err_expr_not_ice) 760 << TheCall->getArg(0)->getSourceRange(); 761 762 return false; 763} 764 765 766/// SemaBuiltinObjectSize - Handle __builtin_object_size(void *ptr, 767/// int type). This simply type checks that type is one of the defined 768/// constants (0-3). 769// For compatability check 0-3, llvm only handles 0 and 2. 770bool Sema::SemaBuiltinObjectSize(CallExpr *TheCall) { 771 Expr *Arg = TheCall->getArg(1); 772 if (Arg->isTypeDependent()) 773 return false; 774 775 QualType ArgType = Arg->getType(); 776 const BuiltinType *BT = ArgType->getAs<BuiltinType>(); 777 llvm::APSInt Result(32); 778 if (!BT || BT->getKind() != BuiltinType::Int) 779 return Diag(TheCall->getLocStart(), diag::err_object_size_invalid_argument) 780 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 781 782 if (Arg->isValueDependent()) 783 return false; 784 785 if (!Arg->isIntegerConstantExpr(Result, Context)) { 786 return Diag(TheCall->getLocStart(), diag::err_object_size_invalid_argument) 787 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 788 } 789 790 if (Result.getSExtValue() < 0 || Result.getSExtValue() > 3) { 791 return Diag(TheCall->getLocStart(), diag::err_argument_invalid_range) 792 << "0" << "3" << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 793 } 794 795 return false; 796} 797 798/// SemaBuiltinLongjmp - Handle __builtin_longjmp(void *env[5], int val). 799/// This checks that val is a constant 1. 800bool Sema::SemaBuiltinLongjmp(CallExpr *TheCall) { 801 Expr *Arg = TheCall->getArg(1); 802 if (Arg->isTypeDependent() || Arg->isValueDependent()) 803 return false; 804 805 llvm::APSInt Result(32); 806 if (!Arg->isIntegerConstantExpr(Result, Context) || Result != 1) 807 return Diag(TheCall->getLocStart(), diag::err_builtin_longjmp_invalid_val) 808 << SourceRange(Arg->getLocStart(), Arg->getLocEnd()); 809 810 return false; 811} 812 813// Handle i > 1 ? "x" : "y", recursivelly 814bool Sema::SemaCheckStringLiteral(const Expr *E, const CallExpr *TheCall, 815 bool HasVAListArg, 816 unsigned format_idx, unsigned firstDataArg) { 817 if (E->isTypeDependent() || E->isValueDependent()) 818 return false; 819 820 switch (E->getStmtClass()) { 821 case Stmt::ConditionalOperatorClass: { 822 const ConditionalOperator *C = cast<ConditionalOperator>(E); 823 return SemaCheckStringLiteral(C->getTrueExpr(), TheCall, 824 HasVAListArg, format_idx, firstDataArg) 825 && SemaCheckStringLiteral(C->getRHS(), TheCall, 826 HasVAListArg, format_idx, firstDataArg); 827 } 828 829 case Stmt::ImplicitCastExprClass: { 830 const ImplicitCastExpr *Expr = cast<ImplicitCastExpr>(E); 831 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 832 format_idx, firstDataArg); 833 } 834 835 case Stmt::ParenExprClass: { 836 const ParenExpr *Expr = cast<ParenExpr>(E); 837 return SemaCheckStringLiteral(Expr->getSubExpr(), TheCall, HasVAListArg, 838 format_idx, firstDataArg); 839 } 840 841 case Stmt::DeclRefExprClass: { 842 const DeclRefExpr *DR = cast<DeclRefExpr>(E); 843 844 // As an exception, do not flag errors for variables binding to 845 // const string literals. 846 if (const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl())) { 847 bool isConstant = false; 848 QualType T = DR->getType(); 849 850 if (const ArrayType *AT = Context.getAsArrayType(T)) { 851 isConstant = AT->getElementType().isConstant(Context); 852 } else if (const PointerType *PT = T->getAs<PointerType>()) { 853 isConstant = T.isConstant(Context) && 854 PT->getPointeeType().isConstant(Context); 855 } 856 857 if (isConstant) { 858 if (const Expr *Init = VD->getAnyInitializer()) 859 return SemaCheckStringLiteral(Init, TheCall, 860 HasVAListArg, format_idx, firstDataArg); 861 } 862 863 // For vprintf* functions (i.e., HasVAListArg==true), we add a 864 // special check to see if the format string is a function parameter 865 // of the function calling the printf function. If the function 866 // has an attribute indicating it is a printf-like function, then we 867 // should suppress warnings concerning non-literals being used in a call 868 // to a vprintf function. For example: 869 // 870 // void 871 // logmessage(char const *fmt __attribute__ (format (printf, 1, 2)), ...){ 872 // va_list ap; 873 // va_start(ap, fmt); 874 // vprintf(fmt, ap); // Do NOT emit a warning about "fmt". 875 // ... 876 // 877 // 878 // FIXME: We don't have full attribute support yet, so just check to see 879 // if the argument is a DeclRefExpr that references a parameter. We'll 880 // add proper support for checking the attribute later. 881 if (HasVAListArg) 882 if (isa<ParmVarDecl>(VD)) 883 return true; 884 } 885 886 return false; 887 } 888 889 case Stmt::CallExprClass: { 890 const CallExpr *CE = cast<CallExpr>(E); 891 if (const ImplicitCastExpr *ICE 892 = dyn_cast<ImplicitCastExpr>(CE->getCallee())) { 893 if (const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ICE->getSubExpr())) { 894 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(DRE->getDecl())) { 895 if (const FormatArgAttr *FA = FD->getAttr<FormatArgAttr>()) { 896 unsigned ArgIndex = FA->getFormatIdx(); 897 const Expr *Arg = CE->getArg(ArgIndex - 1); 898 899 return SemaCheckStringLiteral(Arg, TheCall, HasVAListArg, 900 format_idx, firstDataArg); 901 } 902 } 903 } 904 } 905 906 return false; 907 } 908 case Stmt::ObjCStringLiteralClass: 909 case Stmt::StringLiteralClass: { 910 const StringLiteral *StrE = NULL; 911 912 if (const ObjCStringLiteral *ObjCFExpr = dyn_cast<ObjCStringLiteral>(E)) 913 StrE = ObjCFExpr->getString(); 914 else 915 StrE = cast<StringLiteral>(E); 916 917 if (StrE) { 918 CheckPrintfString(StrE, E, TheCall, HasVAListArg, format_idx, 919 firstDataArg); 920 return true; 921 } 922 923 return false; 924 } 925 926 default: 927 return false; 928 } 929} 930 931void 932Sema::CheckNonNullArguments(const NonNullAttr *NonNull, 933 const CallExpr *TheCall) { 934 for (NonNullAttr::iterator i = NonNull->begin(), e = NonNull->end(); 935 i != e; ++i) { 936 const Expr *ArgExpr = TheCall->getArg(*i); 937 if (ArgExpr->isNullPointerConstant(Context, 938 Expr::NPC_ValueDependentIsNotNull)) 939 Diag(TheCall->getCallee()->getLocStart(), diag::warn_null_arg) 940 << ArgExpr->getSourceRange(); 941 } 942} 943 944/// CheckPrintfArguments - Check calls to printf (and similar functions) for 945/// correct use of format strings. 946/// 947/// HasVAListArg - A predicate indicating whether the printf-like 948/// function is passed an explicit va_arg argument (e.g., vprintf) 949/// 950/// format_idx - The index into Args for the format string. 951/// 952/// Improper format strings to functions in the printf family can be 953/// the source of bizarre bugs and very serious security holes. A 954/// good source of information is available in the following paper 955/// (which includes additional references): 956/// 957/// FormatGuard: Automatic Protection From printf Format String 958/// Vulnerabilities, Proceedings of the 10th USENIX Security Symposium, 2001. 959/// 960/// TODO: 961/// Functionality implemented: 962/// 963/// We can statically check the following properties for string 964/// literal format strings for non v.*printf functions (where the 965/// arguments are passed directly): 966// 967/// (1) Are the number of format conversions equal to the number of 968/// data arguments? 969/// 970/// (2) Does each format conversion correctly match the type of the 971/// corresponding data argument? 972/// 973/// Moreover, for all printf functions we can: 974/// 975/// (3) Check for a missing format string (when not caught by type checking). 976/// 977/// (4) Check for no-operation flags; e.g. using "#" with format 978/// conversion 'c' (TODO) 979/// 980/// (5) Check the use of '%n', a major source of security holes. 981/// 982/// (6) Check for malformed format conversions that don't specify anything. 983/// 984/// (7) Check for empty format strings. e.g: printf(""); 985/// 986/// (8) Check that the format string is a wide literal. 987/// 988/// All of these checks can be done by parsing the format string. 