intel/llvm
1
0
Fork 0
mirror of https://github.com/intel/llvm.git synced 2026-01-19 09:31:59 +08:00
Code Issues Packages Projects Releases Wiki Activity

Revert r282920 "X86: Allow conditional tail calls in Win64 "leaf" functions (PR26302)"

Browse Source 
This is suspected to cause a miscompile in Chromium. Reverting while
investigating.

llvm-svn: 283329
This commit is contained in:
Hans Wennborg
2016-10-05 15:39:27 +00:00
parent 7b8bb53e94
commit c26c03d911
3 changed files with 8 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

5
llvm/lib/Target/X86/X86ExpandPseudo.cpp
View File

@@ -122,9 +122,8 @@ bool X86ExpandPseudo::ExpandMI(MachineBasicBlock &MBB,
Op = X86::TAILJMPd_CC;
break;
case X86::TCRETURNdi64cc:
assert(!MBB.getParent()->hasWinCFI() &&
"Conditional tail calls confuse "
"the Win64 unwinder.");
assert(!IsWin64 && "Conditional tail calls confuse the Win64 unwinder.");
// TODO: We could do it for Win64 "leaf" functions though; PR30337.
Op = X86::TAILJMPd64_CC;
break;
default:

7
llvm/lib/Target/X86/X86InstrInfo.cpp
View File

@@ -4277,9 +4277,9 @@ bool X86InstrInfo::canMakeTailCallConditional(
return false;
}
const MachineFunction *MF = TailCall.getParent()->getParent();
if (Subtarget.isTargetWin64() && MF->hasWinCFI()) {
if (Subtarget.isTargetWin64()) {
// Conditional tail calls confuse the Win64 unwinder.
// TODO: Allow them for "leaf" functions; PR30337.
return false;
}
@@ -4289,7 +4289,8 @@ bool X86InstrInfo::canMakeTailCallConditional(
return false;
}
const X86MachineFunctionInfo *X86FI = MF->getInfo<X86MachineFunctionInfo>();
const X86MachineFunctionInfo *X86FI =
TailCall.getParent()->getParent()->getInfo<X86MachineFunctionInfo>();
if (X86FI->getTCReturnAddrDelta() != 0 ||
TailCall.getOperand(1).getImm() != 0) {
// A conditional tail call cannot do any stack adjustment.

27
llvm/test/CodeGen/X86/conditional-tailcall.ll
View File

@@ -1,6 +1,5 @@
; RUN: llc < %s -mtriple=i686-linux -show-mc-encoding | FileCheck -check-prefix=CHECK %s
; RUN: llc < %s -mtriple=x86_64-linux -show-mc-encoding | FileCheck -check-prefix=CHECK %s
; RUN: llc < %s -mtriple=x86_64-win32 -show-mc-encoding | FileCheck -check-prefix=CHECK -check-prefix=WIN64 %s
; RUN: llc < %s -mtriple=i686-linux -show-mc-encoding | FileCheck %s
; RUN: llc < %s -mtriple=x86_64-linux -show-mc-encoding | FileCheck %s
declare void @foo()
declare void @bar()
@@ -24,28 +23,6 @@ bb2:
; CHECK: jmp foo
}
define void @f_non_leaf(i32 %x, i32 %y) optsize {
entry:
; Force %ebx to be spilled on the stack, turning this into
; not a "leaf" function for Win64.
tail call void asm sideeffect "", "~{ebx}"()
%p = icmp eq i32 %x, %y
br i1 %p, label %bb1, label %bb2
bb1:
tail call void @foo()
ret void
bb2:
tail call void @bar()
ret void
; CHECK-LABEL: f_non_leaf:
; WIN64-NOT: je foo
; WIN64-NOT: jne bar
; WIN64: jne
; WIN64: jmp foo
; WIN64: jmp bar
}
declare x86_thiscallcc zeroext i1 @baz(i8*, i32)
define x86_thiscallcc zeroext i1 @BlockPlacementTest(i8* %this, i32 %x) optsize {