llvm-6502/lib/MC/MCFixup.cpp
Kaelyn Takata de2b2a32f4 Fix up MCFixup::getAccessVariant to handle unary expressions.
This allows correct relocations to be generated for a symbolic
address that is being adjusted by a negative constant. Since r204294,
such expressions have triggered undefined behavior when LLVM was built
without assertions.

Credit goes to Rafael for this patch; I'm submitting it on his behalf
as he is on vacation this week.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206192 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-14 16:50:22 +00:00

43 lines
1.3 KiB
C++

//===- MCFixup.cpp - Assembly Fixup Implementation ------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/MC/MCFixup.h"
using namespace llvm;
static MCSymbolRefExpr::VariantKind getAccessVariant(const MCExpr *Expr) {
switch (Expr->getKind()) {
case MCExpr::Unary: {
const MCUnaryExpr *UE = cast<MCUnaryExpr>(Expr);
assert(getAccessVariant(UE->getSubExpr()) == MCSymbolRefExpr::VK_None);
return MCSymbolRefExpr::VK_None;
}
case MCExpr::Target:
llvm_unreachable("unsupported");
case MCExpr::Constant:
return MCSymbolRefExpr::VK_None;
case MCExpr::SymbolRef: {
const MCSymbolRefExpr *SRE = cast<MCSymbolRefExpr>(Expr);
return SRE->getKind();
}
case MCExpr::Binary: {
const MCBinaryExpr *ABE = cast<MCBinaryExpr>(Expr);
assert(getAccessVariant(ABE->getRHS()) == MCSymbolRefExpr::VK_None);
return getAccessVariant(ABE->getLHS());
}
}
llvm_unreachable("unknown MCExpr kind");
}
MCSymbolRefExpr::VariantKind MCFixup::getAccessVariant() const {
return ::getAccessVariant(getValue());
}