989/// 990void 991Sema::CheckPrintfArguments(const CallExpr *TheCall, bool HasVAListArg, 992 unsigned format_idx, unsigned firstDataArg) { 993 const Expr *Fn = TheCall->getCallee(); 994 995 // The way the format attribute works in GCC, the implicit this argument 996 // of member functions is counted. However, it doesn't appear in our own 997 // lists, so decrement format_idx in that case. 998 if (isa<CXXMemberCallExpr>(TheCall)) { 999 // Catch a format attribute mistakenly referring to the object argument. 1000 if (format_idx == 0) 1001 return; 1002 --format_idx; 1003 if(firstDataArg != 0) 1004 --firstDataArg; 1005 } 1006 1007 // CHECK: printf-like function is called with no format string. 1008 if (format_idx >= TheCall->getNumArgs()) { 1009 Diag(TheCall->getRParenLoc(), diag::warn_printf_missing_format_string) 1010 << Fn->getSourceRange(); 1011 return; 1012 } 1013 1014 const Expr *OrigFormatExpr = TheCall->getArg(format_idx)->IgnoreParenCasts(); 1015 1016 // CHECK: format string is not a string literal. 1017 // 1018 // Dynamically generated format strings are difficult to 1019 // automatically vet at compile time. Requiring that format strings 1020 // are string literals: (1) permits the checking of format strings by 1021 // the compiler and thereby (2) can practically remove the source of 1022 // many format string exploits. 1023 1024 // Format string can be either ObjC string (e.g. @"%d") or 1025 // C string (e.g. "%d") 1026 // ObjC string uses the same format specifiers as C string, so we can use 1027 // the same format string checking logic for both ObjC and C strings. 1028 if (SemaCheckStringLiteral(OrigFormatExpr, TheCall, HasVAListArg, format_idx, 1029 firstDataArg)) 1030 return; // Literal format string found, check done! 1031 1032 // If there are no arguments specified, warn with -Wformat-security, otherwise 1033 // warn only with -Wformat-nonliteral. 1034 if (TheCall->getNumArgs() == format_idx+1) 1035 Diag(TheCall->getArg(format_idx)->getLocStart(), 1036 diag::warn_printf_nonliteral_noargs) 1037 << OrigFormatExpr->getSourceRange(); 1038 else 1039 Diag(TheCall->getArg(format_idx)->getLocStart(), 1040 diag::warn_printf_nonliteral) 1041 << OrigFormatExpr->getSourceRange(); 1042} 1043 1044namespace { 1045class CheckPrintfHandler : public analyze_printf::FormatStringHandler { 1046 Sema &S; 1047 const StringLiteral *FExpr; 1048 const Expr *OrigFormatExpr; 1049 const unsigned NumDataArgs; 1050 const bool IsObjCLiteral; 1051 const char *Beg; // Start of format string. 1052 const bool HasVAListArg; 1053 const CallExpr *TheCall; 1054 unsigned FormatIdx; 1055 llvm::BitVector CoveredArgs; 1056 bool usesPositionalArgs; 1057 bool atFirstArg; 1058public: 1059 CheckPrintfHandler(Sema &s, const StringLiteral *fexpr, 1060 const Expr *origFormatExpr, 1061 unsigned numDataArgs, bool isObjCLiteral, 1062 const char *beg, bool hasVAListArg, 1063 const CallExpr *theCall, unsigned formatIdx) 1064 : S(s), FExpr(fexpr), OrigFormatExpr(origFormatExpr), 1065 NumDataArgs(numDataArgs), 1066 IsObjCLiteral(isObjCLiteral), Beg(beg), 1067 HasVAListArg(hasVAListArg), 1068 TheCall(theCall), FormatIdx(formatIdx), 1069 usesPositionalArgs(false), atFirstArg(true) { 1070 CoveredArgs.resize(numDataArgs); 1071 CoveredArgs.reset(); 1072 } 1073 1074 void DoneProcessing(); 1075 1076 void HandleIncompleteFormatSpecifier(const char *startSpecifier, 1077 unsigned specifierLen); 1078 1079 bool 1080 HandleInvalidConversionSpecifier(const analyze_printf::FormatSpecifier &FS, 1081 const char *startSpecifier, 1082 unsigned specifierLen); 1083 1084 virtual void HandleInvalidPosition(const char *startSpecifier, 1085 unsigned specifierLen, 1086 analyze_printf::PositionContext p); 1087 1088 virtual void HandleZeroPosition(const char *startPos, unsigned posLen); 1089 1090 void HandleNullChar(const char *nullCharacter); 1091 1092 bool HandleFormatSpecifier(const analyze_printf::FormatSpecifier &FS, 1093 const char *startSpecifier, 1094 unsigned specifierLen); 1095private: 1096 SourceRange getFormatStringRange(); 1097 SourceRange getFormatSpecifierRange(const char *startSpecifier, 1098 unsigned specifierLen); 1099 SourceLocation getLocationOfByte(const char *x); 1100 1101 bool HandleAmount(const analyze_printf::OptionalAmount &Amt, unsigned k, 1102 const char *startSpecifier, unsigned specifierLen); 1103 void HandleFlags(const analyze_printf::FormatSpecifier &FS, 1104 llvm::StringRef flag, llvm::StringRef cspec, 1105 const char *startSpecifier, unsigned specifierLen); 1106 1107 const Expr *getDataArg(unsigned i) const; 1108}; 1109} 1110 1111SourceRange CheckPrintfHandler::getFormatStringRange() { 1112 return OrigFormatExpr->getSourceRange(); 1113} 1114 1115SourceRange CheckPrintfHandler:: 1116getFormatSpecifierRange(const char *startSpecifier, unsigned specifierLen) { 1117 return SourceRange(getLocationOfByte(startSpecifier), 1118 getLocationOfByte(startSpecifier+specifierLen-1)); 1119} 1120 1121SourceLocation CheckPrintfHandler::getLocationOfByte(const char *x) { 1122 return S.getLocationOfStringLiteralByte(FExpr, x - Beg); 1123} 1124 1125void CheckPrintfHandler:: 1126HandleIncompleteFormatSpecifier(const char *startSpecifier, 1127 unsigned specifierLen) { 1128 SourceLocation Loc = getLocationOfByte(startSpecifier); 1129 S.Diag(Loc, diag::warn_printf_incomplete_specifier) 1130 << getFormatSpecifierRange(startSpecifier, specifierLen); 1131} 1132 1133void 1134CheckPrintfHandler::HandleInvalidPosition(const char *startPos, unsigned posLen, 1135 analyze_printf::PositionContext p) { 1136 SourceLocation Loc = getLocationOfByte(startPos); 1137 S.Diag(Loc, diag::warn_printf_invalid_positional_specifier) 1138 << (unsigned) p << getFormatSpecifierRange(startPos, posLen); 1139} 1140 1141void CheckPrintfHandler::HandleZeroPosition(const char *startPos, 1142 unsigned posLen) { 1143 SourceLocation Loc = getLocationOfByte(startPos); 1144 S.Diag(Loc, diag::warn_printf_zero_positional_specifier) 1145 << getFormatSpecifierRange(startPos, posLen); 1146} 1147 1148bool CheckPrintfHandler:: 1149HandleInvalidConversionSpecifier(const analyze_printf::FormatSpecifier &FS, 1150 const char *startSpecifier, 1151 unsigned specifierLen) { 1152 1153 unsigned argIndex = FS.getArgIndex(); 1154 bool keepGoing = true; 1155 if (argIndex < NumDataArgs) { 1156 // Consider the argument coverered, even though the specifier doesn't 1157 // make sense. 1158 CoveredArgs.set(argIndex); 1159 } 1160 else { 1161 // If argIndex exceeds the number of data arguments we 1162 // don't issue a warning because that is just a cascade of warnings (and 1163 // they may have intended '%%' anyway). We don't want to continue processing 1164 // the format string after this point, however, as we will like just get 1165 // gibberish when trying to match arguments. 1166 keepGoing = false; 1167 } 1168 1169 const analyze_printf::ConversionSpecifier &CS = 1170 FS.getConversionSpecifier(); 1171 SourceLocation Loc = getLocationOfByte(CS.getStart()); 1172 S.Diag(Loc, diag::warn_printf_invalid_conversion) 1173 << llvm::StringRef(CS.getStart(), CS.getLength()) 1174 << getFormatSpecifierRange(startSpecifier, specifierLen); 1175 1176 return keepGoing; 1177} 1178 1179void CheckPrintfHandler::HandleNullChar(const char *nullCharacter) { 1180 // The presence of a null character is likely an error. 1181 S.Diag(getLocationOfByte(nullCharacter), 1182 diag::warn_printf_format_string_contains_null_char) 1183 << getFormatStringRange(); 1184} 1185 1186const Expr *CheckPrintfHandler::getDataArg(unsigned i) const { 1187 return TheCall->getArg(FormatIdx + i + 1); 1188} 1189 1190 1191 1192void CheckPrintfHandler::HandleFlags(const analyze_printf::FormatSpecifier &FS, 1193 llvm::StringRef flag, 1194 llvm::StringRef cspec, 1195 const char *startSpecifier, 1196 unsigned specifierLen) { 1197 const analyze_printf::ConversionSpecifier &CS = FS.getConversionSpecifier(); 1198 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_nonsensical_flag) 1199 << flag << cspec << getFormatSpecifierRange(startSpecifier, specifierLen); 1200} 1201 1202bool 1203CheckPrintfHandler::HandleAmount(const analyze_printf::OptionalAmount &Amt, 1204 unsigned k, const char *startSpecifier, 1205 unsigned specifierLen) { 1206 1207 if (Amt.hasDataArgument()) { 1208 if (!HasVAListArg) { 1209 unsigned argIndex = Amt.getArgIndex(); 1210 if (argIndex >= NumDataArgs) { 1211 S.Diag(getLocationOfByte(Amt.getStart()), 1212 diag::warn_printf_asterisk_missing_arg) 1213 << k << getFormatSpecifierRange(startSpecifier, specifierLen); 1214 // Don't do any more checking. We will just emit 1215 // spurious errors. 