http://llvm.org/bugs/show_bug.cgi?id=5005
Summary: Win64 stack corruption when spilling callee saved XMM
registers.
Product: libraries
Version: trunk
Platform: PC
OS/Version: Windows XP
Status: NEW
Severity: normal
Priority: P2
Component: Backend: X86
AssignedTo: [email protected]
ReportedBy: [email protected]
CC: [email protected]
If callee saved XMM registers get spilled/restored in the prologue/epilogue,
the instruction walker that skips the push/pop instructions will fail to
recognize the movaps/movups instruction causing the stack update to be
incorrectly placed.
In X86RegisterInfo::emitPrologue:
while (MBBI != MBB.end() &&
(MBBI->getOpcode() == X86::PUSH32r ||
MBBI->getOpcode() == X86::PUSH64r)) {
PushedRegs = true;
++MBBI;
This code should probably skip X86::MOVAPSmr instructions.
Failing to recognize XMM saves/restores will produce the following incorrect
code:
pushq %rbp
movq %rsp, %rbp
subq $328, %rsp # <=== Incorrect position
movups %xmm7, -80(%rbp)
movups %xmm6, -64(%rbp)
pushq %r15
pushq %r14
pushq %rsi
pushq %rdi
pushq %rbx
The correct code should be:
pushq %rbp
movq %rsp, %rbp
movups %xmm7, -80(%rbp)
movups %xmm6, -64(%rbp)
pushq %r15
pushq %r14
pushq %rsi
pushq %rdi
pushq %rbx
subq $328, %rsp # <=== OK
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