IntrinsicLowering.cpp revision 2751e76a709738590242adce47a3b55bc77fd36d 
1//===-- IntrinsicLowering.cpp - Intrinsic Lowering default implementation -===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file was developed by the LLVM research group and is distributed under
6// the University of Illinois Open Source License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file implements the default intrinsic lowering implementation.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/IntrinsicLowering.h"
15#include "llvm/Constant.h"
16#include "llvm/DerivedTypes.h"
17#include "llvm/Module.h"
18#include "llvm/iOther.h"
19using namespace llvm;
20
21void DefaultIntrinsicLowering::LowerIntrinsicCall(CallInst *CI) {
22  Function *Callee = CI->getCalledFunction();
23  assert(Callee && "Cannot lower an indirect call!");
24
25  Module *M = Callee->getParent();
26
27  switch (Callee->getIntrinsicID()) {
28  case Intrinsic::not_intrinsic:
29    std::cerr << "Cannot lower a call to a non-intrinsic function '"
30              << Callee->getName() << "'!\n";
31    abort();
32  default:
33    std::cerr << "Error: Code generator does not support intrinsic function '"
34              << Callee->getName() << "'!\n";
35    abort();
36
37    // The default implementation of setjmp/longjmp transforms setjmp into a
38    // noop that always returns zero and longjmp into a call to abort.  This
39    // allows code that never longjmps to work correctly.
40  case Intrinsic::setjmp:
41  case Intrinsic::sigsetjmp:
42    if (CI->getType() != Type::VoidTy)
43      CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
44    break;
45
46  case Intrinsic::longjmp:
47  case Intrinsic::siglongjmp:
48    // Insert the call to abort
49    new CallInst(M->getOrInsertFunction("abort", Type::VoidTy, 0), "", CI);
50    break;
51
52  case Intrinsic::dbg_stoppoint:
53  case Intrinsic::dbg_region_start:
54  case Intrinsic::dbg_region_end:
55  case Intrinsic::dbg_declare:
56  case Intrinsic::dbg_func_start:
57    if (CI->getType() != Type::VoidTy)
58      CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
59    break;    // Simply strip out debugging intrinsics
60
61  case Intrinsic::memcpy: {
62    // The memcpy intrinsic take an extra alignment argument that the memcpy
63    // libc function does not.
64    const FunctionType *CFT = Callee->getFunctionType();
65    FunctionType *FT =
66      FunctionType::get(*CFT->param_begin(),
67           std::vector<const Type*>(CFT->param_begin(), CFT->param_end()-1),
68                        false);
69    Function *MemCpy = M->getOrInsertFunction("memcpy", FT);
70    new CallInst(MemCpy, std::vector<Value*>(CI->op_begin()+1, CI->op_end()-1),
71                 CI->getName(), CI);
72    break;
73  }
74  case Intrinsic::memmove: {
75    // The memmove intrinsic take an extra alignment argument that the memcpy
76    // libc function does not.
77    const FunctionType *CFT = Callee->getFunctionType();
78    FunctionType *FT =
79      FunctionType::get(*CFT->param_begin(),
80           std::vector<const Type*>(CFT->param_begin(), CFT->param_end()-1),
81                        false);
82    Function *MemMove = M->getOrInsertFunction("memmove", FT);
83    new CallInst(MemMove, std::vector<Value*>(CI->op_begin()+1, CI->op_end()-1),
84                 CI->getName(), CI);
85    break;
86  }
87  }
88
89  assert(CI->use_empty() &&
90         "Lowering should have eliminated any uses of the intrinsic call!");
91  CI->getParent()->getInstList().erase(CI);
92}
93