1216 return false; 1217 } 1218 1219 // Type check the data argument. It should be an 'int'. 1220 // Although not in conformance with C99, we also allow the argument to be 1221 // an 'unsigned int' as that is a reasonably safe case. GCC also 1222 // doesn't emit a warning for that case. 1223 CoveredArgs.set(argIndex); 1224 const Expr *Arg = getDataArg(argIndex); 1225 QualType T = Arg->getType(); 1226 1227 const analyze_printf::ArgTypeResult &ATR = Amt.getArgType(S.Context); 1228 assert(ATR.isValid()); 1229 1230 if (!ATR.matchesType(S.Context, T)) { 1231 S.Diag(getLocationOfByte(Amt.getStart()), 1232 diag::warn_printf_asterisk_wrong_type) 1233 << k 1234 << ATR.getRepresentativeType(S.Context) << T 1235 << getFormatSpecifierRange(startSpecifier, specifierLen) 1236 << Arg->getSourceRange(); 1237 // Don't do any more checking. We will just emit 1238 // spurious errors. 1239 return false; 1240 } 1241 } 1242 } 1243 return true; 1244} 1245 1246bool 1247CheckPrintfHandler::HandleFormatSpecifier(const analyze_printf::FormatSpecifier 1248 &FS, 1249 const char *startSpecifier, 1250 unsigned specifierLen) { 1251 1252 using namespace analyze_printf; 1253 const ConversionSpecifier &CS = FS.getConversionSpecifier(); 1254 1255 if (atFirstArg) { 1256 atFirstArg = false; 1257 usesPositionalArgs = FS.usesPositionalArg(); 1258 } 1259 else if (usesPositionalArgs != FS.usesPositionalArg()) { 1260 // Cannot mix-and-match positional and non-positional arguments. 1261 S.Diag(getLocationOfByte(CS.getStart()), 1262 diag::warn_printf_mix_positional_nonpositional_args) 1263 << getFormatSpecifierRange(startSpecifier, specifierLen); 1264 return false; 1265 } 1266 1267 // First check if the field width, precision, and conversion specifier 1268 // have matching data arguments. 1269 if (!HandleAmount(FS.getFieldWidth(), /* field width */ 0, 1270 startSpecifier, specifierLen)) { 1271 return false; 1272 } 1273 1274 if (!HandleAmount(FS.getPrecision(), /* precision */ 1, 1275 startSpecifier, specifierLen)) { 1276 return false; 1277 } 1278 1279 if (!CS.consumesDataArgument()) { 1280 // FIXME: Technically specifying a precision or field width here 1281 // makes no sense. Worth issuing a warning at some point. 1282 return true; 1283 } 1284 1285 // Consume the argument. 1286 unsigned argIndex = FS.getArgIndex(); 1287 if (argIndex < NumDataArgs) { 1288 // The check to see if the argIndex is valid will come later. 1289 // We set the bit here because we may exit early from this 1290 // function if we encounter some other error. 1291 CoveredArgs.set(argIndex); 1292 } 1293 1294 // Check for using an Objective-C specific conversion specifier 1295 // in a non-ObjC literal. 1296 if (!IsObjCLiteral && CS.isObjCArg()) { 1297 return HandleInvalidConversionSpecifier(FS, startSpecifier, specifierLen); 1298 } 1299 1300 // Are we using '%n'? Issue a warning about this being 1301 // a possible security issue. 1302 if (CS.getKind() == ConversionSpecifier::OutIntPtrArg) { 1303 S.Diag(getLocationOfByte(CS.getStart()), diag::warn_printf_write_back) 1304 << getFormatSpecifierRange(startSpecifier, specifierLen); 1305 // Continue checking the other format specifiers. 1306 return true; 1307 } 1308 1309 if (CS.getKind() == ConversionSpecifier::VoidPtrArg) { 1310 if (FS.getPrecision().getHowSpecified() != OptionalAmount::NotSpecified) 1311 S.Diag(getLocationOfByte(CS.getStart()), 1312 diag::warn_printf_nonsensical_precision) 1313 << CS.getCharacters() 1314 << getFormatSpecifierRange(startSpecifier, specifierLen); 1315 } 1316 if (CS.getKind() == ConversionSpecifier::VoidPtrArg || 1317 CS.getKind() == ConversionSpecifier::CStrArg) { 1318 // FIXME: Instead of using "0", "+", etc., eventually get them from 1319 // the FormatSpecifier. 1320 if (FS.hasLeadingZeros()) 1321 HandleFlags(FS, "0", CS.getCharacters(), startSpecifier, specifierLen); 1322 if (FS.hasPlusPrefix()) 1323 HandleFlags(FS, "+", CS.getCharacters(), startSpecifier, specifierLen); 1324 if (FS.hasSpacePrefix()) 1325 HandleFlags(FS, " ", CS.getCharacters(), startSpecifier, specifierLen); 1326 } 1327 1328 // The remaining checks depend on the data arguments. 1329 if (HasVAListArg) 1330 return true; 1331 1332 if (argIndex >= NumDataArgs) { 1333 S.Diag(getLocationOfByte(CS.getStart()), 1334 diag::warn_printf_insufficient_data_args) 1335 << getFormatSpecifierRange(startSpecifier, specifierLen); 1336 // Don't do any more checking. 1337 return false; 1338 } 1339 1340 // Now type check the data expression that matches the 1341 // format specifier. 1342 const Expr *Ex = getDataArg(argIndex); 1343 const analyze_printf::ArgTypeResult &ATR = FS.getArgType(S.Context); 1344 if (ATR.isValid() && !ATR.matchesType(S.Context, Ex->getType())) { 1345 // Check if we didn't match because of an implicit cast from a 'char' 1346 // or 'short' to an 'int'. This is done because printf is a varargs 1347 // function. 1348 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(Ex)) 1349 if (ICE->getType() == S.Context.IntTy) 1350 if (ATR.matchesType(S.Context, ICE->getSubExpr()->getType())) 1351 return true; 1352 1353 S.Diag(getLocationOfByte(CS.getStart()), 1354 diag::warn_printf_conversion_argument_type_mismatch) 1355 << ATR.getRepresentativeType(S.Context) << Ex->getType() 1356 << getFormatSpecifierRange(startSpecifier, specifierLen) 1357 << Ex->getSourceRange(); 1358 } 1359 1360 return true; 1361} 1362 1363void CheckPrintfHandler::DoneProcessing() { 1364 // Does the number of data arguments exceed the number of 1365 // format conversions in the format string? 1366 if (!HasVAListArg) { 1367 // Find any arguments that weren't covered. 1368 CoveredArgs.flip(); 1369 signed notCoveredArg = CoveredArgs.find_first(); 1370 if (notCoveredArg >= 0) { 1371 assert((unsigned)notCoveredArg < NumDataArgs); 1372 S.Diag(getDataArg((unsigned) notCoveredArg)->getLocStart(), 1373 diag::warn_printf_data_arg_not_used) 1374 << getFormatStringRange(); 1375 } 1376 } 1377} 1378 1379void Sema::CheckPrintfString(const StringLiteral *FExpr, 1380 const Expr *OrigFormatExpr, 1381 const CallExpr *TheCall, bool HasVAListArg, 1382 unsigned format_idx, unsigned firstDataArg) { 1383 1384 // CHECK: is the format string a wide literal? 1385 if (FExpr->isWide()) { 1386 Diag(FExpr->getLocStart(), 1387 diag::warn_printf_format_string_is_wide_literal) 1388 << OrigFormatExpr->getSourceRange(); 1389 return; 1390 } 1391 1392 // Str - The format string. NOTE: this is NOT null-terminated! 1393 const char *Str = FExpr->getStrData(); 1394 1395 // CHECK: empty format string? 1396 unsigned StrLen = FExpr->getByteLength(); 1397 1398 if (StrLen == 0) { 1399 Diag(FExpr->getLocStart(), diag::warn_printf_empty_format_string) 1400 << OrigFormatExpr->getSourceRange(); 1401 return; 1402 } 1403 1404 CheckPrintfHandler H(*this, FExpr, OrigFormatExpr, 1405 TheCall->getNumArgs() - firstDataArg, 1406 isa<ObjCStringLiteral>(OrigFormatExpr), Str, 1407 HasVAListArg, TheCall, format_idx); 1408 1409 if (!analyze_printf::ParseFormatString(H, Str, Str + StrLen)) 1410 H.DoneProcessing(); 1411} 1412 1413//===--- CHECK: Return Address of Stack Variable --------------------------===// 1414 1415static DeclRefExpr* EvalVal(Expr *E); 1416static DeclRefExpr* EvalAddr(Expr* E); 1417 1418/// CheckReturnStackAddr - Check if a return statement returns the address 1419/// of a stack variable. 1420void 1421Sema::CheckReturnStackAddr(Expr *RetValExp, QualType lhsType, 1422 SourceLocation ReturnLoc) { 1423 1424 // Perform checking for returned stack addresses. 1425 if (lhsType->isPointerType() || lhsType->isBlockPointerType()) { 1426 if (DeclRefExpr *DR = EvalAddr(RetValExp)) 1427 Diag(DR->getLocStart(), diag::warn_ret_stack_addr) 1428 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1429 1430 // Skip over implicit cast expressions when checking for block expressions. 1431 RetValExp = RetValExp->IgnoreParenCasts(); 1432 1433 if (BlockExpr *C = dyn_cast<BlockExpr>(RetValExp)) 1434 if (C->hasBlockDeclRefExprs()) 1435 Diag(C->getLocStart(), diag::err_ret_local_block) 1436 << C->getSourceRange(); 1437 1438 if (AddrLabelExpr *ALE = dyn_cast<AddrLabelExpr>(RetValExp)) 1439 Diag(ALE->getLocStart(), diag::warn_ret_addr_label) 1440 << ALE->getSourceRange(); 1441 1442 } else if (lhsType->isReferenceType()) { 1443 // Perform checking for stack values returned by reference. 