[llvm] r198590 - MC: Fatally error if subtraction operand is bad

[Rafael Espíndola]

testcase?

On 5 January 2014 23:39, David Majnemer <david.majnemer at gmail.com> wrote:
> Author: majnemer
> Date: Mon Jan  6 01:39:46 2014
> New Revision: 198590
>
> URL: http://llvm.org/viewvc/llvm-project?rev=198590&view=rev
> Log:
> MC: Fatally error if subtraction operand is bad
>
> Instead of crashing, raise an error when a subtraction expression
> involves an undefined symbol.
>
> This fixes PR18375.
>
> Modified:
>     llvm/trunk/lib/MC/ELFObjectWriter.cpp
>     llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
>
> Modified: llvm/trunk/lib/MC/ELFObjectWriter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/ELFObjectWriter.cpp?rev=198590&r1=198589&r2=198590&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/ELFObjectWriter.cpp (original)
> +++ llvm/trunk/lib/MC/ELFObjectWriter.cpp Mon Jan  6 01:39:46 2014
> @@ -720,6 +720,12 @@ void ELFObjectWriter::RecordRelocation(c
>        MCSymbolData &SDB = Asm.getSymbolData(SymbolB);
>        IsPCRel = true;
>
> +      if (!SDB.getFragment())
> +        Asm.getContext().FatalError(
> +            Fixup.getLoc(),
> +            Twine("symbol '") + SymbolB.getName() +
> +                "' can not be undefined in a subtraction expression");
> +
>        // Offset of the symbol in the section
>        int64_t a = Layout.getSymbolOffset(&SDB);
>
>
> Modified: llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp?rev=198590&r1=198589&r2=198590&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp (original)
> +++ llvm/trunk/lib/MC/WinCOFFObjectWriter.cpp Mon Jan  6 01:39:46 2014
> @@ -648,14 +648,25 @@ void WinCOFFObjectWriter::RecordRelocati
>
>    COFFSection *coff_section = SectionMap[&SectionData->getSection()];
>    COFFSymbol *coff_symbol = SymbolMap[&A_SD.getSymbol()];
> -  const MCSymbolRefExpr *SymA = Target.getSymA();
>    const MCSymbolRefExpr *SymB = Target.getSymB();
> -  const bool CrossSection = SymB &&
> -    &SymA->getSymbol().getSection() != &SymB->getSymbol().getSection();
> +  bool CrossSection = false;
>
> -  if (Target.getSymB()) {
> -    const MCSymbol *B = &Target.getSymB()->getSymbol();
> +  if (SymB) {
> +    const MCSymbol *B = &SymB->getSymbol();
>      MCSymbolData &B_SD = Asm.getSymbolData(*B);
> +    if (!B_SD.getFragment())
> +      Asm.getContext().FatalError(
> +          Fixup.getLoc(),
> +          Twine("symbol '") + B->getName() +
> +              "' can not be undefined in a subtraction expression");
> +
> +    if (!A_SD.getFragment())
> +      Asm.getContext().FatalError(
> +          Fixup.getLoc(),
> +          Twine("symbol '") + Symbol.getName() +
> +              "' can not be undefined in a subtraction expression");
> +
> +    CrossSection = &Symbol.getSection() != &B->getSection();
>
>      // Offset of the symbol in the section
>      int64_t a = Layout.getSymbolOffset(&B_SD);
>
>
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