CGStmt.cpp revision c2c90011a688c04a4e980282f08c267e081c4b00
1//===--- CGStmt.cpp - Emit LLVM Code from Statements ----------------------===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This contains code to emit Stmt nodes as LLVM code. 11// 12//===----------------------------------------------------------------------===// 13 14#include "CGDebugInfo.h" 15#include "CodeGenModule.h" 16#include "CodeGenFunction.h" 17#include "TargetInfo.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/Basic/PrettyStackTrace.h" 20#include "clang/Basic/TargetInfo.h" 21#include "llvm/ADT/StringExtras.h" 22#include "llvm/InlineAsm.h" 23#include "llvm/Intrinsics.h" 24#include "llvm/Target/TargetData.h" 25using namespace clang; 26using namespace CodeGen; 27 28//===----------------------------------------------------------------------===// 29// Statement Emission 30//===----------------------------------------------------------------------===// 31 32void CodeGenFunction::EmitStopPoint(const Stmt *S) { 33 if (CGDebugInfo *DI = getDebugInfo()) { 34 if (isa<DeclStmt>(S)) 35 DI->setLocation(S->getLocEnd()); 36 else 37 DI->setLocation(S->getLocStart()); 38 DI->UpdateLineDirectiveRegion(Builder); 39 DI->EmitStopPoint(Builder); 40 } 41} 42 43void CodeGenFunction::EmitStmt(const Stmt *S) { 44 assert(S && "Null statement?"); 45 46 // Check if we can handle this without bothering to generate an 47 // insert point or debug info. 48 if (EmitSimpleStmt(S)) 49 return; 50 51 // Check if we are generating unreachable code. 52 if (!HaveInsertPoint()) { 53 // If so, and the statement doesn't contain a label, then we do not need to 54 // generate actual code. This is safe because (1) the current point is 55 // unreachable, so we don't need to execute the code, and (2) we've already 56 // handled the statements which update internal data structures (like the 57 // local variable map) which could be used by subsequent statements. 58 if (!ContainsLabel(S)) { 59 // Verify that any decl statements were handled as simple, they may be in 60 // scope of subsequent reachable statements. 61 assert(!isa<DeclStmt>(*S) && "Unexpected DeclStmt!"); 62 return; 63 } 64 65 // Otherwise, make a new block to hold the code. 66 EnsureInsertPoint(); 67 } 68 69 // Generate a stoppoint if we are emitting debug info. 70 EmitStopPoint(S); 71 72 switch (S->getStmtClass()) { 73 case Stmt::NoStmtClass: 74 case Stmt::CXXCatchStmtClass: 75 llvm_unreachable("invalid statement class to emit generically"); 76 case Stmt::NullStmtClass: 77 case Stmt::CompoundStmtClass: 78 case Stmt::DeclStmtClass: 79 case Stmt::LabelStmtClass: 80 case Stmt::GotoStmtClass: 81 case Stmt::BreakStmtClass: 82 case Stmt::ContinueStmtClass: 83 case Stmt::DefaultStmtClass: 84 case Stmt::CaseStmtClass: 85 llvm_unreachable("should have emitted these statements as simple"); 86 87#define STMT(Type, Base) 88#define ABSTRACT_STMT(Op) 89#define EXPR(Type, Base) \ 90 case Stmt::Type##Class: 91#include "clang/AST/StmtNodes.inc" 92 { 93 // Remember the block we came in on. 94 llvm::BasicBlock *incoming = Builder.GetInsertBlock(); 95 assert(incoming && "expression emission must have an insertion point"); 96 97 EmitIgnoredExpr(cast<Expr>(S)); 98 99 llvm::BasicBlock *outgoing = Builder.GetInsertBlock(); 100 assert(outgoing && "expression emission cleared block!"); 101 102 // The expression emitters assume (reasonably!) that the insertion 103 // point is always set. To maintain that, the call-emission code 104 // for noreturn functions has to enter a new block with no 105 // predecessors. We want to kill that block and mark the current 106 // insertion point unreachable in the common case of a call like 107 // "exit();". Since expression emission doesn't otherwise create 108 // blocks with no predecessors, we can just test for that. 109 // However, we must be careful not to do this to our incoming 110 // block, because *statement* emission does sometimes create 111 // reachable blocks which will have no predecessors until later in 112 // the function. This occurs with, e.g., labels that are not 113 // reachable by fallthrough. 114 if (incoming != outgoing && outgoing->use_empty()) { 115 outgoing->eraseFromParent(); 116 Builder.ClearInsertionPoint(); 117 } 118 break; 119 } 120 121 case Stmt::IndirectGotoStmtClass: 122 EmitIndirectGotoStmt(cast<IndirectGotoStmt>(*S)); break; 123 124 case Stmt::IfStmtClass: EmitIfStmt(cast<IfStmt>(*S)); break; 125 case Stmt::WhileStmtClass: EmitWhileStmt(cast<WhileStmt>(*S)); break; 126 case Stmt::DoStmtClass: EmitDoStmt(cast<DoStmt>(*S)); break; 127 case Stmt::ForStmtClass: EmitForStmt(cast<ForStmt>(*S)); break; 128 129 case Stmt::ReturnStmtClass: EmitReturnStmt(cast<ReturnStmt>(*S)); break; 130 131 case Stmt::SwitchStmtClass: EmitSwitchStmt(cast<SwitchStmt>(*S)); break; 132 case Stmt::AsmStmtClass: EmitAsmStmt(cast<AsmStmt>(*S)); break; 133 134 case Stmt::ObjCAtTryStmtClass: 135 EmitObjCAtTryStmt(cast<ObjCAtTryStmt>(*S)); 136 break; 137 case Stmt::ObjCAtCatchStmtClass: 138 assert(0 && "@catch statements should be handled by EmitObjCAtTryStmt"); 139 break; 140 case Stmt::ObjCAtFinallyStmtClass: 141 assert(0 && "@finally statements should be handled by EmitObjCAtTryStmt"); 142 break; 143 case Stmt::ObjCAtThrowStmtClass: 144 EmitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(*S)); 145 break; 146 case Stmt::ObjCAtSynchronizedStmtClass: 147 EmitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(*S)); 148 break; 149 case Stmt::ObjCForCollectionStmtClass: 150 EmitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(*S)); 151 break; 152 153 case Stmt::CXXTryStmtClass: 154 EmitCXXTryStmt(cast<CXXTryStmt>(*S)); 155 break; 156 } 157} 158 159bool CodeGenFunction::EmitSimpleStmt(const Stmt *S) { 160 switch (S->getStmtClass()) { 161 default: return false; 162 case Stmt::NullStmtClass: break; 163 case Stmt::CompoundStmtClass: EmitCompoundStmt(cast<CompoundStmt>(*S)); break; 164 case Stmt::DeclStmtClass: EmitDeclStmt(cast<DeclStmt>(*S)); break; 165 case Stmt::LabelStmtClass: EmitLabelStmt(cast<LabelStmt>(*S)); break; 166 case Stmt::GotoStmtClass: EmitGotoStmt(cast<GotoStmt>(*S)); break; 167 case Stmt::BreakStmtClass: EmitBreakStmt(cast<BreakStmt>(*S)); break; 168 case Stmt::ContinueStmtClass: EmitContinueStmt(cast<ContinueStmt>(*S)); break; 169 case Stmt::DefaultStmtClass: EmitDefaultStmt(cast<DefaultStmt>(*S)); break; 170 case Stmt::CaseStmtClass: EmitCaseStmt(cast<CaseStmt>(*S)); break; 171 } 172 173 return true; 174} 175 176/// EmitCompoundStmt - Emit a compound statement {..