1444 // Check for a reference to the stack 1445 if (DeclRefExpr *DR = EvalVal(RetValExp)) 1446 Diag(DR->getLocStart(), diag::warn_ret_stack_ref) 1447 << DR->getDecl()->getDeclName() << RetValExp->getSourceRange(); 1448 } 1449} 1450 1451/// EvalAddr - EvalAddr and EvalVal are mutually recursive functions that 1452/// check if the expression in a return statement evaluates to an address 1453/// to a location on the stack. The recursion is used to traverse the 1454/// AST of the return expression, with recursion backtracking when we 1455/// encounter a subexpression that (1) clearly does not lead to the address 1456/// of a stack variable or (2) is something we cannot determine leads to 1457/// the address of a stack variable based on such local checking. 1458/// 1459/// EvalAddr processes expressions that are pointers that are used as 1460/// references (and not L-values). EvalVal handles all other values. 1461/// At the base case of the recursion is a check for a DeclRefExpr* in 1462/// the refers to a stack variable. 1463/// 1464/// This implementation handles: 1465/// 1466/// * pointer-to-pointer casts 1467/// * implicit conversions from array references to pointers 1468/// * taking the address of fields 1469/// * arbitrary interplay between "&" and "*" operators 1470/// * pointer arithmetic from an address of a stack variable 1471/// * taking the address of an array element where the array is on the stack 1472static DeclRefExpr* EvalAddr(Expr *E) { 1473 // We should only be called for evaluating pointer expressions. 1474 assert((E->getType()->isAnyPointerType() || 1475 E->getType()->isBlockPointerType() || 1476 E->getType()->isObjCQualifiedIdType()) && 1477 "EvalAddr only works on pointers"); 1478 1479 // Our "symbolic interpreter" is just a dispatch off the currently 1480 // viewed AST node. We then recursively traverse the AST by calling 1481 // EvalAddr and EvalVal appropriately. 1482 switch (E->getStmtClass()) { 1483 case Stmt::ParenExprClass: 1484 // Ignore parentheses. 1485 return EvalAddr(cast<ParenExpr>(E)->getSubExpr()); 1486 1487 case Stmt::UnaryOperatorClass: { 1488 // The only unary operator that make sense to handle here 1489 // is AddrOf. All others don't make sense as pointers. 1490 UnaryOperator *U = cast<UnaryOperator>(E); 1491 1492 if (U->getOpcode() == UnaryOperator::AddrOf) 1493 return EvalVal(U->getSubExpr()); 1494 else 1495 return NULL; 1496 } 1497 1498 case Stmt::BinaryOperatorClass: { 1499 // Handle pointer arithmetic. All other binary operators are not valid 1500 // in this context. 1501 BinaryOperator *B = cast<BinaryOperator>(E); 1502 BinaryOperator::Opcode op = B->getOpcode(); 1503 1504 if (op != BinaryOperator::Add && op != BinaryOperator::Sub) 1505 return NULL; 1506 1507 Expr *Base = B->getLHS(); 1508 1509 // Determine which argument is the real pointer base. It could be 1510 // the RHS argument instead of the LHS. 1511 if (!Base->getType()->isPointerType()) Base = B->getRHS(); 1512 1513 assert (Base->getType()->isPointerType()); 1514 return EvalAddr(Base); 1515 } 1516 1517 // For conditional operators we need to see if either the LHS or RHS are 1518 // valid DeclRefExpr*s. If one of them is valid, we return it. 1519 case Stmt::ConditionalOperatorClass: { 1520 ConditionalOperator *C = cast<ConditionalOperator>(E); 1521 1522 // Handle the GNU extension for missing LHS. 1523 if (Expr *lhsExpr = C->getLHS()) 1524 if (DeclRefExpr* LHS = EvalAddr(lhsExpr)) 1525 return LHS; 1526 1527 return EvalAddr(C->getRHS()); 1528 } 1529 1530 // For casts, we need to handle conversions from arrays to 1531 // pointer values, and pointer-to-pointer conversions. 1532 case Stmt::ImplicitCastExprClass: 1533 case Stmt::CStyleCastExprClass: 1534 case Stmt::CXXFunctionalCastExprClass: { 1535 Expr* SubExpr = cast<CastExpr>(E)->getSubExpr(); 1536 QualType T = SubExpr->getType(); 1537 1538 if (SubExpr->getType()->isPointerType() || 1539 SubExpr->getType()->isBlockPointerType() || 1540 SubExpr->getType()->isObjCQualifiedIdType()) 1541 return EvalAddr(SubExpr); 1542 else if (T->isArrayType()) 1543 return EvalVal(SubExpr); 1544 else 1545 return 0; 1546 } 1547 1548 // C++ casts. For dynamic casts, static casts, and const casts, we 1549 // are always converting from a pointer-to-pointer, so we just blow 1550 // through the cast. In the case the dynamic cast doesn't fail (and 1551 // return NULL), we take the conservative route and report cases 1552 // where we return the address of a stack variable. For Reinterpre 1553 // FIXME: The comment about is wrong; we're not always converting 1554 // from pointer to pointer. I'm guessing that this code should also 1555 // handle references to objects. 1556 case Stmt::CXXStaticCastExprClass: 1557 case Stmt::CXXDynamicCastExprClass: 1558 case Stmt::CXXConstCastExprClass: 1559 case Stmt::CXXReinterpretCastExprClass: { 1560 Expr *S = cast<CXXNamedCastExpr>(E)->getSubExpr(); 1561 if (S->getType()->isPointerType() || S->getType()->isBlockPointerType()) 1562 return EvalAddr(S); 1563 else 1564 return NULL; 1565 } 1566 1567 // Everything else: we simply don't reason about them. 1568 default: 1569 return NULL; 1570 } 1571} 1572 1573 1574/// EvalVal - This function is complements EvalAddr in the mutual recursion. 1575/// See the comments for EvalAddr for more details. 1576static DeclRefExpr* EvalVal(Expr *E) { 1577 1578 // We should only be called for evaluating non-pointer expressions, or 1579 // expressions with a pointer type that are not used as references but instead 1580 // are l-values (e.g., DeclRefExpr with a pointer type). 1581 1582 // Our "symbolic interpreter" is just a dispatch off the currently 1583 // viewed AST node. We then recursively traverse the AST by calling 1584 // EvalAddr and EvalVal appropriately. 1585 switch (E->getStmtClass()) { 1586 case Stmt::DeclRefExprClass: { 1587 // DeclRefExpr: the base case. When we hit a DeclRefExpr we are looking 1588 // at code that refers to a variable's name. We check if it has local 1589 // storage within the function, and if so, return the expression. 1590 DeclRefExpr *DR = cast<DeclRefExpr>(E); 1591 1592 if (VarDecl *V = dyn_cast<VarDecl>(DR->getDecl())) 1593 if (V->hasLocalStorage() && !V->getType()->isReferenceType()) return DR; 1594 1595 return NULL; 1596 } 1597 1598 case Stmt::ParenExprClass: 1599 // Ignore parentheses. 1600 return EvalVal(cast<ParenExpr>(E)->getSubExpr()); 1601 1602 case Stmt::UnaryOperatorClass: { 1603 // The only unary operator that make sense to handle here 1604 // is Deref. All others don't resolve to a "name." This includes 1605 // handling all sorts of rvalues passed to a unary operator. 1606 UnaryOperator *U = cast<UnaryOperator>(E); 1607 1608 if (U->getOpcode() == UnaryOperator::Deref) 1609 return EvalAddr(U->getSubExpr()); 1610 1611 return NULL; 1612 } 1613 1614 case Stmt::ArraySubscriptExprClass: { 1615 // Array subscripts are potential references to data on the stack. We 1616 // retrieve the DeclRefExpr* for the array variable if it indeed 1617 // has local storage. 1618 return EvalAddr(cast<ArraySubscriptExpr>(E)->getBase()); 1619 } 1620 1621 case Stmt::ConditionalOperatorClass: { 1622 // For conditional operators we need to see if either the LHS or RHS are 1623 // non-NULL DeclRefExpr's. If one is non-NULL, we return it. 1624 ConditionalOperator *C = cast<ConditionalOperator>(E); 1625 1626 // Handle the GNU extension for missing LHS. 1627 if (Expr *lhsExpr = C->getLHS()) 1628 if (DeclRefExpr *LHS = EvalVal(lhsExpr)) 1629 return LHS; 1630 1631 return EvalVal(C->getRHS()); 1632 } 1633 1634 // Accesses to members are potential references to data on the stack. 1635 case Stmt::MemberExprClass: { 1636 MemberExpr *M = cast<MemberExpr>(E); 1637 1638 // Check for indirect access. We only want direct field accesses. 1639 if (!M->isArrow()) 1640 return EvalVal(M->getBase()); 1641 else 1642 return NULL; 1643 } 1644 1645 // Everything else: we simply don't reason about them. 1646 default: 1647 return NULL; 1648 } 1649} 1650 1651//===--- CHECK: Floating-Point comparisons (-Wfloat-equal) ---------------===// 1652 1653/// Check for comparisons of floating point operands using != and ==. 