[llvm] r192758 - MC: Better handling of tricky symbol and section names

NAKAMURA Takumi geek4civic at gmail.com
Wed Oct 16 01:29:04 PDT 2013


Hans, excuse me, I have reverted it in r192775.

...Takumi

2013/10/16 Hans Wennborg <hans at hanshq.net>:
> Author: hans
> Date: Tue Oct 15 20:20:40 2013
> New Revision: 192758
>
> URL: http://llvm.org/viewvc/llvm-project?rev=192758&view=rev
> Log:
> MC: Better handling of tricky symbol and section names
>
> Because of win32 mangling, we produce symbol and section names with
> funny characters in them, most notably @ characters.
>
> MC would choke on trying to parse its own assembly output. This patch addresses
> that by:
>
> - Making @ trigger quoting of symbol names
> - Also quote section names in the same way
> - Just parse section names like other identifiers (to allow for quotes)
> - Don't assume @ signifies a symbol variant if it is in a string.
>
> Differential Revision: http://llvm-reviews.chandlerc.com/D1945
>
> Added:
>     llvm/trunk/test/MC/COFF/quoted-names.ll
> Modified:
>     llvm/trunk/lib/MC/MCParser/AsmParser.cpp
>     llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp
>     llvm/trunk/lib/MC/MCSectionCOFF.cpp
>     llvm/trunk/lib/MC/MCSymbol.cpp
>     llvm/trunk/test/CodeGen/X86/coff-feat00.ll
>     llvm/trunk/test/CodeGen/X86/fastcall-correct-mangling.ll
>     llvm/trunk/test/CodeGen/X86/stdcall.ll
>
> Modified: llvm/trunk/lib/MC/MCParser/AsmParser.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/AsmParser.cpp?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCParser/AsmParser.cpp (original)
> +++ llvm/trunk/lib/MC/MCParser/AsmParser.cpp Tue Oct 15 20:20:40 2013
> @@ -792,19 +792,25 @@ bool AsmParser::parsePrimaryExpr(const M
>      EndLoc = SMLoc::getFromPointer(Identifier.end());
>
>      // This is a symbol reference.
> +    StringRef SymbolName = Identifier;
> +    MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
>      std::pair<StringRef, StringRef> Split = Identifier.split('@');
> -    MCSymbol *Sym = getContext().GetOrCreateSymbol(Split.first);
> +
> +    if (Split.first.size() != Identifier.size() &&
> +        FirstTokenKind != AsmToken::String) {
> +      SymbolName = Split.first;
> +      StringRef VariantName = Split.second;
>
> -    // Lookup the symbol variant if used.
> -    MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
> -    if (Split.first.size() != Identifier.size()) {
> -      Variant = MCSymbolRefExpr::getVariantKindForName(Split.second);
> +      // Lookup the symbol variant.
> +      Variant = MCSymbolRefExpr::getVariantKindForName(VariantName);
>        if (Variant == MCSymbolRefExpr::VK_Invalid) {
>          Variant = MCSymbolRefExpr::VK_None;
> -        return TokError("invalid variant '" + Split.second + "'");
> +        return TokError("invalid variant '" + VariantName + "'");
>        }
>      }
>
> +    MCSymbol *Sym = getContext().GetOrCreateSymbol(SymbolName);
> +
>      // If this is an absolute variable reference, substitute it now to preserve
>      // semantics in the face of reassignment.
>      if (Sym->isVariable() && isa<MCConstantExpr>(Sym->getVariableValue())) {
>
> Modified: llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp (original)
> +++ llvm/trunk/lib/MC/MCParser/COFFAsmParser.cpp Tue Oct 15 20:20:40 2013
> @@ -295,12 +295,7 @@ bool COFFAsmParser::ParseSectionSwitch(S
>  }
>
>  bool COFFAsmParser::ParseSectionName(StringRef &SectionName) {
> -  if (!getLexer().is(AsmToken::Identifier))
> -    return true;
> -
> -  SectionName = getTok().getIdentifier();
> -  Lex();
> -  return false;
> +  return getParser().parseIdentifier(SectionName);
>  }
>
>  // .section name [, "flags"]
>
> Modified: llvm/trunk/lib/MC/MCSectionCOFF.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCSectionCOFF.cpp?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCSectionCOFF.cpp (original)
> +++ llvm/trunk/lib/MC/MCSectionCOFF.cpp Tue Oct 15 20:20:40 2013
> @@ -39,6 +39,22 @@ void MCSectionCOFF::setSelection(int Sel
>    Characteristics |= COFF::IMAGE_SCN_LNK_COMDAT;
>  }
>
> +static bool isAcceptableSectionNameChar(char C) {
> +  return (C >= 'a' && C <= 'z') ||
> +         (C >= 'A' && C <= 'Z') ||
> +         (C >= '0' && C <= '9') ||
> +         C == '_' || C == '$' || C == '.';
> +}
> +
> +/// NameNeedsQuoting - Return true if the identifier \p Str needs quotes to be
> +/// syntactically correct.
> +static bool sectionNameNeedsQuoting(StringRef Name) {
> +  for (unsigned i = 0, e = Name.size(); i != e; ++i)
> +    if (!isAcceptableSectionNameChar(Name[i]))
> +      return true;
> +  return false;
> +}
> +
>  void MCSectionCOFF::PrintSwitchToSection(const MCAsmInfo &MAI,