} node. If GetLast is true, 177/// this captures the expression result of the last sub-statement and returns it 178/// (for use by the statement expression extension). 179RValue CodeGenFunction::EmitCompoundStmt(const CompoundStmt &S, bool GetLast, 180 AggValueSlot AggSlot) { 181 PrettyStackTraceLoc CrashInfo(getContext().getSourceManager(),S.getLBracLoc(), 182 "LLVM IR generation of compound statement ('{}')"); 183 184 CGDebugInfo *DI = getDebugInfo(); 185 if (DI) { 186 DI->setLocation(S.getLBracLoc()); 187 DI->EmitRegionStart(Builder); 188 } 189 190 // Keep track of the current cleanup stack depth. 191 RunCleanupsScope Scope(*this); 192 193 for (CompoundStmt::const_body_iterator I = S.body_begin(), 194 E = S.body_end()-GetLast; I != E; ++I) 195 EmitStmt(*I); 196 197 if (DI) { 198 DI->setLocation(S.getRBracLoc()); 199 DI->EmitRegionEnd(Builder); 200 } 201 202 RValue RV; 203 if (!GetLast) 204 RV = RValue::get(0); 205 else { 206 // We have to special case labels here. They are statements, but when put 207 // at the end of a statement expression, they yield the value of their 208 // subexpression. Handle this by walking through all labels we encounter, 209 // emitting them before we evaluate the subexpr. 210 const Stmt *LastStmt = S.body_back(); 211 while (const LabelStmt *LS = dyn_cast<LabelStmt>(LastStmt)) { 212 EmitLabel(LS->getDecl()); 213 LastStmt = LS->getSubStmt(); 214 } 215 216 EnsureInsertPoint(); 217 218 RV = EmitAnyExpr(cast<Expr>(LastStmt), AggSlot); 219 } 220 221 return RV; 222} 223 224void CodeGenFunction::SimplifyForwardingBlocks(llvm::BasicBlock *BB) { 225 llvm::BranchInst *BI = dyn_cast<llvm::BranchInst>(BB->getTerminator()); 226 227 // If there is a cleanup stack, then we it isn't worth trying to 228 // simplify this block (we would need to remove it from the scope map 229 // and cleanup entry). 230 if (!EHStack.empty()) 231 return; 232 233 // Can only simplify direct branches. 234 if (!BI || !BI->isUnconditional()) 235 return; 236 237 BB->replaceAllUsesWith(BI->getSuccessor(0)); 238 BI->eraseFromParent(); 239 BB->eraseFromParent(); 240} 241 242void CodeGenFunction::EmitBlock(llvm::BasicBlock *BB, bool IsFinished) { 243 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 244 245 // Fall out of the current block (if necessary). 246 EmitBranch(BB); 247 248 if (IsFinished && BB->use_empty()) { 249 delete BB; 250 return; 251 } 252 253 // Place the block after the current block, if possible, or else at 254 // the end of the function. 255 if (CurBB && CurBB->getParent()) 256 CurFn->getBasicBlockList().insertAfter(CurBB, BB); 257 else 258 CurFn->getBasicBlockList().push_back(BB); 259 Builder.SetInsertPoint(BB); 260} 261 262void CodeGenFunction::EmitBranch(llvm::BasicBlock *Target) { 263 // Emit a branch from the current block to the target one if this 264 // was a real block. If this was just a fall-through block after a 265 // terminator, don't emit it. 266 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 267 268 if (!CurBB || CurBB->getTerminator()) { 269 // If there is no insert point or the previous block is already 270 // terminated, don't touch it. 271 } else { 272 // Otherwise, create a fall-through branch. 273 Builder.CreateBr(Target); 274 } 275 276 Builder.ClearInsertionPoint(); 277} 278 279CodeGenFunction::JumpDest 280CodeGenFunction::getJumpDestForLabel(const LabelDecl *D) { 281 JumpDest &Dest = LabelMap[D]; 282 if (Dest.isValid()) return Dest; 283 284 // Create, but don't insert, the new block. 285 Dest = JumpDest(createBasicBlock(D->getName()), 286 EHScopeStack::stable_iterator::invalid(), 287 NextCleanupDestIndex++); 288 return Dest; 289} 290 291void CodeGenFunction::EmitLabel(const LabelDecl *D) { 292 JumpDest &Dest = LabelMap[D]; 293 294 // If we didn't need a forward reference to this label, just go 295 // ahead and create a destination at the current scope. 296 if (!Dest.isValid()) { 297 Dest = getJumpDestInCurrentScope(D->getName()); 298 299 // Otherwise, we need to give this label a target depth and remove 300 // it from the branch-fixups list. 301 } else { 302 assert(!Dest.getScopeDepth().isValid() && "already emitted label!"); 303 Dest = JumpDest(Dest.getBlock(), 304 EHStack.stable_begin(), 305 Dest.getDestIndex()); 306 307 ResolveBranchFixups(Dest.getBlock()); 308 } 309 310 EmitBlock(Dest.getBlock()); 311} 312 313 314void CodeGenFunction::EmitLabelStmt(const LabelStmt &S) { 315 EmitLabel(S.getDecl()); 316 EmitStmt(S.getSubStmt()); 317} 318 319void CodeGenFunction::EmitGotoStmt(const GotoStmt &S) { 320 // If this code is reachable then emit a stop point (if generating 321 // debug info). We have to do this ourselves because we are on the 322 // "simple" statement path. 323 if (HaveInsertPoint()) 324 EmitStopPoint(&S); 325 326 EmitBranchThroughCleanup(getJumpDestForLabel(S.getLabel())); 327} 328 329 330void CodeGenFunction::EmitIndirectGotoStmt(const IndirectGotoStmt &S) { 331 if (const LabelDecl *Target = S.getConstantTarget()) { 332 EmitBranchThroughCleanup(getJumpDestForLabel(Target)); 333 return; 334 } 335 336 // Ensure that we have an i8* for our PHI node. 337 llvm::Value *V = Builder.CreateBitCast(EmitScalarExpr(S.getTarget()), 338 Int8PtrTy, "addr"); 339 llvm::BasicBlock *CurBB = Builder.GetInsertBlock(); 340 341 342 // Get the basic block for the indirect goto. 343 llvm::BasicBlock *IndGotoBB = GetIndirectGotoBlock(); 344 345 // The first instruction in the block has to be the PHI for the switch dest, 346 // add an entry for this branch. 