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MS ABI: Implement proper support for setjmp 

On targets which use the MSVCRT, setjmp is a macro which expands to
_setjmp or _setjmpex.

_setjmp and _setjmpex have a secret, hidden argument which is not listed
in the function prototype on X64 and WoA.  This hidden argument always
seems to be the frame pointer.

_setjmpex isn't used on X86, _setjmp is magically replaced with a call
to _setjmp3.  The second argument is zero for 'normal' setjmp/longjmp
pairs, otherwise it is a count of additional variadic arguments.  This
is used when setjmp appears inside of a try or __try.

It is not safe to use a pointer to setjmp because _setjmp, _setjmpex and
_setmp3 are not compatible with setjmp.

llvm-svn: 227426
This commit is contained in:
David Majnemer 2015-01-29 09:29:21 +00:00
parent b9bf14c549
commit 310e3a8f60
3 changed files with 84 additions and 0 deletions
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3
clang/include/clang/Basic/Builtins.def
View File

@ -710,6 +710,9 @@ LANGBUILTIN(__noop, "i.", "n", ALL_MS_LANGUAGES)
LANGBUILTIN(__readfsdword, "ULiULi", "n", ALL_MS_LANGUAGES)
LANGBUILTIN(__va_start, "vc**.", "nt", ALL_MS_LANGUAGES)
// Microsoft library builtins.
LIBBUILTIN(_setjmpex, "iJ", "fj", "setjmpex.h", ALL_MS_LANGUAGES)
// C99 library functions
// C99 stdlib.h
LIBBUILTIN(abort, "v", "fr", "stdlib.h", ALL_LANGUAGES)

52
clang/lib/CodeGen/CGBuiltin.cpp
View File

@ -21,6 +21,7 @@
#include "clang/Basic/TargetInfo.h"
#include "clang/CodeGen/CGFunctionInfo.h"
#include "llvm/ADT/StringExtras.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/IR/Intrinsics.h"
@ -1662,6 +1663,57 @@ RValue CodeGenFunction::EmitBuiltinExpr(const FunctionDecl *FD,
case Builtin::BI__exception_info:
case Builtin::BI_exception_info:
return RValue::get(EmitSEHExceptionInfo());
case Builtin::BI_setjmpex: {
if (getTarget().getTriple().isOSMSVCRT()) {
llvm::Type *ArgTypes[] = {Int8PtrTy, Int8PtrTy};
llvm::AttributeSet ReturnsTwiceAttr =
AttributeSet::get(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
llvm::Attribute::ReturnsTwice);
llvm::Constant *SetJmpEx = CGM.CreateRuntimeFunction(
llvm::FunctionType::get(IntTy, ArgTypes, /*isVarArg=*/false),
"_setjmpex", ReturnsTwiceAttr);
llvm::Value *Buf =
Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)), Int8PtrTy);
llvm::Value *FrameAddr =
Builder.CreateCall(CGM.getIntrinsic(Intrinsic::frameaddress),
ConstantInt::get(Int32Ty, 0));
llvm::Value *Args[] = {Buf, FrameAddr};
llvm::CallSite CS = EmitRuntimeCallOrInvoke(SetJmpEx, Args);
CS.setAttributes(ReturnsTwiceAttr);
return RValue::get(CS.getInstruction());
}
}
case Builtin::BI_setjmp: {
if (getTarget().getTriple().isOSMSVCRT()) {
llvm::AttributeSet ReturnsTwiceAttr =
AttributeSet::get(getLLVMContext(), llvm::AttributeSet::FunctionIndex,
llvm::Attribute::ReturnsTwice);
llvm::Value *Buf =
Builder.CreateBitCast(EmitScalarExpr(E->getArg(0)), Int8PtrTy);
llvm::CallSite CS;
if (getTarget().getTriple().getArch() == llvm::Triple::x86) {
llvm::Type *ArgTypes[] = {Int8PtrTy, IntTy};
llvm::Constant *SetJmp3 = CGM.CreateRuntimeFunction(
llvm::FunctionType::get(IntTy, ArgTypes, /*isVarArg=*/true),
"_setjmp3", ReturnsTwiceAttr);
llvm::Value *Count = ConstantInt::get(IntTy, 0);
llvm::Value *Args[] = {Buf, Count};
CS = EmitRuntimeCallOrInvoke(SetJmp3, Args);
} else {
llvm::Type *ArgTypes[] = {Int8PtrTy, Int8PtrTy};
llvm::Constant *SetJmp = CGM.CreateRuntimeFunction(
llvm::FunctionType::get(IntTy, ArgTypes, /*isVarArg=*/false),
"_setjmp", ReturnsTwiceAttr);
llvm::Value *FrameAddr =
Builder.CreateCall(CGM.getIntrinsic(Intrinsic::frameaddress),
ConstantInt::get(Int32Ty, 0));
llvm::Value *Args[] = {Buf, FrameAddr};
CS = EmitRuntimeCallOrInvoke(SetJmp, Args);
}
CS.setAttributes(ReturnsTwiceAttr);
return RValue::get(CS.getInstruction());
}
}
}
// If this is an alias for a lib function (e.g. __builtin_sin), emit

29
clang/test/CodeGen/ms-setjmp.c Normal file
View File

@ -0,0 +1,29 @@
// RUN: %clang_cc1 -fms-extensions -triple i686-windows-msvc -emit-llvm %s -o - | FileCheck --check-prefix=I386 %s
// RUN: %clang_cc1 -fms-extensions -triple x86_64-windows-msvc -emit-llvm %s -o - | FileCheck --check-prefix=X64 %s
typedef char jmp_buf[1];
int _setjmp(jmp_buf env);
int _setjmpex(jmp_buf env);
jmp_buf jb;
int test_setjmp() {
return _setjmp(jb);
// I386-LABEL: define i32 @test_setjmp
// I386: %[[call:.*]] = call i32 (i8*, i32, ...)* @_setjmp3(i8* getelementptr inbounds ([1 x i8]* @jb, i32 0, i32 0), i32 0)
// I386-NEXT: ret i32 %[[call]]
// X64-LABEL: define i32 @test_setjmp
// X64: %[[addr:.*]] = call i8* @llvm.frameaddress(i32 0)
// X64: %[[call:.*]] = call i32 @_setjmp(i8* getelementptr inbounds ([1 x i8]* @jb, i32 0, i32 0), i8* %[[addr]])
// X64-NEXT: ret i32 %[[call]]
}
int test_setjmpex() {
return _setjmpex(jb);
// X64-LABEL: define i32 @test_setjmpex
// X64: %[[addr:.*]] = call i8* @llvm.frameaddress(i32 0)
// X64: %[[call:.*]] = call i32 @_setjmpex(i8* getelementptr inbounds ([1 x i8]* @jb, i32 0, i32 0), i8* %[[addr]])
// X64-NEXT: ret i32 %[[call]]
}