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[XRay][compiler-rt][x86_64] Preserve flags in x86_64 trampolines. #89452

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Merged
merged 1 commit into from
May 27, 2024
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[XRay][compiler-rt][x86_64] Preserve flags in x86_64 trampolines. #89452

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15 changes: 7 additions & 8 deletions compiler-rt/lib/xray/xray_trampoline_x86_64.S
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Original file line number Diff line number Diff line change
Expand Up @@ -40,7 +40,7 @@
CFI_ADJUST_CFA_OFFSET(-8)
.endm

// This macro should keep the stack aligned to 16 bytes.
// This macro should lower the stack pointer by an odd multiple of 8.
.macro SAVE_REGISTERS
pushfq
CFI_ADJUST_CFA_OFFSET(8)
Expand Down Expand Up @@ -70,7 +70,6 @@
movq %r15, 0(%rsp)
.endm

// This macro should keep the stack aligned to 16 bytes.
.macro RESTORE_REGISTERS
movq 232(%rsp), %rbp
movupd 216(%rsp), %xmm0
Expand Down Expand Up @@ -117,8 +116,8 @@
# LLVM-MCA-BEGIN __xray_FunctionEntry
ASM_SYMBOL(__xray_FunctionEntry):
CFI_STARTPROC
ALIGN_STACK_16B
SAVE_REGISTERS
ALIGN_STACK_16B

// This load has to be atomic, it's concurrent with __xray_patch().
// On x86/amd64, a simple (type-aligned) MOV instruction is enough.
Expand All @@ -132,8 +131,8 @@ ASM_SYMBOL(__xray_FunctionEntry):
callq *%rax

LOCAL_LABEL(tmp0):
RESTORE_REGISTERS
RESTORE_STACK_ALIGNMENT
RESTORE_REGISTERS
retq
# LLVM-MCA-END
ASM_SIZE(__xray_FunctionEntry)
Expand Down Expand Up @@ -193,8 +192,8 @@ LOCAL_LABEL(tmp2):
# LLVM-MCA-BEGIN __xray_FunctionTailExit
ASM_SYMBOL(__xray_FunctionTailExit):
CFI_STARTPROC
ALIGN_STACK_16B
SAVE_REGISTERS
ALIGN_STACK_16B

movq ASM_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)(%rip), %rax
testq %rax,%rax
Expand All @@ -205,8 +204,8 @@ ASM_SYMBOL(__xray_FunctionTailExit):
callq *%rax

LOCAL_LABEL(tmp4):
RESTORE_REGISTERS
RESTORE_STACK_ALIGNMENT
RESTORE_REGISTERS
retq
# LLVM-MCA-END
ASM_SIZE(__xray_FunctionTailExit)
Expand All @@ -221,8 +220,8 @@ LOCAL_LABEL(tmp4):
# LLVM-MCA-BEGIN __xray_ArgLoggerEntry
ASM_SYMBOL(__xray_ArgLoggerEntry):
CFI_STARTPROC
ALIGN_STACK_16B
SAVE_REGISTERS
ALIGN_STACK_16B

// Again, these function pointer loads must be atomic; MOV is fine.
movq ASM_SYMBOL(_ZN6__xray13XRayArgLoggerE)(%rip), %rax
Expand All @@ -248,8 +247,8 @@ LOCAL_LABEL(arg1entryLog):
callq *%rax

LOCAL_LABEL(arg1entryFail):
RESTORE_REGISTERS
RESTORE_STACK_ALIGNMENT
RESTORE_REGISTERS
retq
# LLVM-MCA-END
ASM_SIZE(__xray_ArgLoggerEntry)
Expand Down