347 cast<llvm::PHINode>(IndGotoBB->begin())->addIncoming(V, CurBB); 348 349 EmitBranch(IndGotoBB); 350} 351 352void CodeGenFunction::EmitIfStmt(const IfStmt &S) { 353 // C99 6.8.4.1: The first substatement is executed if the expression compares 354 // unequal to 0. The condition must be a scalar type. 355 RunCleanupsScope ConditionScope(*this); 356 357 if (S.getConditionVariable()) 358 EmitAutoVarDecl(*S.getConditionVariable()); 359 360 // If the condition constant folds and can be elided, try to avoid emitting 361 // the condition and the dead arm of the if/else. 362 bool CondConstant; 363 if (ConstantFoldsToSimpleInteger(S.getCond(), CondConstant)) { 364 // Figure out which block (then or else) is executed. 365 const Stmt *Executed = S.getThen(); 366 const Stmt *Skipped = S.getElse(); 367 if (!CondConstant) // Condition false? 368 std::swap(Executed, Skipped); 369 370 // If the skipped block has no labels in it, just emit the executed block. 371 // This avoids emitting dead code and simplifies the CFG substantially. 372 if (!ContainsLabel(Skipped)) { 373 if (Executed) { 374 RunCleanupsScope ExecutedScope(*this); 375 EmitStmt(Executed); 376 } 377 return; 378 } 379 } 380 381 // Otherwise, the condition did not fold, or we couldn't elide it. Just emit 382 // the conditional branch. 383 llvm::BasicBlock *ThenBlock = createBasicBlock("if.then"); 384 llvm::BasicBlock *ContBlock = createBasicBlock("if.end"); 385 llvm::BasicBlock *ElseBlock = ContBlock; 386 if (S.getElse()) 387 ElseBlock = createBasicBlock("if.else"); 388 EmitBranchOnBoolExpr(S.getCond(), ThenBlock, ElseBlock); 389 390 // Emit the 'then' code. 391 EmitBlock(ThenBlock); 392 { 393 RunCleanupsScope ThenScope(*this); 394 EmitStmt(S.getThen()); 395 } 396 EmitBranch(ContBlock); 397 398 // Emit the 'else' code if present. 399 if (const Stmt *Else = S.getElse()) { 400 EmitBlock(ElseBlock); 401 { 402 RunCleanupsScope ElseScope(*this); 403 EmitStmt(Else); 404 } 405 EmitBranch(ContBlock); 406 } 407 408 // Emit the continuation block for code after the if. 409 EmitBlock(ContBlock, true); 410} 411 412void CodeGenFunction::EmitWhileStmt(const WhileStmt &S) { 413 // Emit the header for the loop, which will also become 414 // the continue target. 415 JumpDest LoopHeader = getJumpDestInCurrentScope("while.cond"); 416 EmitBlock(LoopHeader.getBlock()); 417 418 // Create an exit block for when the condition fails, which will 419 // also become the break target. 420 JumpDest LoopExit = getJumpDestInCurrentScope("while.end"); 421 422 // Store the blocks to use for break and continue. 423 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopHeader)); 424 425 // C++ [stmt.while]p2: 426 // When the condition of a while statement is a declaration, the 427 // scope of the variable that is declared extends from its point 428 // of declaration (3.3.2) to the end of the while statement. 429 // [...] 430 // The object created in a condition is destroyed and created 431 // with each iteration of the loop. 432 RunCleanupsScope ConditionScope(*this); 433 434 if (S.getConditionVariable()) 435 EmitAutoVarDecl(*S.getConditionVariable()); 436 437 // Evaluate the conditional in the while header. C99 6.8.5.1: The 438 // evaluation of the controlling expression takes place before each 439 // execution of the loop body. 440 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); 441 442 // while(1) is common, avoid extra exit blocks. Be sure 443 // to correctly handle break/continue though. 444 bool EmitBoolCondBranch = true; 445 if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) 446 if (C->isOne()) 447 EmitBoolCondBranch = false; 448 449 // As long as the condition is true, go to the loop body. 450 llvm::BasicBlock *LoopBody = createBasicBlock("while.body"); 451 if (EmitBoolCondBranch) { 452 llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); 453 if (ConditionScope.requiresCleanups()) 454 ExitBlock = createBasicBlock("while.exit"); 455 456 Builder.CreateCondBr(BoolCondVal, LoopBody, ExitBlock); 457 458 if (ExitBlock != LoopExit.getBlock()) { 459 EmitBlock(ExitBlock); 460 EmitBranchThroughCleanup(LoopExit); 461 } 462 } 463 464 // Emit the loop body. We have to emit this in a cleanup scope 465 // because it might be a singleton DeclStmt. 466 { 467 RunCleanupsScope BodyScope(*this); 468 EmitBlock(LoopBody); 469 EmitStmt(S.getBody()); 470 } 471 472 BreakContinueStack.pop_back(); 473 474 // Immediately force cleanup. 475 ConditionScope.ForceCleanup(); 476 477 // Branch to the loop header again. 478 EmitBranch(LoopHeader.getBlock()); 479 480 // Emit the exit block. 481 EmitBlock(LoopExit.getBlock(), true); 482 483 // The LoopHeader typically is just a branch if we skipped emitting 484 // a branch, try to erase it. 485 if (!EmitBoolCondBranch) 486 SimplifyForwardingBlocks(LoopHeader.getBlock()); 487} 488 489void CodeGenFunction::EmitDoStmt(const DoStmt &S) { 490 JumpDest LoopExit = getJumpDestInCurrentScope("do.end"); 491 JumpDest LoopCond = getJumpDestInCurrentScope("do.cond"); 492 493 // Store the blocks to use for break and continue. 494 BreakContinueStack.push_back(BreakContinue(LoopExit, LoopCond)); 495 496 // Emit the body of the loop. 497 llvm::BasicBlock *LoopBody = createBasicBlock("do.body"); 498 EmitBlock(LoopBody); 499 { 500 RunCleanupsScope BodyScope(*this); 501 EmitStmt(S.getBody()); 502 } 503 504 BreakContinueStack.pop_back(); 505 506 EmitBlock(LoopCond.getBlock()); 507 508 // C99 6.8.5.2: "The evaluation of the controlling expression takes place 509 // after each execution of the loop body." 510 511 // Evaluate the conditional in the while header. 