1654/// Issue a warning if these are no self-comparisons, as they are not likely 1655/// to do what the programmer intended. 1656void Sema::CheckFloatComparison(SourceLocation loc, Expr* lex, Expr *rex) { 1657 bool EmitWarning = true; 1658 1659 Expr* LeftExprSansParen = lex->IgnoreParens(); 1660 Expr* RightExprSansParen = rex->IgnoreParens(); 1661 1662 // Special case: check for x == x (which is OK). 1663 // Do not emit warnings for such cases. 1664 if (DeclRefExpr* DRL = dyn_cast<DeclRefExpr>(LeftExprSansParen)) 1665 if (DeclRefExpr* DRR = dyn_cast<DeclRefExpr>(RightExprSansParen)) 1666 if (DRL->getDecl() == DRR->getDecl()) 1667 EmitWarning = false; 1668 1669 1670 // Special case: check for comparisons against literals that can be exactly 1671 // represented by APFloat. In such cases, do not emit a warning. This 1672 // is a heuristic: often comparison against such literals are used to 1673 // detect if a value in a variable has not changed. This clearly can 1674 // lead to false negatives. 1675 if (EmitWarning) { 1676 if (FloatingLiteral* FLL = dyn_cast<FloatingLiteral>(LeftExprSansParen)) { 1677 if (FLL->isExact()) 1678 EmitWarning = false; 1679 } else 1680 if (FloatingLiteral* FLR = dyn_cast<FloatingLiteral>(RightExprSansParen)){ 1681 if (FLR->isExact()) 1682 EmitWarning = false; 1683 } 1684 } 1685 1686 // Check for comparisons with builtin types. 1687 if (EmitWarning) 1688 if (CallExpr* CL = dyn_cast<CallExpr>(LeftExprSansParen)) 1689 if (CL->isBuiltinCall(Context)) 1690 EmitWarning = false; 1691 1692 if (EmitWarning) 1693 if (CallExpr* CR = dyn_cast<CallExpr>(RightExprSansParen)) 1694 if (CR->isBuiltinCall(Context)) 1695 EmitWarning = false; 1696 1697 // Emit the diagnostic. 1698 if (EmitWarning) 1699 Diag(loc, diag::warn_floatingpoint_eq) 1700 << lex->getSourceRange() << rex->getSourceRange(); 1701} 1702 1703//===--- CHECK: Integer mixed-sign comparisons (-Wsign-compare) --------===// 1704//===--- CHECK: Lossy implicit conversions (-Wconversion) --------------===// 1705 1706namespace { 1707 1708/// Structure recording the 'active' range of an integer-valued 1709/// expression. 1710struct IntRange { 1711 /// The number of bits active in the int. 1712 unsigned Width; 1713 1714 /// True if the int is known not to have negative values. 1715 bool NonNegative; 1716 1717 IntRange() {} 1718 IntRange(unsigned Width, bool NonNegative) 1719 : Width(Width), NonNegative(NonNegative) 1720 {} 1721 1722 // Returns the range of the bool type. 1723 static IntRange forBoolType() { 1724 return IntRange(1, true); 1725 } 1726 1727 // Returns the range of an integral type. 1728 static IntRange forType(ASTContext &C, QualType T) { 1729 return forCanonicalType(C, T->getCanonicalTypeInternal().getTypePtr()); 1730 } 1731 1732 // Returns the range of an integeral type based on its canonical 1733 // representation. 1734 static IntRange forCanonicalType(ASTContext &C, const Type *T) { 1735 assert(T->isCanonicalUnqualified()); 1736 1737 if (const VectorType *VT = dyn_cast<VectorType>(T)) 1738 T = VT->getElementType().getTypePtr(); 1739 if (const ComplexType *CT = dyn_cast<ComplexType>(T)) 1740 T = CT->getElementType().getTypePtr(); 1741 if (const EnumType *ET = dyn_cast<EnumType>(T)) 1742 T = ET->getDecl()->getIntegerType().getTypePtr(); 1743 1744 const BuiltinType *BT = cast<BuiltinType>(T); 1745 assert(BT->isInteger()); 1746 1747 return IntRange(C.getIntWidth(QualType(T, 0)), BT->isUnsignedInteger()); 1748 } 1749 1750 // Returns the supremum of two ranges: i.e. their conservative merge. 1751 static IntRange join(IntRange L, IntRange R) { 1752 return IntRange(std::max(L.Width, R.Width), 1753 L.NonNegative && R.NonNegative); 1754 } 1755 1756 // Returns the infinum of two ranges: i.e. their aggressive merge. 1757 static IntRange meet(IntRange L, IntRange R) { 1758 return IntRange(std::min(L.Width, R.Width), 1759 L.NonNegative || R.NonNegative); 1760 } 1761}; 1762 1763IntRange GetValueRange(ASTContext &C, llvm::APSInt &value, unsigned MaxWidth) { 1764 if (value.isSigned() && value.isNegative()) 1765 return IntRange(value.getMinSignedBits(), false); 1766 1767 if (value.getBitWidth() > MaxWidth) 1768 value.trunc(MaxWidth); 1769 1770 // isNonNegative() just checks the sign bit without considering 1771 // signedness. 1772 return IntRange(value.getActiveBits(), true); 1773} 1774 1775IntRange GetValueRange(ASTContext &C, APValue &result, QualType Ty, 1776 unsigned MaxWidth) { 1777 if (result.isInt()) 1778 return GetValueRange(C, result.getInt(), MaxWidth); 1779 1780 if (result.isVector()) { 1781 IntRange R = GetValueRange(C, result.getVectorElt(0), Ty, MaxWidth); 1782 for (unsigned i = 1, e = result.getVectorLength(); i != e; ++i) { 1783 IntRange El = GetValueRange(C, result.getVectorElt(i), Ty, MaxWidth); 1784 R = IntRange::join(R, El); 1785 } 1786 return R; 1787 } 1788 1789 if (result.isComplexInt()) { 1790 IntRange R = GetValueRange(C, result.getComplexIntReal(), MaxWidth); 1791 IntRange I = GetValueRange(C, result.getComplexIntImag(), MaxWidth); 1792 return IntRange::join(R, I); 1793 } 1794 1795 // This can happen with lossless casts to intptr_t of "based" lvalues. 1796 // Assume it might use arbitrary bits. 1797 // FIXME: The only reason we need to pass the type in here is to get 1798 // the sign right on this one case. It would be nice if APValue 1799 // preserved this. 1800 assert(result.isLValue()); 1801 return IntRange(MaxWidth, Ty->isUnsignedIntegerType()); 1802} 1803 1804/// Pseudo-evaluate the given integer expression, estimating the 1805/// range of values it might take. 1806/// 1807/// \param MaxWidth - the width to which the value will be truncated 1808IntRange GetExprRange(ASTContext &C, Expr *E, unsigned MaxWidth) { 1809 E = E->IgnoreParens(); 1810 1811 // Try a full evaluation first. 1812 Expr::EvalResult result; 1813 if (E->Evaluate(result, C)) 1814 return GetValueRange(C, result.Val, E->getType(), MaxWidth); 1815 1816 // I think we only want to look through implicit casts here; if the 1817 // user has an explicit widening cast, we should treat the value as 1818 // being of the new, wider type. 1819 if (ImplicitCastExpr *CE = dyn_cast<ImplicitCastExpr>(E)) { 1820 if (CE->getCastKind() == CastExpr::CK_NoOp) 1821 return GetExprRange(C, CE->getSubExpr(), MaxWidth); 1822 1823 IntRange OutputTypeRange = IntRange::forType(C, CE->getType()); 1824 1825 bool isIntegerCast = (CE->getCastKind() == CastExpr::CK_IntegralCast); 1826 if (!isIntegerCast && CE->getCastKind() == CastExpr::CK_Unknown) 1827 isIntegerCast = CE->getSubExpr()->getType()->isIntegerType(); 1828 1829 // Assume that non-integer casts can span the full range of the type. 1830 if (!isIntegerCast) 1831 return OutputTypeRange; 1832 1833 IntRange SubRange 1834 = GetExprRange(C, CE->getSubExpr(), 1835 std::min(MaxWidth, OutputTypeRange.Width)); 1836 1837 // Bail out if the subexpr's range is as wide as the cast type. 1838 if (SubRange.Width >= OutputTypeRange.Width) 1839 return OutputTypeRange; 1840 1841 // Otherwise, we take the smaller width, and we're non-negative if 1842 // either the output type or the subexpr is. 1843 return IntRange(SubRange.Width, 1844 SubRange.NonNegative || OutputTypeRange.NonNegative); 1845 } 1846 1847 if (ConditionalOperator *CO = dyn_cast<ConditionalOperator>(E)) { 1848 // If we can fold the condition, just take that operand. 1849 bool CondResult; 1850 if (CO->getCond()->EvaluateAsBooleanCondition(CondResult, C)) 1851 return GetExprRange(C, CondResult ? CO->getTrueExpr() 1852 : CO->getFalseExpr(), 1853 MaxWidth); 1854 1855 // Otherwise, conservatively merge. 1856 IntRange L = GetExprRange(C, CO->getTrueExpr(), MaxWidth); 1857 IntRange R = GetExprRange(C, CO->getFalseExpr(), MaxWidth); 1858 return IntRange::join(L, R); 1859 } 1860 1861 if (BinaryOperator *BO = dyn_cast<BinaryOperator>(E)) { 1862 switch (BO->getOpcode()) { 1863 1864 // Boolean-valued operations are single-bit and positive. 