[llvm-commits] [llvm] r161477 - in /llvm/trunk: lib/MC/MCParser/DarwinAsmParser.cpp test/MC/MachO/previous.s test/MC/MachO/pushsection.s

[Rafael Espíndola]

This code is duplicated with the ELF asm parser. Do you intend to
refactor it? If not, would you mind opening a bug and assigning it to
me?

On 8 August 2012 02:30, Bill Wendling <isanbard at gmail.com> wrote:
> Author: void
> Date: Wed Aug  8 01:30:30 2012
> New Revision: 161477
>
> URL: http://llvm.org/viewvc/llvm-project?rev=161477&view=rev
> Log:
> Add `.pushsection', `.popsection', and `.previous' directives to Darwin ASM.
>
> There are situations where inline ASM may want to change the section -- for
> instance, to create a variable in the .data section. However, it cannot do this
> without (potentially) restoring to the wrong section. E.g.:
>
>   asm volatile (".section __DATA, __data\n\t"
>                 ".globl _fnord\n\t"
>                 "_fnord: .quad 1f\n\t"
>                 ".text\n\t"
>                 "1:" :::);
>
> This may be wrong if this is inlined into a function that has a "section"
> attribute. The user should use `.pushsection' and `.popsection' here instead.
>
> The addition of `.previous' is added for completeness.
> <rdar://problem/12048387>
>
> Added:
>     llvm/trunk/test/MC/MachO/previous.s
>     llvm/trunk/test/MC/MachO/pushsection.s
> Modified:
>     llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp
>
> Modified: llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp?rev=161477&r1=161476&r2=161477&view=diff
> ==============================================================================
> --- llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp (original)
> +++ llvm/trunk/lib/MC/MCParser/DarwinAsmParser.cpp Wed Aug  8 01:30:30 2012
> @@ -50,6 +50,9 @@
>      AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDumpOrLoad>(".dump");
>      AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveDumpOrLoad>(".load");
>      AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSection>(".section");
> +    AddDirectiveHandler<&DarwinAsmParser::ParseDirectivePushSection>(".pushsection");
> +    AddDirectiveHandler<&DarwinAsmParser::ParseDirectivePopSection>(".popsection");
> +    AddDirectiveHandler<&DarwinAsmParser::ParseDirectivePrevious>(".previous");
>      AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSecureLogUnique>(
>        ".secure_log_unique");
>      AddDirectiveHandler<&DarwinAsmParser::ParseDirectiveSecureLogReset>(
> @@ -112,6 +115,9 @@
>    bool ParseDirectiveDumpOrLoad(StringRef, SMLoc);
>    bool ParseDirectiveLsym(StringRef, SMLoc);
>    bool ParseDirectiveSection(StringRef, SMLoc);
> +  bool ParseDirectivePushSection(StringRef, SMLoc);
> +  bool ParseDirectivePopSection(StringRef, SMLoc);
> +  bool ParseDirectivePrevious(StringRef, SMLoc);
>    bool ParseDirectiveSecureLogReset(StringRef, SMLoc);
>    bool ParseDirectiveSecureLogUnique(StringRef, SMLoc);
>    bool ParseDirectiveSubsectionsViaSymbols(StringRef, SMLoc);
> @@ -297,7 +303,7 @@
>
>  };
>
> -}
> +} // end anonymous namespace
>
>  bool DarwinAsmParser::ParseSectionSwitch(const char *Segment,
>                                           const char *Section,
> @@ -457,6 +463,37 @@
>    return false;
>  }
>
> +/// ParseDirectivePushSection:
> +///   ::= .pushsection identifier (',' identifier)*
> +bool DarwinAsmParser::ParseDirectivePushSection(StringRef S, SMLoc Loc) {
> +  getStreamer().PushSection();
> +
> +  if (ParseDirectiveSection(S, Loc)) {
> +    getStreamer().PopSection();
> +    return true;
> +  }
> +
> +  return false;
> +}
> +
> +/// ParseDirectivePopSection:
> +///   ::= .popsection
> +bool DarwinAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
> +  if (!getStreamer().PopSection())
> +    return TokError(".popsection without corresponding .pushsection");
> +  return false;
> +}
> +
> +/// ParseDirectivePrevious:
> +///   ::= .previous
> +bool DarwinAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
> +  const MCSection *PreviousSection = getStreamer().getPreviousSection();
> +  if (PreviousSection == NULL)
> +      return TokError(".previous without corresponding .section");
> +  getStreamer().SwitchSection(PreviousSection);
> +  return false;
> +}
> +
>  /// ParseDirectiveSecureLogUnique
>  ///  ::= .secure_log_unique ... message ...
>  bool DarwinAsmParser::ParseDirectiveSecureLogUnique(StringRef, SMLoc IDLoc) {
> @@ -707,4 +744,4 @@
>    return new DarwinAsmParser;
>  }
>
> -}
> +} // end llvm namespace
>
> Added: llvm/trunk/test/MC/MachO/previous.s
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/previous.s?rev=161477&view=auto
> ==============================================================================
> --- llvm/trunk/test/MC/MachO/previous.s (added)
> +++ llvm/trunk/test/MC/MachO/previous.s Wed Aug  8 01:30:30 2012
> @@ -0,0 +1,13 @@
> +// RUN: llvm-mc -triple i386-apple-darwin9 %s -o - | FileCheck %s
> +
> +.text
> +// CHECK: .section __TEXT,__text
> +
> +.data
> +// CHECK: .section __DATA,__data
> +
> +.previous
> +// CHECK: .section __TEXT,__text
> +
> +.previous
> +// CHECK: .section __DATA,__data
>
> Added: llvm/trunk/test/MC/MachO/pushsection.s
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/pushsection.s?rev=161477&view=auto
> ==============================================================================
> --- llvm/trunk/test/MC/MachO/pushsection.s (added)
> +++ llvm/trunk/test/MC/MachO/pushsection.s Wed Aug  8 01:30:30 2012
> @@ -0,0 +1,16 @@
> +// RUN: llvm-mc -triple i386-apple-darwin9 %s -o - | FileCheck %s
> +
> +.text
> +// CHECK: .section __TEXT,__text
> +
> +.pushsection __DATA, __data
> +// CHECK: .section __DATA,__data
> +
> +.pushsection __TEXT, initcode
> +// CHECK: .section __TEXT,initcode
> +
> +.popsection
> +// CHECK: .section __DATA,__data
> +
> +.popsection
> +// CHECK: .section __TEXT,__text
>
>
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