512 // C99 6.8.5p2/p4: The first substatement is executed if the expression 513 // compares unequal to 0. The condition must be a scalar type. 514 llvm::Value *BoolCondVal = EvaluateExprAsBool(S.getCond()); 515 516 // "do {} while (0)" is common in macros, avoid extra blocks. Be sure 517 // to correctly handle break/continue though. 518 bool EmitBoolCondBranch = true; 519 if (llvm::ConstantInt *C = dyn_cast<llvm::ConstantInt>(BoolCondVal)) 520 if (C->isZero()) 521 EmitBoolCondBranch = false; 522 523 // As long as the condition is true, iterate the loop. 524 if (EmitBoolCondBranch) 525 Builder.CreateCondBr(BoolCondVal, LoopBody, LoopExit.getBlock()); 526 527 // Emit the exit block. 528 EmitBlock(LoopExit.getBlock()); 529 530 // The DoCond block typically is just a branch if we skipped 531 // emitting a branch, try to erase it. 532 if (!EmitBoolCondBranch) 533 SimplifyForwardingBlocks(LoopCond.getBlock()); 534} 535 536void CodeGenFunction::EmitForStmt(const ForStmt &S) { 537 JumpDest LoopExit = getJumpDestInCurrentScope("for.end"); 538 539 RunCleanupsScope ForScope(*this); 540 541 CGDebugInfo *DI = getDebugInfo(); 542 if (DI) { 543 DI->setLocation(S.getSourceRange().getBegin()); 544 DI->EmitRegionStart(Builder); 545 } 546 547 // Evaluate the first part before the loop. 548 if (S.getInit()) 549 EmitStmt(S.getInit()); 550 551 // Start the loop with a block that tests the condition. 552 // If there's an increment, the continue scope will be overwritten 553 // later. 554 JumpDest Continue = getJumpDestInCurrentScope("for.cond"); 555 llvm::BasicBlock *CondBlock = Continue.getBlock(); 556 EmitBlock(CondBlock); 557 558 // Create a cleanup scope for the condition variable cleanups. 559 RunCleanupsScope ConditionScope(*this); 560 561 llvm::Value *BoolCondVal = 0; 562 if (S.getCond()) { 563 // If the for statement has a condition scope, emit the local variable 564 // declaration. 565 llvm::BasicBlock *ExitBlock = LoopExit.getBlock(); 566 if (S.getConditionVariable()) { 567 EmitAutoVarDecl(*S.getConditionVariable()); 568 } 569 570 // If there are any cleanups between here and the loop-exit scope, 571 // create a block to stage a loop exit along. 572 if (ForScope.requiresCleanups()) 573 ExitBlock = createBasicBlock("for.cond.cleanup"); 574 575 // As long as the condition is true, iterate the loop. 576 llvm::BasicBlock *ForBody = createBasicBlock("for.body"); 577 578 // C99 6.8.5p2/p4: The first substatement is executed if the expression 579 // compares unequal to 0. The condition must be a scalar type. 580 BoolCondVal = EvaluateExprAsBool(S.getCond()); 581 Builder.CreateCondBr(BoolCondVal, ForBody, ExitBlock); 582 583 if (ExitBlock != LoopExit.getBlock()) { 584 EmitBlock(ExitBlock); 585 EmitBranchThroughCleanup(LoopExit); 586 } 587 588 EmitBlock(ForBody); 589 } else { 590 // Treat it as a non-zero constant. Don't even create a new block for the 591 // body, just fall into it. 592 } 593 594 // If the for loop doesn't have an increment we can just use the 595 // condition as the continue block. Otherwise we'll need to create 596 // a block for it (in the current scope, i.e. in the scope of the 597 // condition), and that we will become our continue block. 598 if (S.getInc()) 599 Continue = getJumpDestInCurrentScope("for.inc"); 600 601 // Store the blocks to use for break and continue. 602 BreakContinueStack.push_back(BreakContinue(LoopExit, Continue)); 603 604 { 605 // Create a separate cleanup scope for the body, in case it is not 606 // a compound statement. 607 RunCleanupsScope BodyScope(*this); 608 EmitStmt(S.getBody()); 609 } 610 611 // If there is an increment, emit it next. 612 if (S.getInc()) { 613 EmitBlock(Continue.getBlock()); 614 EmitStmt(S.getInc()); 615 } 616 617 BreakContinueStack.pop_back(); 618 619 ConditionScope.ForceCleanup(); 620 EmitBranch(CondBlock); 621 622 ForScope.ForceCleanup(); 623 624 if (DI) { 625 DI->setLocation(S.getSourceRange().getEnd()); 626 DI->EmitRegionEnd(Builder); 627 } 628 629 // Emit the fall-through block. 630 EmitBlock(LoopExit.getBlock(), true); 631} 632 633void CodeGenFunction::EmitReturnOfRValue(RValue RV, QualType Ty) { 634 if (RV.isScalar()) { 635 Builder.CreateStore(RV.getScalarVal(), ReturnValue); 636 } else if (RV.isAggregate()) { 637 EmitAggregateCopy(ReturnValue, RV.getAggregateAddr(), Ty); 638 } else { 639 StoreComplexToAddr(RV.getComplexVal(), ReturnValue, false); 640 } 641 EmitBranchThroughCleanup(ReturnBlock); 642} 643 644/// EmitReturnStmt - Note that due to GCC extensions, this can have an operand 645/// if the function returns void, or may be missing one if the function returns 646/// non-void. Fun stuff :). 647void CodeGenFunction::EmitReturnStmt(const ReturnStmt &S) { 648 // Emit the result value, even if unused, to evalute the side effects. 649 const Expr *RV = S.getRetValue(); 650 651 // FIXME: Clean this up by using an LValue for ReturnTemp, 652 // EmitStoreThroughLValue, and EmitAnyExpr. 653 if (S.getNRVOCandidate() && S.getNRVOCandidate()->isNRVOVariable() && 654 !Target.useGlobalsForAutomaticVariables()) { 655 // Apply the named return value optimization for this return statement, 656 // which means doing nothing: the appropriate result has already been 657 // constructed into the NRVO variable. 658 659 // If there is an NRVO flag for this variable, set it to 1 into indicate 660 // that the cleanup code should not destroy the variable. 661 if (llvm::Value *NRVOFlag = NRVOFlags[S.getNRVOCandidate()]) 662 Builder.CreateStore(Builder.getTrue(), NRVOFlag); 663 } else if (!ReturnValue) { 664 // Make sure not to return anything, but evaluate the expression 665 // for side effects. 666 if (RV) 667 EmitAnyExpr(RV); 668 } else if (RV == 0) { 669 // Do nothing (return value is left uninitialized) 670 } else if (FnRetTy->isReferenceType()) { 671 // If this function returns a reference, take the address of the expression 672 // rather than the value. 