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[BOLT][X86] Fix getTargetSymbol() (#133834)

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In 96e5ee2, I inadvertently broke the way non-trivial symbol references
got updated from non-optimized code. The breakage was a consequence of
`getTargetSymbol(MCExpr *)` not returning a symbol when the parameter
was a binary expression. Fix `getTargetSymbol()` to cover such cases.
This commit is contained in:
Maksim Panchenko
2025-03-31 18:31:33 -07:00
committed by GitHub
parent 508a6b2e01
commit b2d272ccfb
5 changed files with 42 additions and 25 deletions
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6
bolt/include/bolt/Core/MCPlusBuilder.h
View File

@@ -1266,7 +1266,11 @@ public:
/// Return MCSymbol extracted from the expression.
virtual const MCSymbol *getTargetSymbol(const MCExpr *Expr) const {
if (auto *SymbolRefExpr = dyn_cast<const MCSymbolRefExpr>(Expr))
if (auto *BinaryExpr = dyn_cast<const MCBinaryExpr>(Expr))
return getTargetSymbol(BinaryExpr->getLHS());
auto *SymbolRefExpr = dyn_cast<const MCSymbolRefExpr>(Expr);
if (SymbolRefExpr && SymbolRefExpr->getKind() == MCSymbolRefExpr::VK_None)
return &SymbolRefExpr->getSymbol();
return nullptr;

12
bolt/lib/Target/AArch64/AArch64MCPlusBuilder.cpp
View File

@@ -862,20 +862,12 @@ public:
if (AArchExpr && AArchExpr->getSubExpr())
return getTargetSymbol(AArchExpr->getSubExpr());
auto *BinExpr = dyn_cast<MCBinaryExpr>(Expr);
if (BinExpr)
return getTargetSymbol(BinExpr->getLHS());
auto *SymExpr = dyn_cast<MCSymbolRefExpr>(Expr);
if (SymExpr && SymExpr->getKind() == MCSymbolRefExpr::VK_None)
return &SymExpr->getSymbol();
return nullptr;
return MCPlusBuilder::getTargetSymbol(Expr);
}
const MCSymbol *getTargetSymbol(const MCInst &Inst,
unsigned OpNum = 0) const override {
if (!getSymbolRefOperandNum(Inst, OpNum))
if (!OpNum && !getSymbolRefOperandNum(Inst, OpNum))
return nullptr;
const MCOperand &Op = Inst.getOperand(OpNum);

10
bolt/lib/Target/RISCV/RISCVMCPlusBuilder.cpp
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@@ -338,15 +338,7 @@ public:
if (RISCVExpr && RISCVExpr->getSubExpr())
return getTargetSymbol(RISCVExpr->getSubExpr());
auto *BinExpr = dyn_cast<MCBinaryExpr>(Expr);
if (BinExpr)
return getTargetSymbol(BinExpr->getLHS());
auto *SymExpr = dyn_cast<MCSymbolRefExpr>(Expr);
if (SymExpr && SymExpr->getKind() == MCSymbolRefExpr::VK_None)
return &SymExpr->getSymbol();
return nullptr;
return MCPlusBuilder::getTargetSymbol(Expr);
}
const MCSymbol *getTargetSymbol(const MCInst &Inst,

6
bolt/lib/Target/X86/X86MCPlusBuilder.cpp
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@@ -1796,11 +1796,7 @@ public:
if (!Op.isExpr())
return nullptr;
auto *SymExpr = dyn_cast<MCSymbolRefExpr>(Op.getExpr());
if (!SymExpr || SymExpr->getKind() != MCSymbolRefExpr::VK_None)
return nullptr;
return &SymExpr->getSymbol();
return MCPlusBuilder::getTargetSymbol(Op.getExpr());
}
bool analyzeBranch(InstructionIterator Begin, InstructionIterator End,

33
bolt/test/X86/lite-mode-target-expr.s Normal file
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@@ -0,0 +1,33 @@
## Check that llvm-bolt properly updates references in unoptimized code when
## such references are non-trivial expressions.
# RUN: %clang %cflags %s -o %t.exe -Wl,-q -no-pie
# RUN: llvm-bolt %t.exe -o %t.bolt --funcs=_start
# RUN: llvm-objdump -d --disassemble-symbols=_start %t.bolt > %t.out
# RUN: llvm-objdump -d --disassemble-symbols=cold %t.bolt >> %t.out
# RUN: FileCheck %s < %t.out
## _start() will be optimized and assigned a new address.
# CHECK: [[#%x,ADDR:]] <_start>:
## cold() is not optimized, but references to _start are updated.
# CHECK-LABEL: <cold>:
# CHECK-NEXT: movl $0x[[#ADDR - 1]], %ecx
# CHECK-NEXT: movl $0x[[#ADDR]], %ecx
# CHECK-NEXT: movl $0x[[#ADDR + 1]], %ecx
.text
.globl cold
.type cold, %function
cold:
movl $_start-1, %ecx
movl $_start, %ecx
movl $_start+1, %ecx
ret
.size cold, .-cold
.globl _start
.type _start, %function
_start:
ret
.size _start, .-_start