1865 case BinaryOperator::LAnd: 1866 case BinaryOperator::LOr: 1867 case BinaryOperator::LT: 1868 case BinaryOperator::GT: 1869 case BinaryOperator::LE: 1870 case BinaryOperator::GE: 1871 case BinaryOperator::EQ: 1872 case BinaryOperator::NE: 1873 return IntRange::forBoolType(); 1874 1875 // The type of these compound assignments is the type of the LHS, 1876 // so the RHS is not necessarily an integer. 1877 case BinaryOperator::MulAssign: 1878 case BinaryOperator::DivAssign: 1879 case BinaryOperator::RemAssign: 1880 case BinaryOperator::AddAssign: 1881 case BinaryOperator::SubAssign: 1882 return IntRange::forType(C, E->getType()); 1883 1884 // Operations with opaque sources are black-listed. 1885 case BinaryOperator::PtrMemD: 1886 case BinaryOperator::PtrMemI: 1887 return IntRange::forType(C, E->getType()); 1888 1889 // Bitwise-and uses the *infinum* of the two source ranges. 1890 case BinaryOperator::And: 1891 case BinaryOperator::AndAssign: 1892 return IntRange::meet(GetExprRange(C, BO->getLHS(), MaxWidth), 1893 GetExprRange(C, BO->getRHS(), MaxWidth)); 1894 1895 // Left shift gets black-listed based on a judgement call. 1896 case BinaryOperator::Shl: 1897 case BinaryOperator::ShlAssign: 1898 return IntRange::forType(C, E->getType()); 1899 1900 // Right shift by a constant can narrow its left argument. 1901 case BinaryOperator::Shr: 1902 case BinaryOperator::ShrAssign: { 1903 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 1904 1905 // If the shift amount is a positive constant, drop the width by 1906 // that much. 1907 llvm::APSInt shift; 1908 if (BO->getRHS()->isIntegerConstantExpr(shift, C) && 1909 shift.isNonNegative()) { 1910 unsigned zext = shift.getZExtValue(); 1911 if (zext >= L.Width) 1912 L.Width = (L.NonNegative ? 0 : 1); 1913 else 1914 L.Width -= zext; 1915 } 1916 1917 return L; 1918 } 1919 1920 // Comma acts as its right operand. 1921 case BinaryOperator::Comma: 1922 return GetExprRange(C, BO->getRHS(), MaxWidth); 1923 1924 // Black-list pointer subtractions. 1925 case BinaryOperator::Sub: 1926 if (BO->getLHS()->getType()->isPointerType()) 1927 return IntRange::forType(C, E->getType()); 1928 // fallthrough 1929 1930 default: 1931 break; 1932 } 1933 1934 // Treat every other operator as if it were closed on the 1935 // narrowest type that encompasses both operands. 1936 IntRange L = GetExprRange(C, BO->getLHS(), MaxWidth); 1937 IntRange R = GetExprRange(C, BO->getRHS(), MaxWidth); 1938 return IntRange::join(L, R); 1939 } 1940 1941 if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E)) { 1942 switch (UO->getOpcode()) { 1943 // Boolean-valued operations are white-listed. 1944 case UnaryOperator::LNot: 1945 return IntRange::forBoolType(); 1946 1947 // Operations with opaque sources are black-listed. 1948 case UnaryOperator::Deref: 1949 case UnaryOperator::AddrOf: // should be impossible 1950 case UnaryOperator::OffsetOf: 1951 return IntRange::forType(C, E->getType()); 1952 1953 default: 1954 return GetExprRange(C, UO->getSubExpr(), MaxWidth); 1955 } 1956 } 1957 1958 FieldDecl *BitField = E->getBitField(); 1959 if (BitField) { 1960 llvm::APSInt BitWidthAP = BitField->getBitWidth()->EvaluateAsInt(C); 1961 unsigned BitWidth = BitWidthAP.getZExtValue(); 1962 1963 return IntRange(BitWidth, BitField->getType()->isUnsignedIntegerType()); 1964 } 1965 1966 return IntRange::forType(C, E->getType()); 1967} 1968 1969/// Checks whether the given value, which currently has the given 1970/// source semantics, has the same value when coerced through the 1971/// target semantics. 1972bool IsSameFloatAfterCast(const llvm::APFloat &value, 1973 const llvm::fltSemantics &Src, 1974 const llvm::fltSemantics &Tgt) { 1975 llvm::APFloat truncated = value; 1976 1977 bool ignored; 1978 truncated.convert(Src, llvm::APFloat::rmNearestTiesToEven, &ignored); 1979 truncated.convert(Tgt, llvm::APFloat::rmNearestTiesToEven, &ignored); 1980 1981 return truncated.bitwiseIsEqual(value); 1982} 1983 1984/// Checks whether the given value, which currently has the given 1985/// source semantics, has the same value when coerced through the 1986/// target semantics. 1987/// 1988/// The value might be a vector of floats (or a complex number). 1989bool IsSameFloatAfterCast(const APValue &value, 1990 const llvm::fltSemantics &Src, 1991 const llvm::fltSemantics &Tgt) { 1992 if (value.isFloat()) 1993 return IsSameFloatAfterCast(value.getFloat(), Src, Tgt); 1994 1995 if (value.isVector()) { 1996 for (unsigned i = 0, e = value.getVectorLength(); i != e; ++i) 1997 if (!IsSameFloatAfterCast(value.getVectorElt(i), Src, Tgt)) 1998 return false; 1999 return true; 2000 } 2001 2002 assert(value.isComplexFloat()); 2003 return (IsSameFloatAfterCast(value.getComplexFloatReal(), Src, Tgt) && 2004 IsSameFloatAfterCast(value.getComplexFloatImag(), Src, Tgt)); 2005} 2006 2007} // end anonymous namespace 2008 2009/// \brief Implements -Wsign-compare. 2010/// 2011/// \param lex the left-hand expression 2012/// \param rex the right-hand expression 2013/// \param OpLoc the location of the joining operator 2014/// \param BinOpc binary opcode or 0 2015void Sema::CheckSignCompare(Expr *lex, Expr *rex, SourceLocation OpLoc, 2016 const BinaryOperator::Opcode* BinOpc) { 2017 // Don't warn if we're in an unevaluated context. 2018 if (ExprEvalContexts.back().Context == Unevaluated) 2019 return; 2020 2021 // If either expression is value-dependent, don't warn. We'll get another 2022 // chance at instantiation time. 2023 if (lex->isValueDependent() || rex->isValueDependent()) 2024 return; 2025 2026 QualType lt = lex->getType(), rt = rex->getType(); 2027 2028 // Only warn if both operands are integral. 2029 if (!lt->isIntegerType() || !rt->isIntegerType()) 2030 return; 2031 2032 // In C, the width of a bitfield determines its type, and the 2033 // declared type only contributes the signedness. This duplicates 2034 // the work that will later be done by UsualUnaryConversions. 2035 // Eventually, this check will be reorganized in a way that avoids 2036 // this duplication. 2037 if (!getLangOptions().CPlusPlus) { 2038 QualType tmp; 2039 tmp = Context.isPromotableBitField(lex); 2040 if (!tmp.isNull()) lt = tmp; 2041 tmp = Context.isPromotableBitField(rex); 2042 if (!tmp.isNull()) rt = tmp; 2043 } 2044 2045 // The rule is that the signed operand becomes unsigned, so isolate the 2046 // signed operand. 2047 Expr *signedOperand = lex, *unsignedOperand = rex; 2048 QualType signedType = lt, unsignedType = rt; 2049 if (lt->isSignedIntegerType()) { 2050 if (rt->isSignedIntegerType()) return; 2051 } else { 2052 if (!rt->isSignedIntegerType()) return; 2053 std::swap(signedOperand, unsignedOperand); 2054 std::swap(signedType, unsignedType); 2055 } 2056 2057 unsigned unsignedWidth = Context.getIntWidth(unsignedType); 2058 unsigned signedWidth = Context.getIntWidth(signedType); 2059 2060 // If the unsigned type is strictly smaller than the signed type, 2061 // then (1) the result type will be signed and (2) the unsigned 2062 // value will fit fully within the signed type, and thus the result 2063 // of the comparison will be exact. 2064 if (signedWidth > unsignedWidth) 2065 return; 2066 2067 // Otherwise, calculate the effective ranges. 2068 IntRange signedRange = GetExprRange(Context, signedOperand, signedWidth); 2069 IntRange unsignedRange = GetExprRange(Context, unsignedOperand, unsignedWidth); 2070 2071 // We should never be unable to prove that the unsigned operand is 2072 // non-negative. 2073 assert(unsignedRange.NonNegative && "unsigned range includes negative?"); 2074 2075 // If the signed operand is non-negative, then the signed->unsigned 2076 // conversion won't change it. 2077 if (signedRange.NonNegative) { 2078 // Emit warnings for comparisons of unsigned to integer constant 0. 