673 RValue Result = EmitReferenceBindingToExpr(RV, /*InitializedDecl=*/0); 674 Builder.CreateStore(Result.getScalarVal(), ReturnValue); 675 } else if (!hasAggregateLLVMType(RV->getType())) { 676 Builder.CreateStore(EmitScalarExpr(RV), ReturnValue); 677 } else if (RV->getType()->isAnyComplexType()) { 678 EmitComplexExprIntoAddr(RV, ReturnValue, false); 679 } else { 680 EmitAggExpr(RV, AggValueSlot::forAddr(ReturnValue, false, true)); 681 } 682 683 EmitBranchThroughCleanup(ReturnBlock); 684} 685 686void CodeGenFunction::EmitDeclStmt(const DeclStmt &S) { 687 // As long as debug info is modeled with instructions, we have to ensure we 688 // have a place to insert here and write the stop point here. 689 if (getDebugInfo()) { 690 EnsureInsertPoint(); 691 EmitStopPoint(&S); 692 } 693 694 for (DeclStmt::const_decl_iterator I = S.decl_begin(), E = S.decl_end(); 695 I != E; ++I) 696 EmitDecl(**I); 697} 698 699void CodeGenFunction::EmitBreakStmt(const BreakStmt &S) { 700 assert(!BreakContinueStack.empty() && "break stmt not in a loop or switch!"); 701 702 // If this code is reachable then emit a stop point (if generating 703 // debug info). We have to do this ourselves because we are on the 704 // "simple" statement path. 705 if (HaveInsertPoint()) 706 EmitStopPoint(&S); 707 708 JumpDest Block = BreakContinueStack.back().BreakBlock; 709 EmitBranchThroughCleanup(Block); 710} 711 712void CodeGenFunction::EmitContinueStmt(const ContinueStmt &S) { 713 assert(!BreakContinueStack.empty() && "continue stmt not in a loop!"); 714 715 // If this code is reachable then emit a stop point (if generating 716 // debug info). We have to do this ourselves because we are on the 717 // "simple" statement path. 718 if (HaveInsertPoint()) 719 EmitStopPoint(&S); 720 721 JumpDest Block = BreakContinueStack.back().ContinueBlock; 722 EmitBranchThroughCleanup(Block); 723} 724 725/// EmitCaseStmtRange - If case statement range is not too big then 726/// add multiple cases to switch instruction, one for each value within 727/// the range. If range is too big then emit "if" condition check. 728void CodeGenFunction::EmitCaseStmtRange(const CaseStmt &S) { 729 assert(S.getRHS() && "Expected RHS value in CaseStmt"); 730 731 llvm::APSInt LHS = S.getLHS()->EvaluateAsInt(getContext()); 732 llvm::APSInt RHS = S.getRHS()->EvaluateAsInt(getContext()); 733 734 // Emit the code for this case. We do this first to make sure it is 735 // properly chained from our predecessor before generating the 736 // switch machinery to enter this block. 737 EmitBlock(createBasicBlock("sw.bb")); 738 llvm::BasicBlock *CaseDest = Builder.GetInsertBlock(); 739 EmitStmt(S.getSubStmt()); 740 741 // If range is empty, do nothing. 742 if (LHS.isSigned() ? RHS.slt(LHS) : RHS.ult(LHS)) 743 return; 744 745 llvm::APInt Range = RHS - LHS; 746 // FIXME: parameters such as this should not be hardcoded. 747 if (Range.ult(llvm::APInt(Range.getBitWidth(), 64))) { 748 // Range is small enough to add multiple switch instruction cases. 749 for (unsigned i = 0, e = Range.getZExtValue() + 1; i != e; ++i) { 750 SwitchInsn->addCase(llvm::ConstantInt::get(getLLVMContext(), LHS), 751 CaseDest); 752 LHS++; 753 } 754 return; 755 } 756 757 // The range is too big. Emit "if" condition into a new block, 758 // making sure to save and restore the current insertion point. 759 llvm::BasicBlock *RestoreBB = Builder.GetInsertBlock(); 760 761 // Push this test onto the chain of range checks (which terminates 762 // in the default basic block). The switch's default will be changed 763 // to the top of this chain after switch emission is complete. 764 llvm::BasicBlock *FalseDest = CaseRangeBlock; 765 CaseRangeBlock = createBasicBlock("sw.caserange"); 766 767 CurFn->getBasicBlockList().push_back(CaseRangeBlock); 768 Builder.SetInsertPoint(CaseRangeBlock); 769 770 // Emit range check. 771 llvm::Value *Diff = 772 Builder.CreateSub(SwitchInsn->getCondition(), 773 llvm::ConstantInt::get(getLLVMContext(), LHS), "tmp"); 774 llvm::Value *Cond = 775 Builder.CreateICmpULE(Diff, llvm::ConstantInt::get(getLLVMContext(), Range), 776 "inbounds"); 777 Builder.CreateCondBr(Cond, CaseDest, FalseDest); 778 779 // Restore the appropriate insertion point. 780 if (RestoreBB) 781 Builder.SetInsertPoint(RestoreBB); 782 else 783 Builder.ClearInsertionPoint(); 784} 785 786void CodeGenFunction::EmitCaseStmt(const CaseStmt &S) { 787 if (S.getRHS()) { 788 EmitCaseStmtRange(S); 789 return; 790 } 791 792 EmitBlock(createBasicBlock("sw.bb")); 793 llvm::BasicBlock *CaseDest = Builder.GetInsertBlock(); 794 llvm::APSInt CaseVal = S.getLHS()->EvaluateAsInt(getContext()); 795 SwitchInsn->addCase(llvm::ConstantInt::get(getLLVMContext(), CaseVal), 796 CaseDest); 797 798 // Recursively emitting the statement is acceptable, but is not wonderful for 799 // code where we have many case statements nested together, i.e.: 800 // case 1: 801 // case 2: 802 // case 3: etc. 803 // Handling this recursively will create a new block for each case statement 804 // that falls through to the next case which is IR intensive. It also causes 805 // deep recursion which can run into stack depth limitations. Handle 806 // sequential non-range case statements specially. 807 const CaseStmt *CurCase = &S; 808 const CaseStmt *NextCase = dyn_cast<CaseStmt>(S.getSubStmt()); 809 810 // Otherwise, iteratively add consequtive cases to this switch stmt. 811 while (NextCase && NextCase->getRHS() == 0) { 812 CurCase = NextCase; 813 CaseVal = CurCase->getLHS()->EvaluateAsInt(getContext()); 814 SwitchInsn->addCase(llvm::ConstantInt::get(getLLVMContext(), CaseVal), 815 CaseDest); 816 817 NextCase = dyn_cast<CaseStmt>(CurCase->getSubStmt()); 818 } 819 820 // Normal default recursion for non-cases. 821 EmitStmt(CurCase->getSubStmt()); 822} 823 824void CodeGenFunction::EmitDefaultStmt(const DefaultStmt &S) { 825 llvm::BasicBlock *DefaultBlock = SwitchInsn->getDefaultDest(); 826 assert(DefaultBlock->empty() && 827 "EmitDefaultStmt: Default block already defined?"); 828 EmitBlock(DefaultBlock); 829 EmitStmt(S.getSubStmt()); 830} 831 832void CodeGenFunction::EmitSwitchStmt(const SwitchStmt &S) { 833 JumpDest SwitchExit = getJumpDestInCurrentScope("sw.epilog"); 834 835 RunCleanupsScope ConditionScope(*this); 836 837 if (S.getConditionVariable()) 838 EmitAutoVarDecl(*S.getConditionVariable()); 839 840 llvm::Value *CondV = EmitScalarExpr(S.getCond()); 841 842 // Handle nested switch statements. 