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Fix for PR30687. Avoid dereferencing MBB.end().

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We don't need to return a MachineInstr* from these stack probe insertion
calls anyway. If we ever need to add it back, we can return an iterator
instead.

Based on a patch by David Kreitzer

This bug is a consequence of

r279314 | dexonsmith | 2016-08-19 13:40:12 -0700 (Fri, 19 Aug 2016) | 110 lines

We hit the "Assertion `!NodePtr->isKnownSentinel()' failed" assertion,
but only when inserting a stack probe call at the end of an MBB, which
isn't necessarily a common situation.

Differential Revision: https://reviews.llvm.org/D25566

llvm-svn: 284130
This commit is contained in:
Reid Kleckner 2016-10-13 15:48:48 +00:00
parent d7954a6a21
commit 46c5ea7083
3 changed files with 48 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
lib/Target/X86/X86FrameLowering.cpp
View File

@ -447,20 +447,19 @@ void X86FrameLowering::emitCalleeSavedFrameMoves(
}
}
MachineInstr *X86FrameLowering::emitStackProbe(MachineFunction &MF,
void X86FrameLowering::emitStackProbe(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const {
const DebugLoc &DL, bool InProlog) const {
const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
if (STI.isTargetWindowsCoreCLR()) {
if (InProlog) {
return emitStackProbeInlineStub(MF, MBB, MBBI, DL, true);
emitStackProbeInlineStub(MF, MBB, MBBI, DL, true);
} else {
return emitStackProbeInline(MF, MBB, MBBI, DL, false);
emitStackProbeInline(MF, MBB, MBBI, DL, false);
}
} else {
return emitStackProbeCall(MF, MBB, MBBI, DL, InProlog);
emitStackProbeCall(MF, MBB, MBBI, DL, InProlog);
}
}
@ -489,9 +488,11 @@ void X86FrameLowering::inlineStackProbe(MachineFunction &MF,
}
}
MachineInstr *X86FrameLowering::emitStackProbeInline(
MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL, bool InProlog) const {
void X86FrameLowering::emitStackProbeInline(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const {
const X86Subtarget &STI = MF.getSubtarget<X86Subtarget>();
assert(STI.is64Bit() && "different expansion needed for 32 bit");
assert(STI.isTargetWindowsCoreCLR() && "custom expansion expects CoreCLR");
@ -701,13 +702,13 @@ MachineInstr *X86FrameLowering::emitStackProbeInline(
}
// Possible TODO: physreg liveness for InProlog case.
return &*ContinueMBBI;
}
MachineInstr *X86FrameLowering::emitStackProbeCall(
MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL, bool InProlog) const {
void X86FrameLowering::emitStackProbeCall(MachineFunction &MF,
MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const {
bool IsLargeCodeModel = MF.getTarget().getCodeModel() == CodeModel::Large;
unsigned CallOp;
@ -765,11 +766,9 @@ MachineInstr *X86FrameLowering::emitStackProbeCall(
for (++ExpansionMBBI; ExpansionMBBI != MBBI; ++ExpansionMBBI)
ExpansionMBBI->setFlag(MachineInstr::FrameSetup);
}
return &*MBBI;
}
MachineInstr *X86FrameLowering::emitStackProbeInlineStub(
void X86FrameLowering::emitStackProbeInlineStub(
MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL, bool InProlog) const {
@ -777,8 +776,6 @@ MachineInstr *X86FrameLowering::emitStackProbeInlineStub(
BuildMI(MBB, MBBI, DL, TII.get(X86::CALLpcrel32))
.addExternalSymbol("__chkstk_stub");
return &*MBBI;
}
static unsigned calculateSetFPREG(uint64_t SPAdjust) {

24
lib/Target/X86/X86FrameLowering.h
View File

@ -49,11 +49,10 @@ public:
/// Emit target stack probe code. This is required for all
/// large stack allocations on Windows. The caller is required to materialize
/// the number of bytes to probe in RAX/EAX. Returns instruction just
/// after the expansion.
MachineInstr *emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool InProlog) const;
/// the number of bytes to probe in RAX/EAX.
void emitStackProbe(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
bool InProlog) const;
/// Replace a StackProbe inline-stub with the actual probe code inline.
void inlineStackProbe(MachineFunction &MF,
@ -179,22 +178,19 @@ private:
uint64_t calculateMaxStackAlign(const MachineFunction &MF) const;
/// Emit target stack probe as a call to a helper function
MachineInstr *emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool InProlog) const;
void emitStackProbeCall(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI, const DebugLoc &DL,
bool InProlog) const;
/// Emit target stack probe as an inline sequence.
MachineInstr *emitStackProbeInline(MachineFunction &MF,
MachineBasicBlock &MBB,
void emitStackProbeInline(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL, bool InProlog) const;
/// Emit a stub to later inline the target stack probe.
MachineInstr *emitStackProbeInlineStub(MachineFunction &MF,
MachineBasicBlock &MBB,
void emitStackProbeInlineStub(MachineFunction &MF, MachineBasicBlock &MBB,
MachineBasicBlock::iterator MBBI,
const DebugLoc &DL,
bool InProlog) const;
const DebugLoc &DL, bool InProlog) const;
/// Aligns the stack pointer by ANDing it with -MaxAlign.
void BuildStackAlignAND(MachineBasicBlock &MBB,

17
test/CodeGen/X86/win_chkstk.ll
View File

@ -63,3 +63,20 @@ entry:
%array4096 = alloca [4096 x i8], align 16 ; <[4096 x i8]*> [#uses=0]
ret i32 0
}
; PR30687: Avoid crashing when inserting a __chkstk call at the end of an MBB.
define void @dont_crash() {
entry:
; WIN_X32: calll __chkstk
; WIN_X64: callq __chkstk
; WIN64_LARGE: movabsq $__chkstk, %r11
; WIN64_LARGE: callq *%r11
; MINGW_X32: calll __alloca
; MINGW_X64: callq ___chkstk_ms
; LINUX-NOT: call __chkstk
%buffer = alloca [4096 x i8]
br label %ret
ret:
ret void
}