2079 // always false: x < 0 (or 0 > x) 2080 // always true: x >= 0 (or 0 <= x) 2081 llvm::APSInt X; 2082 if (BinOpc && signedOperand->isIntegerConstantExpr(X, Context) && X == 0) { 2083 if (signedOperand != lex) { 2084 if (*BinOpc == BinaryOperator::LT) { 2085 Diag(OpLoc, diag::warn_lunsigned_always_true_comparison) 2086 << "< 0" << "false" 2087 << lex->getSourceRange() << rex->getSourceRange(); 2088 } 2089 else if (*BinOpc == BinaryOperator::GE) { 2090 Diag(OpLoc, diag::warn_lunsigned_always_true_comparison) 2091 << ">= 0" << "true" 2092 << lex->getSourceRange() << rex->getSourceRange(); 2093 } 2094 } 2095 else { 2096 if (*BinOpc == BinaryOperator::GT) { 2097 Diag(OpLoc, diag::warn_runsigned_always_true_comparison) 2098 << "0 >" << "false" 2099 << lex->getSourceRange() << rex->getSourceRange(); 2100 } 2101 else if (*BinOpc == BinaryOperator::LE) { 2102 Diag(OpLoc, diag::warn_runsigned_always_true_comparison) 2103 << "0 <=" << "true" 2104 << lex->getSourceRange() << rex->getSourceRange(); 2105 } 2106 } 2107 } 2108 return; 2109 } 2110 2111 // For (in)equality comparisons, if the unsigned operand is a 2112 // constant which cannot collide with a overflowed signed operand, 2113 // then reinterpreting the signed operand as unsigned will not 2114 // change the result of the comparison. 2115 if (BinOpc && 2116 (*BinOpc == BinaryOperator::EQ || *BinOpc == BinaryOperator::NE) && 2117 unsignedRange.Width < unsignedWidth) 2118 return; 2119 2120 Diag(OpLoc, BinOpc ? diag::warn_mixed_sign_comparison 2121 : diag::warn_mixed_sign_conditional) 2122 << lt << rt << lex->getSourceRange() << rex->getSourceRange(); 2123} 2124 2125/// Diagnose an implicit cast; purely a helper for CheckImplicitConversion. 2126static void DiagnoseImpCast(Sema &S, Expr *E, QualType T, unsigned diag) { 2127 S.Diag(E->getExprLoc(), diag) << E->getType() << T << E->getSourceRange(); 2128} 2129 2130/// Implements -Wconversion. 2131void Sema::CheckImplicitConversion(Expr *E, QualType T) { 2132 // Don't diagnose in unevaluated contexts. 2133 if (ExprEvalContexts.back().Context == Sema::Unevaluated) 2134 return; 2135 2136 // Don't diagnose for value-dependent expressions. 2137 if (E->isValueDependent()) 2138 return; 2139 2140 const Type *Source = Context.getCanonicalType(E->getType()).getTypePtr(); 2141 const Type *Target = Context.getCanonicalType(T).getTypePtr(); 2142 2143 // Never diagnose implicit casts to bool. 2144 if (Target->isSpecificBuiltinType(BuiltinType::Bool)) 2145 return; 2146 2147 // Strip vector types. 2148 if (isa<VectorType>(Source)) { 2149 if (!isa<VectorType>(Target)) 2150 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_vector_scalar); 2151 2152 Source = cast<VectorType>(Source)->getElementType().getTypePtr(); 2153 Target = cast<VectorType>(Target)->getElementType().getTypePtr(); 2154 } 2155 2156 // Strip complex types. 2157 if (isa<ComplexType>(Source)) { 2158 if (!isa<ComplexType>(Target)) 2159 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_complex_scalar); 2160 2161 Source = cast<ComplexType>(Source)->getElementType().getTypePtr(); 2162 Target = cast<ComplexType>(Target)->getElementType().getTypePtr(); 2163 } 2164 2165 const BuiltinType *SourceBT = dyn_cast<BuiltinType>(Source); 2166 const BuiltinType *TargetBT = dyn_cast<BuiltinType>(Target); 2167 2168 // If the source is floating point... 2169 if (SourceBT && SourceBT->isFloatingPoint()) { 2170 // ...and the target is floating point... 2171 if (TargetBT && TargetBT->isFloatingPoint()) { 2172 // ...then warn if we're dropping FP rank. 2173 2174 // Builtin FP kinds are ordered by increasing FP rank. 2175 if (SourceBT->getKind() > TargetBT->getKind()) { 2176 // Don't warn about float constants that are precisely 2177 // representable in the target type. 2178 Expr::EvalResult result; 2179 if (E->Evaluate(result, Context)) { 2180 // Value might be a float, a float vector, or a float complex. 2181 if (IsSameFloatAfterCast(result.Val, 2182 Context.getFloatTypeSemantics(QualType(TargetBT, 0)), 2183 Context.getFloatTypeSemantics(QualType(SourceBT, 0)))) 2184 return; 2185 } 2186 2187 DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_precision); 2188 } 2189 return; 2190 } 2191 2192 // If the target is integral, always warn. 2193 if ((TargetBT && TargetBT->isInteger())) 2194 // TODO: don't warn for integer values? 2195 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_float_integer); 2196 2197 return; 2198 } 2199 2200 if (!Source->isIntegerType() || !Target->isIntegerType()) 2201 return; 2202 2203 IntRange SourceRange = GetExprRange(Context, E, Context.getIntWidth(E->getType())); 2204 IntRange TargetRange = IntRange::forCanonicalType(Context, Target); 2205 2206 // FIXME: also signed<->unsigned? 2207 2208 if (SourceRange.Width > TargetRange.Width) { 2209 // People want to build with -Wshorten-64-to-32 and not -Wconversion 2210 // and by god we'll let them. 2211 if (SourceRange.Width == 64 && TargetRange.Width == 32) 2212 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_64_32); 2213 return DiagnoseImpCast(*this, E, T, diag::warn_impcast_integer_precision); 2214 } 2215 2216 return; 2217} 2218 2219 2220 2221namespace { 2222class UnreachableCodeHandler : public reachable_code::Callback { 2223 Sema &S; 2224public: 2225 UnreachableCodeHandler(Sema *s) : S(*s) {} 2226 2227 void HandleUnreachable(SourceLocation L, SourceRange R1, SourceRange R2) { 2228 S.Diag(L, diag::warn_unreachable) << R1 << R2; 2229 } 2230}; 2231} 2232 2233/// CheckUnreachable - Check for unreachable code. 2234void Sema::CheckUnreachable(AnalysisContext &AC) { 2235 // We avoid checking when there are errors, as the CFG won't faithfully match 2236 // the user's code. 2237 if (getDiagnostics().hasErrorOccurred() || 2238 Diags.getDiagnosticLevel(diag::warn_unreachable) == Diagnostic::Ignored) 2239 return; 2240 2241 UnreachableCodeHandler UC(this); 2242 reachable_code::FindUnreachableCode(AC, UC); 2243} 2244 2245/// CheckFallThrough - Check that we don't fall off the end of a 2246/// Statement that should return a value. 2247/// 2248/// \returns AlwaysFallThrough iff we always fall off the end of the statement, 2249/// MaybeFallThrough iff we might or might not fall off the end, 2250/// NeverFallThroughOrReturn iff we never fall off the end of the statement or 2251/// return. We assume NeverFallThrough iff we never fall off the end of the 2252/// statement but we may return. We assume that functions not marked noreturn 2253/// will return. 2254Sema::ControlFlowKind Sema::CheckFallThrough(AnalysisContext &AC) { 2255 CFG *cfg = AC.getCFG(); 2256 if (cfg == 0) 2257 // FIXME: This should be NeverFallThrough 2258 return NeverFallThroughOrReturn; 2259 2260 // The CFG leaves in dead things, and we don't want the dead code paths to 2261 // confuse us, so we mark all live things first. 2262 std::queue<CFGBlock*> workq; 2263 llvm::BitVector live(cfg->getNumBlockIDs()); 2264 unsigned count = reachable_code::ScanReachableFromBlock(cfg->getEntry(), 2265 live); 2266 2267 bool AddEHEdges = AC.getAddEHEdges(); 2268 if (!AddEHEdges && count != cfg->getNumBlockIDs()) 2269 // When there are things remaining dead, and we didn't add EH edges 2270 // from CallExprs to the catch clauses, we have to go back and 2271 // mark them as live. 2272 for (CFG::iterator I = cfg->begin(), E = cfg->end(); I != E; ++I) { 2273 CFGBlock &b = **I; 2274 if (!live[b.getBlockID()]) { 2275 if (b.pred_begin() == b.pred_end()) { 2276 if (b.getTerminator() && isa<CXXTryStmt>(b.getTerminator())) 2277 // When not adding EH edges from calls, catch clauses 2278 // can otherwise seem dead. Avoid noting them as dead. 2279 count += reachable_code::ScanReachableFromBlock(b, live); 2280 continue; 2281 } 2282 } 2283 } 2284 2285 // Now we know what is live, we check the live precessors of the exit block 2286 // and look for fall through paths, being careful to ignore normal returns, 2287 // and exceptional paths. 2288 bool HasLiveReturn = false; 2289 bool HasFakeEdge = false; 2290 bool HasPlainEdge = false; 2291 bool HasAbnormalEdge = false; 2292 for (CFGBlock::pred_iterator I=cfg->getExit().pred_begin(), 2293 E = cfg->getExit().pred_end(); 2294 I != E; 2295 ++I) { 2296 CFGBlock& B = **I; 2297 if (!live[B.getBlockID()]) 2298 continue; 2299 if (B.size() == 0) { 2300 if (B.getTerminator() && isa<CXXTryStmt>(B.getTerminator())) { 2301 HasAbnormalEdge = true; 2302 continue; 2303 } 2304 2305 // A labeled empty statement, or the entry block... 