843 llvm::SwitchInst *SavedSwitchInsn = SwitchInsn; 844 llvm::BasicBlock *SavedCRBlock = CaseRangeBlock; 845 846 // Create basic block to hold stuff that comes after switch 847 // statement. We also need to create a default block now so that 848 // explicit case ranges tests can have a place to jump to on 849 // failure. 850 llvm::BasicBlock *DefaultBlock = createBasicBlock("sw.default"); 851 SwitchInsn = Builder.CreateSwitch(CondV, DefaultBlock); 852 CaseRangeBlock = DefaultBlock; 853 854 // Clear the insertion point to indicate we are in unreachable code. 855 Builder.ClearInsertionPoint(); 856 857 // All break statements jump to NextBlock. If BreakContinueStack is non empty 858 // then reuse last ContinueBlock. 859 JumpDest OuterContinue; 860 if (!BreakContinueStack.empty()) 861 OuterContinue = BreakContinueStack.back().ContinueBlock; 862 863 BreakContinueStack.push_back(BreakContinue(SwitchExit, OuterContinue)); 864 865 // Emit switch body. 866 EmitStmt(S.getBody()); 867 868 BreakContinueStack.pop_back(); 869 870 // Update the default block in case explicit case range tests have 871 // been chained on top. 872 SwitchInsn->setSuccessor(0, CaseRangeBlock); 873 874 // If a default was never emitted: 875 if (!DefaultBlock->getParent()) { 876 // If we have cleanups, emit the default block so that there's a 877 // place to jump through the cleanups from. 878 if (ConditionScope.requiresCleanups()) { 879 EmitBlock(DefaultBlock); 880 881 // Otherwise, just forward the default block to the switch end. 882 } else { 883 DefaultBlock->replaceAllUsesWith(SwitchExit.getBlock()); 884 delete DefaultBlock; 885 } 886 } 887 888 ConditionScope.ForceCleanup(); 889 890 // Emit continuation. 891 EmitBlock(SwitchExit.getBlock(), true); 892 893 SwitchInsn = SavedSwitchInsn; 894 CaseRangeBlock = SavedCRBlock; 895} 896 897static std::string 898SimplifyConstraint(const char *Constraint, const TargetInfo &Target, 899 llvm::SmallVectorImpl<TargetInfo::ConstraintInfo> *OutCons=0) { 900 std::string Result; 901 902 while (*Constraint) { 903 switch (*Constraint) { 904 default: 905 Result += Target.convertConstraint(*Constraint); 906 break; 907 // Ignore these 908 case '*': 909 case '?': 910 case '!': 911 case '=': // Will see this and the following in mult-alt constraints. 912 case '+': 913 break; 914 case ',': 915 Result += "|"; 916 break; 917 case 'g': 918 Result += "imr"; 919 break; 920 case '[': { 921 assert(OutCons && 922 "Must pass output names to constraints with a symbolic name"); 923 unsigned Index; 924 bool result = Target.resolveSymbolicName(Constraint, 925 &(*OutCons)[0], 926 OutCons->size(), Index); 927 assert(result && "Could not resolve symbolic name"); (void)result; 928 Result += llvm::utostr(Index); 929 break; 930 } 931 } 932 933 Constraint++; 934 } 935 936 return Result; 937} 938 939/// AddVariableConstraints - Look at AsmExpr and if it is a variable declared 940/// as using a particular register add that as a constraint that will be used 941/// in this asm stmt. 942static std::string 943AddVariableConstraints(const std::string &Constraint, const Expr &AsmExpr, 944 const TargetInfo &Target, CodeGenModule &CGM, 945 const AsmStmt &Stmt) { 946 const DeclRefExpr *AsmDeclRef = dyn_cast<DeclRefExpr>(&AsmExpr); 947 if (!AsmDeclRef) 948 return Constraint; 949 const ValueDecl &Value = *AsmDeclRef->getDecl(); 950 const VarDecl *Variable = dyn_cast<VarDecl>(&Value); 951 if (!Variable) 952 return Constraint; 953 AsmLabelAttr *Attr = Variable->getAttr<AsmLabelAttr>(); 954 if (!Attr) 955 return Constraint; 956 llvm::StringRef Register = Attr->getLabel(); 957 assert(Target.isValidGCCRegisterName(Register)); 958 // FIXME: We should check which registers are compatible with "r" or "x". 959 if (Constraint != "r" && Constraint != "x") { 960 CGM.ErrorUnsupported(&Stmt, "__asm__"); 961 return Constraint; 962 } 963 return "{" + Register.str() + "}"; 964} 965 966llvm::Value* 967CodeGenFunction::EmitAsmInputLValue(const AsmStmt &S, 968 const TargetInfo::ConstraintInfo &Info, 969 LValue InputValue, QualType InputType, 970 std::string &ConstraintStr) { 971 llvm::Value *Arg; 972 if (Info.allowsRegister() || !Info.allowsMemory()) { 973 if (!CodeGenFunction::hasAggregateLLVMType(InputType)) { 974 Arg = EmitLoadOfLValue(InputValue, InputType).getScalarVal(); 975 } else { 976 const llvm::Type *Ty = ConvertType(InputType); 977 uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty); 978 if (Size <= 64 && llvm::isPowerOf2_64(Size)) { 979 Ty = llvm::IntegerType::get(getLLVMContext(), Size); 980 Ty = llvm::PointerType::getUnqual(Ty); 981 982 Arg = Builder.CreateLoad(Builder.CreateBitCast(InputValue.getAddress(), 983 Ty)); 984 } else { 985 Arg = InputValue.getAddress(); 986 ConstraintStr += '*'; 987 } 988 } 989 } else { 990 Arg = InputValue.getAddress(); 991 ConstraintStr += '*'; 992 } 993 994 return Arg; 995} 996 997llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S, 998 const TargetInfo::ConstraintInfo &Info, 999 const Expr *InputExpr, 1000 std::string &ConstraintStr) { 1001 if (Info.allowsRegister() || !Info.allowsMemory()) 1002 if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType())) 1003 return EmitScalarExpr(InputExpr); 1004 1005 InputExpr = InputExpr->IgnoreParenNoopCasts(getContext()); 1006 LValue Dest = EmitLValue(InputExpr); 1007 return EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), ConstraintStr); 1008} 1009 1010/// getAsmSrcLocInfo - Return the !srcloc metadata node to attach to an inline 1011/// asm call instruction. The !srcloc MDNode contains a list of constant 1012/// integers which are the source locations of the start of each line in the 1013/// asm. 1014static llvm::MDNode *getAsmSrcLocInfo(const StringLiteral *Str, 1015 CodeGenFunction &CGF) { 1016 llvm::SmallVector<llvm::Value *, 8> Locs; 1017 // Add the location of the first line to the MDNode. 