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Change stack probing code for MingW. 

Since gcc 4.6 the compiler uses ___chkstk_ms which has the same semantics as the
MS CRT function __chkstk. This simplifies the prologue generation a bit.

Reviewed by Rafael Espíndola. 

llvm-svn: 197205
This commit is contained in:
Kai Nacke 2013-12-13 05:37:05 +00:00
parent 3fded3cf00
commit 87b23aec08
3 changed files with 13 additions and 15 deletions
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16
llvm/lib/Target/X86/X86FrameLowering.cpp
View File

@ -608,14 +608,12 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
// virtual memory manager are allocated in correct sequence.
if (NumBytes >= 4096 && STI.isOSWindows() && !STI.isTargetMacho()) {
const char *StackProbeSymbol;
bool isSPUpdateNeeded = false;
if (Is64Bit) {
if (STI.isTargetCygMing())
StackProbeSymbol = "___chkstk";
else {
if (STI.isTargetCygMing()) {
StackProbeSymbol = "___chkstk_ms";
} else {
StackProbeSymbol = "__chkstk";
isSPUpdateNeeded = true;
}
} else if (STI.isTargetCygMing())
StackProbeSymbol = "_alloca";
@ -657,15 +655,15 @@ void X86FrameLowering::emitPrologue(MachineFunction &MF) const {
.addReg(X86::EFLAGS, RegState::Define | RegState::Implicit)
.setMIFlag(MachineInstr::FrameSetup);
// MSVC x64's __chkstk does not adjust %rsp itself.
// It also does not clobber %rax so we can reuse it when adjusting %rsp.
if (isSPUpdateNeeded) {
if (Is64Bit) {
// MSVC x64's __chkstk and cygwin/mingw's ___chkstk_ms do not adjust %rsp
// themself. It also does not clobber %rax so we can reuse it when
// adjusting %rsp.
BuildMI(MBB, MBBI, DL, TII.get(X86::SUB64rr), StackPtr)
.addReg(StackPtr)
.addReg(X86::RAX)
.setMIFlag(MachineInstr::FrameSetup);
}
if (isEAXAlive) {
// Restore EAX
MachineInstr *MI = addRegOffset(BuildMI(MF, DL, TII.get(X86::MOV32rm),

6
llvm/test/CodeGen/X86/win64_alloca_dynalloca.ll
View File

@ -12,11 +12,11 @@ entry:
%buf0 = alloca i8, i64 4096, align 1
; ___chkstk must adjust %rsp.
; ___chkstk_ms does not adjust %rsp.
; M64: movq %rsp, %rbp
; M64: $4096, %rax
; M64: callq ___chkstk
; M64-NOT: %rsp
; M64: callq ___chkstk_ms
; M64: subq %rax, %rsp
; __chkstk does not adjust %rsp.
; W64: movq %rsp, %rbp

6
llvm/test/CodeGen/X86/win_chkstk.ll
View File

@ -17,7 +17,7 @@ entry:
; WIN_X32: calll __chkstk
; WIN_X64: callq __chkstk
; MINGW_X32: calll __alloca
; MINGW_X64: callq ___chkstk
; MINGW_X64: callq ___chkstk_ms
; LINUX-NOT: call __chkstk
%array4096 = alloca [4096 x i8], align 16 ; <[4096 x i8]*> [#uses=0]
ret i32 0
@ -36,7 +36,7 @@ entry:
; WIN_X64: ret
; MINGW_X64: # BB#0:
; MINGW_X64-NOT: callq _alloca
; MINGW_X64-NOT: callq ___chkstk_ms
; MINGW_X64: ret
; LINUX: # BB#0:
@ -53,7 +53,7 @@ entry:
; WIN_X32: calll __chkstk
; WIN_X64: callq __chkstk
; MINGW_X32: calll __alloca
; MINGW_X64: callq ___chkstk
; MINGW_X64: callq ___chkstk_ms
; LINUX-NOT: call __chkstk
%array4096 = alloca [4096 x i8], align 16 ; <[4096 x i8]*> [#uses=0]
ret i32 0