2306 HasPlainEdge = true; 2307 continue; 2308 } 2309 Stmt *S = B[B.size()-1]; 2310 if (isa<ReturnStmt>(S)) { 2311 HasLiveReturn = true; 2312 continue; 2313 } 2314 if (isa<ObjCAtThrowStmt>(S)) { 2315 HasFakeEdge = true; 2316 continue; 2317 } 2318 if (isa<CXXThrowExpr>(S)) { 2319 HasFakeEdge = true; 2320 continue; 2321 } 2322 if (const AsmStmt *AS = dyn_cast<AsmStmt>(S)) { 2323 if (AS->isMSAsm()) { 2324 HasFakeEdge = true; 2325 HasLiveReturn = true; 2326 continue; 2327 } 2328 } 2329 if (isa<CXXTryStmt>(S)) { 2330 HasAbnormalEdge = true; 2331 continue; 2332 } 2333 2334 bool NoReturnEdge = false; 2335 if (CallExpr *C = dyn_cast<CallExpr>(S)) { 2336 if (B.succ_begin()[0] != &cfg->getExit()) { 2337 HasAbnormalEdge = true; 2338 continue; 2339 } 2340 Expr *CEE = C->getCallee()->IgnoreParenCasts(); 2341 if (CEE->getType().getNoReturnAttr()) { 2342 NoReturnEdge = true; 2343 HasFakeEdge = true; 2344 } else if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(CEE)) { 2345 ValueDecl *VD = DRE->getDecl(); 2346 if (VD->hasAttr<NoReturnAttr>()) { 2347 NoReturnEdge = true; 2348 HasFakeEdge = true; 2349 } 2350 } 2351 } 2352 // FIXME: Add noreturn message sends. 2353 if (NoReturnEdge == false) 2354 HasPlainEdge = true; 2355 } 2356 if (!HasPlainEdge) { 2357 if (HasLiveReturn) 2358 return NeverFallThrough; 2359 return NeverFallThroughOrReturn; 2360 } 2361 if (HasAbnormalEdge || HasFakeEdge || HasLiveReturn) 2362 return MaybeFallThrough; 2363 // This says AlwaysFallThrough for calls to functions that are not marked 2364 // noreturn, that don't return. If people would like this warning to be more 2365 // accurate, such functions should be marked as noreturn. 2366 return AlwaysFallThrough; 2367} 2368 2369/// CheckFallThroughForFunctionDef - Check that we don't fall off the end of a 2370/// function that should return a value. Check that we don't fall off the end 2371/// of a noreturn function. We assume that functions and blocks not marked 2372/// noreturn will return. 2373void Sema::CheckFallThroughForFunctionDef(Decl *D, Stmt *Body, 2374 AnalysisContext &AC) { 2375 // FIXME: Would be nice if we had a better way to control cascading errors, 2376 // but for now, avoid them. The problem is that when Parse sees: 2377 // int foo() { return a; } 2378 // The return is eaten and the Sema code sees just: 2379 // int foo() { } 2380 // which this code would then warn about. 2381 if (getDiagnostics().hasErrorOccurred()) 2382 return; 2383 2384 bool ReturnsVoid = false; 2385 bool HasNoReturn = false; 2386 2387 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D)) { 2388 // For function templates, class templates and member function templates 2389 // we'll do the analysis at instantiation time. 2390 if (FD->isDependentContext()) 2391 return; 2392 2393 ReturnsVoid = FD->getResultType()->isVoidType(); 2394 HasNoReturn = FD->hasAttr<NoReturnAttr>() || 2395 FD->getType()->getAs<FunctionType>()->getNoReturnAttr(); 2396 2397 } else if (ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D)) { 2398 ReturnsVoid = MD->getResultType()->isVoidType(); 2399 HasNoReturn = MD->hasAttr<NoReturnAttr>(); 2400 } 2401 2402 // Short circuit for compilation speed. 2403 if ((Diags.getDiagnosticLevel(diag::warn_maybe_falloff_nonvoid_function) 2404 == Diagnostic::Ignored || ReturnsVoid) 2405 && (Diags.getDiagnosticLevel(diag::warn_noreturn_function_has_return_expr) 2406 == Diagnostic::Ignored || !HasNoReturn) 2407 && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block) 2408 == Diagnostic::Ignored || !ReturnsVoid)) 2409 return; 2410 // FIXME: Function try block 2411 if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) { 2412 switch (CheckFallThrough(AC)) { 2413 case MaybeFallThrough: 2414 if (HasNoReturn) 2415 Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function); 2416 else if (!ReturnsVoid) 2417 Diag(Compound->getRBracLoc(),diag::warn_maybe_falloff_nonvoid_function); 2418 break; 2419 case AlwaysFallThrough: 2420 if (HasNoReturn) 2421 Diag(Compound->getRBracLoc(), diag::warn_falloff_noreturn_function); 2422 else if (!ReturnsVoid) 2423 Diag(Compound->getRBracLoc(), diag::warn_falloff_nonvoid_function); 2424 break; 2425 case NeverFallThroughOrReturn: 2426 if (ReturnsVoid && !HasNoReturn) 2427 Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_function); 2428 break; 2429 case NeverFallThrough: 2430 break; 2431 } 2432 } 2433} 2434 2435/// CheckFallThroughForBlock - Check that we don't fall off the end of a block 2436/// that should return a value. Check that we don't fall off the end of a 2437/// noreturn block. We assume that functions and blocks not marked noreturn 2438/// will return. 2439void Sema::CheckFallThroughForBlock(QualType BlockTy, Stmt *Body, 2440 AnalysisContext &AC) { 2441 // FIXME: Would be nice if we had a better way to control cascading errors, 2442 // but for now, avoid them. The problem is that when Parse sees: 2443 // int foo() { return a; } 2444 // The return is eaten and the Sema code sees just: 2445 // int foo() { } 2446 // which this code would then warn about. 2447 if (getDiagnostics().hasErrorOccurred()) 2448 return; 2449 bool ReturnsVoid = false; 2450 bool HasNoReturn = false; 2451 if (const FunctionType *FT =BlockTy->getPointeeType()->getAs<FunctionType>()){ 2452 if (FT->getResultType()->isVoidType()) 2453 ReturnsVoid = true; 2454 if (FT->getNoReturnAttr()) 2455 HasNoReturn = true; 2456 } 2457 2458 // Short circuit for compilation speed. 2459 if (ReturnsVoid 2460 && !HasNoReturn 2461 && (Diags.getDiagnosticLevel(diag::warn_suggest_noreturn_block) 2462 == Diagnostic::Ignored || !ReturnsVoid)) 2463 return; 2464 // FIXME: Funtion try block 2465 if (CompoundStmt *Compound = dyn_cast<CompoundStmt>(Body)) { 2466 switch (CheckFallThrough(AC)) { 2467 case MaybeFallThrough: 2468 if (HasNoReturn) 2469 Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr); 2470 else if (!ReturnsVoid) 2471 Diag(Compound->getRBracLoc(), diag::err_maybe_falloff_nonvoid_block); 2472 break; 2473 case AlwaysFallThrough: 2474 if (HasNoReturn) 2475 Diag(Compound->getRBracLoc(), diag::err_noreturn_block_has_return_expr); 2476 else if (!ReturnsVoid) 2477 Diag(Compound->getRBracLoc(), diag::err_falloff_nonvoid_block); 2478 break; 2479 case NeverFallThroughOrReturn: 2480 if (ReturnsVoid) 2481 Diag(Compound->getLBracLoc(), diag::warn_suggest_noreturn_block); 2482 break; 2483 case NeverFallThrough: 2484 break; 2485 } 2486 } 2487} 2488 2489/// CheckParmsForFunctionDef - Check that the parameters of the given 2490/// function are appropriate for the definition of a function. This 2491/// takes care of any checks that cannot be performed on the 2492/// declaration itself, e.g., that the types of each of the function 2493/// parameters are complete. 2494bool Sema::CheckParmsForFunctionDef(FunctionDecl *FD) { 2495 bool HasInvalidParm = false; 2496 for (unsigned p = 0, NumParams = FD->getNumParams(); p < NumParams; ++p) { 2497 ParmVarDecl *Param = FD->getParamDecl(p); 2498 2499 // C99 6.7.5.3p4: the parameters in a parameter type list in a 2500 // function declarator that is part of a function definition of 2501 // that function shall not have incomplete type. 2502 // 2503 // This is also C++ [dcl.fct]p6. 2504 if (!Param->isInvalidDecl() && 2505 RequireCompleteType(Param->getLocation(), Param->getType(), 2506 diag::err_typecheck_decl_incomplete_type)) { 2507 Param->setInvalidDecl(); 2508 HasInvalidParm = true; 2509 } 2510 2511 // C99 6.9.1p5: If the declarator includes a parameter type list, the 2512 // declaration of each parameter shall include an identifier. 2513 if (Param->getIdentifier() == 0 && 2514 !Param->isImplicit() && 2515 !getLangOptions().CPlusPlus) 2516 Diag(Param->getLocation(), diag::err_parameter_name_omitted); 2517 2518 // C99 6.7.5.3p12: 2519 // If the function declarator is not part of a definition of that 2520 // function, parameters may have incomplete type and may use the [*] 2521 // notation in their sequences of declarator specifiers to specify 2522 // variable length array types. 2523 QualType PType = Param->getOriginalType(); 2524 if (const ArrayType *AT = Context.getAsArrayType(PType)) { 2525 if (AT->getSizeModifier() == ArrayType::Star) { 2526 // FIXME: This diagnosic should point the the '[*]' if source-location 2527 // information is added for it. 2528 Diag(Param->getLocation(), diag::err_array_star_in_function_definition); 2529 } 2530 } 2531 2532 if (getLangOptions().CPlusPlus) 2533 if (const RecordType *RT = Param->getType()->getAs<RecordType>()) 2534 FinalizeVarWithDestructor(Param, RT); 2535 } 2536 2537 return HasInvalidParm; 2538} 2539