1018 Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty, 1019 Str->getLocStart().getRawEncoding())); 1020 llvm::StringRef StrVal = Str->getString(); 1021 if (!StrVal.empty()) { 1022 const SourceManager &SM = CGF.CGM.getContext().getSourceManager(); 1023 const LangOptions &LangOpts = CGF.CGM.getLangOptions(); 1024 1025 // Add the location of the start of each subsequent line of the asm to the 1026 // MDNode. 1027 for (unsigned i = 0, e = StrVal.size()-1; i != e; ++i) { 1028 if (StrVal[i] != '\n') continue; 1029 SourceLocation LineLoc = Str->getLocationOfByte(i+1, SM, LangOpts, 1030 CGF.Target); 1031 Locs.push_back(llvm::ConstantInt::get(CGF.Int32Ty, 1032 LineLoc.getRawEncoding())); 1033 } 1034 } 1035 1036 return llvm::MDNode::get(CGF.getLLVMContext(), Locs.data(), Locs.size()); 1037} 1038 1039void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { 1040 // Analyze the asm string to decompose it into its pieces. We know that Sema 1041 // has already done this, so it is guaranteed to be successful. 1042 llvm::SmallVector<AsmStmt::AsmStringPiece, 4> Pieces; 1043 unsigned DiagOffs; 1044 S.AnalyzeAsmString(Pieces, getContext(), DiagOffs); 1045 1046 // Assemble the pieces into the final asm string. 1047 std::string AsmString; 1048 for (unsigned i = 0, e = Pieces.size(); i != e; ++i) { 1049 if (Pieces[i].isString()) 1050 AsmString += Pieces[i].getString(); 1051 else if (Pieces[i].getModifier() == '\0') 1052 AsmString += '$' + llvm::utostr(Pieces[i].getOperandNo()); 1053 else 1054 AsmString += "${" + llvm::utostr(Pieces[i].getOperandNo()) + ':' + 1055 Pieces[i].getModifier() + '}'; 1056 } 1057 1058 // Get all the output and input constraints together. 1059 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> OutputConstraintInfos; 1060 llvm::SmallVector<TargetInfo::ConstraintInfo, 4> InputConstraintInfos; 1061 1062 for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { 1063 TargetInfo::ConstraintInfo Info(S.getOutputConstraint(i), 1064 S.getOutputName(i)); 1065 bool IsValid = Target.validateOutputConstraint(Info); (void)IsValid; 1066 assert(IsValid && "Failed to parse output constraint"); 1067 OutputConstraintInfos.push_back(Info); 1068 } 1069 1070 for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { 1071 TargetInfo::ConstraintInfo Info(S.getInputConstraint(i), 1072 S.getInputName(i)); 1073 bool IsValid = Target.validateInputConstraint(OutputConstraintInfos.data(), 1074 S.getNumOutputs(), Info); 1075 assert(IsValid && "Failed to parse input constraint"); (void)IsValid; 1076 InputConstraintInfos.push_back(Info); 1077 } 1078 1079 std::string Constraints; 1080 1081 std::vector<LValue> ResultRegDests; 1082 std::vector<QualType> ResultRegQualTys; 1083 std::vector<const llvm::Type *> ResultRegTypes; 1084 std::vector<const llvm::Type *> ResultTruncRegTypes; 1085 std::vector<const llvm::Type*> ArgTypes; 1086 std::vector<llvm::Value*> Args; 1087 1088 // Keep track of inout constraints. 1089 std::string InOutConstraints; 1090 std::vector<llvm::Value*> InOutArgs; 1091 std::vector<const llvm::Type*> InOutArgTypes; 1092 1093 for (unsigned i = 0, e = S.getNumOutputs(); i != e; i++) { 1094 TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i]; 1095 1096 // Simplify the output constraint. 1097 std::string OutputConstraint(S.getOutputConstraint(i)); 1098 OutputConstraint = SimplifyConstraint(OutputConstraint.c_str() + 1, Target); 1099 1100 const Expr *OutExpr = S.getOutputExpr(i); 1101 OutExpr = OutExpr->IgnoreParenNoopCasts(getContext()); 1102 1103 OutputConstraint = AddVariableConstraints(OutputConstraint, *OutExpr, Target, 1104 CGM, S); 1105 1106 LValue Dest = EmitLValue(OutExpr); 1107 if (!Constraints.empty()) 1108 Constraints += ','; 1109 1110 // If this is a register output, then make the inline asm return it 1111 // by-value. If this is a memory result, return the value by-reference. 1112 if (!Info.allowsMemory() && !hasAggregateLLVMType(OutExpr->getType())) { 1113 Constraints += "=" + OutputConstraint; 1114 ResultRegQualTys.push_back(OutExpr->getType()); 1115 ResultRegDests.push_back(Dest); 1116 ResultRegTypes.push_back(ConvertTypeForMem(OutExpr->getType())); 1117 ResultTruncRegTypes.push_back(ResultRegTypes.back()); 1118 1119 // If this output is tied to an input, and if the input is larger, then 1120 // we need to set the actual result type of the inline asm node to be the 1121 // same as the input type. 1122 if (Info.hasMatchingInput()) { 1123 unsigned InputNo; 1124 for (InputNo = 0; InputNo != S.getNumInputs(); ++InputNo) { 1125 TargetInfo::ConstraintInfo &Input = InputConstraintInfos[InputNo]; 1126 if (Input.hasTiedOperand() && Input.getTiedOperand() == i) 1127 break; 1128 } 1129 assert(InputNo != S.getNumInputs() && "Didn't find matching input!"); 1130 1131 QualType InputTy = S.getInputExpr(InputNo)->getType(); 1132 QualType OutputType = OutExpr->getType(); 1133 1134 uint64_t InputSize = getContext().getTypeSize(InputTy); 1135 if (getContext().getTypeSize(OutputType) < InputSize) { 1136 // Form the asm to return the value as a larger integer or fp type. 1137 ResultRegTypes.back() = ConvertType(InputTy); 1138 } 1139 } 1140 if (const llvm::Type* AdjTy = 1141 getTargetHooks().adjustInlineAsmType(*this, OutputConstraint, 1142 ResultRegTypes.back())) 1143 ResultRegTypes.back() = AdjTy; 1144 } else { 1145 ArgTypes.push_back(Dest.getAddress()->getType()); 1146 Args.push_back(Dest.getAddress()); 1147 Constraints += "=*"; 1148 Constraints += OutputConstraint; 1149 } 1150 1151 if (Info.isReadWrite()) { 1152 InOutConstraints += ','; 1153 1154 const Expr *InputExpr = S.getOutputExpr(i); 1155 llvm::Value *Arg = EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), 1156 InOutConstraints); 1157 1158 if (Info.allowsRegister()) 1159 InOutConstraints += llvm::utostr(i); 1160 else 1161 InOutConstraints += OutputConstraint; 1162 1163 InOutArgTypes.push_back(Arg->getType()); 1164 InOutArgs.push_back(Arg); 1165 } 1166 } 1167 1168 unsigned NumConstraints = S.getNumOutputs() + S.getNumInputs(); 1169 1170 for (unsigned i = 0, e = S.getNumInputs(); i != e; i++) { 1171 const Expr *InputExpr = S.getInputExpr(i); 1172 1173 TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i]; 1174 1175 if (!Constraints.empty()) 1176 Constraints += ','; 1177 1178 // Simplify the input constraint. 