[llvm-commits] [llvm] r163853 - in /llvm/trunk: include/llvm/MC/MCMachObjectWriter.h lib/MC/MachObjectWriter.cpp

[Jim Grosbach]

Aha! Found it. r163854 tests this as well as the no_dead_strip attribute. I goofed and didn't explicitly call that out in the commit message for that patch. Sorry about that.

-Jim

On Sep 19, 2012, at 2:09 PM, Jim Grosbach <grosbach at apple.com> wrote:

> Huh. I thought I had, but there's certainly not one there. Probably pilot error on the "git add" on my end or something.
> 
> Thanks for the reminder! Will fix.
> 
> -Jim
> 
> On Sep 19, 2012, at 1:53 PM, Rafael Espíndola <rafael.espindola at gmail.com> wrote:
> 
>> Can you add a test?
>> 
>> On 13 September 2012 19:11, Jim Grosbach <grosbach at apple.com> wrote:
>>> Author: grosbach
>>> Date: Thu Sep 13 18:11:25 2012
>>> New Revision: 163853
>>> 
>>> URL: http://llvm.org/viewvc/llvm-project?rev=163853&view=rev
>>> Log:
>>> MachO: Correctly mark symbol-difference variables as N_ABS.
>>> 
>>> .set a, b - c + CONSTANT
>>> d = b - c + CONSTANT
>>> 
>>> Both 'a' and 'd' should be marked as absolute symbols (N_ABS).
>>> 
>>> rdar://12219394
>>> 
>>> Modified:
>>>   llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
>>>   llvm/trunk/lib/MC/MachObjectWriter.cpp
>>> 
>>> Modified: llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCMachObjectWriter.h?rev=163853&r1=163852&r2=163853&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/MC/MCMachObjectWriter.h (original)
>>> +++ llvm/trunk/include/llvm/MC/MCMachObjectWriter.h Thu Sep 13 18:11:25 2012
>>> @@ -233,6 +233,8 @@
>>>  void computeSectionAddresses(const MCAssembler &Asm,
>>>                               const MCAsmLayout &Layout);
>>> 
>>> +  void markAbsoluteVariableSymbols(MCAssembler &Asm,
>>> +                                   const MCAsmLayout &Layout);
>>>  void ExecutePostLayoutBinding(MCAssembler &Asm, const MCAsmLayout &Layout);
>>> 
>>>  virtual bool IsSymbolRefDifferenceFullyResolvedImpl(const MCAssembler &Asm,
>>> 
>>> Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
>>> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=163853&r1=163852&r2=163853&view=diff
>>> ==============================================================================
>>> --- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
>>> +++ llvm/trunk/lib/MC/MachObjectWriter.cpp Thu Sep 13 18:11:25 2012
>>> @@ -68,6 +68,11 @@
>>> 
>>>  // If this is a variable, then recursively evaluate now.
>>>  if (S.isVariable()) {
>>> +    if (const MCConstantExpr *C =
>>> +          dyn_cast<const MCConstantExpr>(S.getVariableValue()))
>>> +      return C->getValue();
>>> +
>>> +
>>>    MCValue Target;
>>>    if (!S.getVariableValue()->EvaluateAsRelocatable(Target, Layout))
>>>      report_fatal_error("unable to evaluate offset for variable '" +
>>> @@ -315,11 +320,7 @@
>>> 
>>>  // Compute the symbol address.
>>>  if (Symbol.isDefined()) {
>>> -    if (Symbol.isAbsolute()) {
>>> -      Address = cast<MCConstantExpr>(Symbol.getVariableValue())->getValue();
>>> -    } else {
>>> -      Address = getSymbolAddress(&Data, Layout);
>>> -    }
>>> +    Address = getSymbolAddress(&Data, Layout);
>>>  } else if (Data.isCommon()) {
>>>    // Common symbols are encoded with the size in the address
>>>    // field, and their alignment in the flags.
>>> @@ -557,6 +558,26 @@
>>>  }
>>> }
>>> 
>>> +void MachObjectWriter::markAbsoluteVariableSymbols(MCAssembler &Asm,
>>> +                                                   const MCAsmLayout &Layout) {
>>> +  for (MCAssembler::symbol_iterator i = Asm.symbol_begin(),
>>> +                                    e = Asm.symbol_end();
>>> +      i != e; ++i) {
>>> +    MCSymbolData &SD = *i;
>>> +    if (!SD.getSymbol().isVariable())
>>> +      continue;
>>> +
>>> +    // Is the variable is a symbol difference (SA - SB + C) expression,
>>> +    // and neither symbol is external, mark the variable as absolute.
>>> +    const MCExpr *Expr = SD.getSymbol().getVariableValue();
>>> +    MCValue Value;
>>> +    if (Expr->EvaluateAsRelocatable(Value, Layout)) {
>>> +      if (Value.getSymA() && Value.getSymB())
>>> +        const_cast<MCSymbol*>(&SD.getSymbol())->setAbsolute();
>>> +    }
>>> +  }
>>> +}
>>> +
>>> void MachObjectWriter::ExecutePostLayoutBinding(MCAssembler &Asm,
>>>                                                const MCAsmLayout &Layout) {
>>>  computeSectionAddresses(Asm, Layout);
>>> @@ -564,6 +585,10 @@
>>>  // Create symbol data for any indirect symbols.
>>>  BindIndirectSymbols(Asm);
>>> 
>>> +  // Mark symbol difference expressions in variables (from .set or = directives)
>>> +  // as absolute.
>>> +  markAbsoluteVariableSymbols(Asm, Layout);
>>> +
>>>  // Compute symbol table information and bind symbol indices.
>>>  ComputeSymbolTable(Asm, StringTable, LocalSymbolData, ExternalSymbolData,
>>>                     UndefinedSymbolData);
>>> 
>>> 
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