>                                           raw_ostream &OS,
>                                           const MCExpr *Subsection) const {
> @@ -49,7 +65,10 @@ void MCSectionCOFF::PrintSwitchToSection
>      return;
>    }
>
> -  OS << "\t.section\t" << getSectionName() << ",\"";
> +  if (sectionNameNeedsQuoting(getSectionName()))
> +    OS << "\t.section\t" << '"' << getSectionName() << '"' << ",\"";
> +  else
> +    OS << "\t.section\t" << getSectionName() << ",\"";
>    if (getKind().isText())
>      OS << 'x';
>    if (getKind().isWriteable())
>
> Modified: llvm/trunk/lib/MC/MCSymbol.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCSymbol.cpp?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCSymbol.cpp (original)
> +++ llvm/trunk/lib/MC/MCSymbol.cpp Tue Oct 15 20:20:40 2013
> @@ -18,12 +18,10 @@ const MCSection *MCSymbol::AbsolutePseud
>    reinterpret_cast<const MCSection *>(1);
>
>  static bool isAcceptableChar(char C) {
> -  if ((C < 'a' || C > 'z') &&
> -      (C < 'A' || C > 'Z') &&
> -      (C < '0' || C > '9') &&
> -      C != '_' && C != '$' && C != '.' && C != '@')
> -    return false;
> -  return true;
> +  return (C >= 'a' && C <= 'z') ||
> +         (C >= 'A' && C <= 'Z') ||
> +         (C >= '0' && C <= '9') ||
> +         C == '_' || C == '$' || C == '.';
>  }
>
>  /// NameNeedsQuoting - Return true if the identifier \p Str needs quotes to be
>
> Modified: llvm/trunk/test/CodeGen/X86/coff-feat00.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/coff-feat00.ll?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/coff-feat00.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/coff-feat00.ll Tue Oct 15 20:20:40 2013
> @@ -4,4 +4,4 @@ define i32 @foo() {
>    ret i32 0
>  }
>
> -; CHECK: @feat.00 = 1
> +; CHECK: "@feat.00" = 1
>
> Modified: llvm/trunk/test/CodeGen/X86/fastcall-correct-mangling.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fastcall-correct-mangling.ll?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/fastcall-correct-mangling.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/fastcall-correct-mangling.ll Tue Oct 15 20:20:40 2013
> @@ -3,7 +3,7 @@
>  ; Check that a fastcall function gets correct mangling
>
>  define x86_fastcallcc void @func(i64 %X, i8 %Y, i8 %G, i16 %Z) {
> -; CHECK: @func at 20:
> +; CHECK: "@func at 20":
>          ret void
>  }
>
>
> Modified: llvm/trunk/test/CodeGen/X86/stdcall.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/stdcall.ll?rev=192758&r1=192757&r2=192758&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/stdcall.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/stdcall.ll Tue Oct 15 20:20:40 2013
> @@ -5,7 +5,7 @@
>
>  define internal x86_stdcallcc void @MyFunc() nounwind {
>  entry:
> -; CHECK: MyFunc at 0:
> +; CHECK: "_MyFunc at 0":
>  ; CHECK: ret
>    ret void
>  }
> @@ -20,5 +20,5 @@ entry:
>
>  @B = global %0 { void (...)* bitcast (void ()* @MyFunc to void (...)*) }, align 4
>  ; CHECK: _B:
> -; CHECK: .long _MyFunc at 0
> +; CHECK: .long "_MyFunc at 0"
>
>
> Added: llvm/trunk/test/MC/COFF/quoted-names.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/COFF/quoted-names.ll?rev=192758&view=auto
> ==============================================================================
> --- llvm/trunk/test/MC/COFF/quoted-names.ll (added)
> +++ llvm/trunk/test/MC/COFF/quoted-names.ll Tue Oct 15 20:20:40 2013
> @@ -0,0 +1,20 @@
> +; Check that certain symbol and section names are quoted in the asm output.
> +; RUN: llc -mtriple=i686-pc-win32 %s -o - | FileCheck %s
> +
> +; Check that the symbol and section names can round-trip through the assembler.
> +; RUN: llc -mtriple=i686-pc-win32 %s -o - | llvm-mc -triple i686-pc-win32 -filetype=obj | llvm-readobj -s -section-symbols | FileCheck %s --check-prefix=READOBJ
> +
> +@"\01??__E_Generic_object@?$_Error_objects at H@std@@YAXXZ" = global i32 0
> +
> +define weak i32 @"\01??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51"() section ".text" {
> +  %res = load i32* @"\01??__E_Generic_object@?$_Error_objects at H@std@@YAXXZ"
> +  ret i32 %res
> +}
> +
> +; CHECK: .section ".text$??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51","xr"
> +; CHECK: .globl "??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51"
> +; CHECK: "??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51"
> +
> +; READOBJ: Symbol
> +; READOBJ: Name: ??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51
> +; READOBJ: Section: .text$??_B?$num_put at _WV?$back_insert_iterator at V?$basic_string at _WU?$char_traits at _W@std@@V?$allocator at _W@2@@std@@@std@@@std@@51
>
>
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