1179 std::string InputConstraint(S.getInputConstraint(i)); 1180 InputConstraint = SimplifyConstraint(InputConstraint.c_str(), Target, 1181 &OutputConstraintInfos); 1182 1183 InputConstraint = 1184 AddVariableConstraints(InputConstraint, 1185 *InputExpr->IgnoreParenNoopCasts(getContext()), 1186 Target, CGM, S); 1187 1188 llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, Constraints); 1189 1190 // If this input argument is tied to a larger output result, extend the 1191 // input to be the same size as the output. The LLVM backend wants to see 1192 // the input and output of a matching constraint be the same size. Note 1193 // that GCC does not define what the top bits are here. We use zext because 1194 // that is usually cheaper, but LLVM IR should really get an anyext someday. 1195 if (Info.hasTiedOperand()) { 1196 unsigned Output = Info.getTiedOperand(); 1197 QualType OutputType = S.getOutputExpr(Output)->getType(); 1198 QualType InputTy = InputExpr->getType(); 1199 1200 if (getContext().getTypeSize(OutputType) > 1201 getContext().getTypeSize(InputTy)) { 1202 // Use ptrtoint as appropriate so that we can do our extension. 1203 if (isa<llvm::PointerType>(Arg->getType())) 1204 Arg = Builder.CreatePtrToInt(Arg, IntPtrTy); 1205 const llvm::Type *OutputTy = ConvertType(OutputType); 1206 if (isa<llvm::IntegerType>(OutputTy)) 1207 Arg = Builder.CreateZExt(Arg, OutputTy); 1208 else 1209 Arg = Builder.CreateFPExt(Arg, OutputTy); 1210 } 1211 } 1212 if (const llvm::Type* AdjTy = 1213 getTargetHooks().adjustInlineAsmType(*this, InputConstraint, 1214 Arg->getType())) 1215 Arg = Builder.CreateBitCast(Arg, AdjTy); 1216 1217 ArgTypes.push_back(Arg->getType()); 1218 Args.push_back(Arg); 1219 Constraints += InputConstraint; 1220 } 1221 1222 // Append the "input" part of inout constraints last. 1223 for (unsigned i = 0, e = InOutArgs.size(); i != e; i++) { 1224 ArgTypes.push_back(InOutArgTypes[i]); 1225 Args.push_back(InOutArgs[i]); 1226 } 1227 Constraints += InOutConstraints; 1228 1229 // Clobbers 1230 for (unsigned i = 0, e = S.getNumClobbers(); i != e; i++) { 1231 llvm::StringRef Clobber = S.getClobber(i)->getString(); 1232 1233 Clobber = Target.getNormalizedGCCRegisterName(Clobber); 1234 1235 if (i != 0 || NumConstraints != 0) 1236 Constraints += ','; 1237 1238 Constraints += "~{"; 1239 Constraints += Clobber; 1240 Constraints += '}'; 1241 } 1242 1243 // Add machine specific clobbers 1244 std::string MachineClobbers = Target.getClobbers(); 1245 if (!MachineClobbers.empty()) { 1246 if (!Constraints.empty()) 1247 Constraints += ','; 1248 Constraints += MachineClobbers; 1249 } 1250 1251 const llvm::Type *ResultType; 1252 if (ResultRegTypes.empty()) 1253 ResultType = llvm::Type::getVoidTy(getLLVMContext()); 1254 else if (ResultRegTypes.size() == 1) 1255 ResultType = ResultRegTypes[0]; 1256 else 1257 ResultType = llvm::StructType::get(getLLVMContext(), ResultRegTypes); 1258 1259 const llvm::FunctionType *FTy = 1260 llvm::FunctionType::get(ResultType, ArgTypes, false); 1261 1262 llvm::InlineAsm *IA = 1263 llvm::InlineAsm::get(FTy, AsmString, Constraints, 1264 S.isVolatile() || S.getNumOutputs() == 0); 1265 llvm::CallInst *Result = Builder.CreateCall(IA, Args.begin(), Args.end()); 1266 Result->addAttribute(~0, llvm::Attribute::NoUnwind); 1267 1268 // Slap the source location of the inline asm into a !srcloc metadata on the 1269 // call. 1270 Result->setMetadata("srcloc", getAsmSrcLocInfo(S.getAsmString(), *this)); 1271 1272 // Extract all of the register value results from the asm. 1273 std::vector<llvm::Value*> RegResults; 1274 if (ResultRegTypes.size() == 1) { 1275 RegResults.push_back(Result); 1276 } else { 1277 for (unsigned i = 0, e = ResultRegTypes.size(); i != e; ++i) { 1278 llvm::Value *Tmp = Builder.CreateExtractValue(Result, i, "asmresult"); 1279 RegResults.push_back(Tmp); 1280 } 1281 } 1282 1283 for (unsigned i = 0, e = RegResults.size(); i != e; ++i) { 1284 llvm::Value *Tmp = RegResults[i]; 1285 1286 // If the result type of the LLVM IR asm doesn't match the result type of 1287 // the expression, do the conversion. 1288 if (ResultRegTypes[i] != ResultTruncRegTypes[i]) { 1289 const llvm::Type *TruncTy = ResultTruncRegTypes[i]; 1290 1291 // Truncate the integer result to the right size, note that TruncTy can be 1292 // a pointer. 1293 if (TruncTy->isFloatingPointTy()) 1294 Tmp = Builder.CreateFPTrunc(Tmp, TruncTy); 1295 else if (TruncTy->isPointerTy() && Tmp->getType()->isIntegerTy()) { 1296 uint64_t ResSize = CGM.getTargetData().getTypeSizeInBits(TruncTy); 1297 Tmp = Builder.CreateTrunc(Tmp, 1298 llvm::IntegerType::get(getLLVMContext(), (unsigned)ResSize)); 1299 Tmp = Builder.CreateIntToPtr(Tmp, TruncTy); 1300 } else if (Tmp->getType()->isPointerTy() && TruncTy->isIntegerTy()) { 1301 uint64_t TmpSize =CGM.getTargetData().getTypeSizeInBits(Tmp->getType()); 1302 Tmp = Builder.CreatePtrToInt(Tmp, 1303 llvm::IntegerType::get(getLLVMContext(), (unsigned)TmpSize)); 1304 Tmp = Builder.CreateTrunc(Tmp, TruncTy); 1305 } else if (TruncTy->isIntegerTy()) { 1306 Tmp = Builder.CreateTrunc(Tmp, TruncTy); 1307 } else if (TruncTy->isVectorTy()) { 1308 Tmp = Builder.CreateBitCast(Tmp, TruncTy); 1309 } 1310 } 1311 1312 EmitStoreThroughLValue(RValue::get(Tmp), ResultRegDests[i], 1313 ResultRegQualTys[i]); 1314 } 1315} 1316