[PATCH] Record the DWARF version in MCContext

[David Blaikie]

You can use a common prefix for multiple FileChecks like this:

FileCheck --check-prefix=ASM --check-prefix=V2
FileCheck --check-prefix=ASM --check-prefix=V3

ASM: stuff
V2: byte 2
V3: byte 3
ASM: stuff

Which makes the test a bit simpler to read by removing duplication.

On Wed, Apr 16, 2014 at 9:16 AM, Oliver Stannard
<oliver.stannard at arm.com> wrote:
>   Expand test/MC/ELF/gen-dwarf.s to check that the correct dwarf version is emitted.
>
> http://reviews.llvm.org/D3399
>
> CHANGE SINCE LAST DIFF
>   http://reviews.llvm.org/D3399?vs=8569&id=8577#toc
>
> Files:
>   include/llvm/MC/MCContext.h
>   lib/MC/MCDwarf.cpp
>   test/MC/ELF/gen-dwarf.s
>   tools/llvm-mc/llvm-mc.cpp
>
> Index: include/llvm/MC/MCContext.h
> ===================================================================
> --- include/llvm/MC/MCContext.h
> +++ include/llvm/MC/MCContext.h
> @@ -147,6 +147,9 @@
>      /// non-empty.
>      StringRef DwarfDebugProducer;
>
> +    /// The maximum version of dwarf that we should emit.
> +    unsigned DwarfVersion;
> +
>      /// Honor temporary labels, this is useful for debugging semantic
>      /// differences between temporary and non-temporary labels (primarily on
>      /// Darwin).
> @@ -396,6 +399,9 @@
>      void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; }
>      StringRef getDwarfDebugProducer() { return DwarfDebugProducer; }
>
> +    void setDwarfVersion(unsigned v) { DwarfVersion = v; }
> +    unsigned getDwarfVersion() const { return DwarfVersion; }
> +
>      /// @}
>
>      char *getSecureLogFile() { return SecureLogFile; }
> Index: lib/MC/MCDwarf.cpp
> ===================================================================
> --- lib/MC/MCDwarf.cpp
> +++ lib/MC/MCDwarf.cpp
> @@ -645,8 +645,8 @@
>    const MCExpr *Length = MakeStartMinusEndExpr(*MCOS, *InfoStart, *InfoEnd, 4);
>    MCOS->EmitAbsValue(Length, 4);
>
> -  // The 2 byte DWARF version, which is 2.
> -  MCOS->EmitIntValue(2, 2);
> +  // The 2 byte DWARF version.
> +  MCOS->EmitIntValue(context.getDwarfVersion(), 2);
>
>    // The 4 byte offset to the debug abbrevs from the start of the .debug_abbrev,
>    // it is at the start of that section so this is zero.
> Index: test/MC/ELF/gen-dwarf.s
> ===================================================================
> --- test/MC/ELF/gen-dwarf.s
> +++ test/MC/ELF/gen-dwarf.s
> @@ -1,5 +1,7 @@
> -// RUN: llvm-mc -g -triple  i686-pc-linux-gnu %s -filetype=obj -o - | llvm-readobj -r | FileCheck %s
> +// RUN: llvm-mc -g -dwarf-version 2 -triple  i686-pc-linux-gnu %s -filetype=obj -o - | llvm-readobj -r | FileCheck %s
>  // RUN: llvm-mc -g -triple  i686-pc-linux-gnu %s -filetype=asm -o - | FileCheck --check-prefix=ASM %s
> +// RUN: llvm-mc -g -dwarf-version 2 -triple  i686-pc-linux-gnu %s -filetype=asm -o - | FileCheck --check-prefix=ASM2 %s
> +// RUN: llvm-mc -g -dwarf-version 3 -triple  i686-pc-linux-gnu %s -filetype=asm -o - | FileCheck --check-prefix=ASM3 %s
>
>
>  // Test that on ELF:
> @@ -34,8 +36,12 @@
>
>  // Second instance of the section has the CU
>  // ASM: .section .debug_info
> +// ASM2: .section .debug_info
> +// ASM3: .section .debug_info
>  // Dwarf version
> -// ASM: .short 2
> +// ASM2: .short 2
> +// ASM3: .short 3
> +// ASM: .short 4
>  // ASM-NEXT: .long [[ABBREV_LABEL]]
>  // First .byte 1 is the abbreviation number for the compile_unit abbrev
>  // ASM: .byte 1
> Index: tools/llvm-mc/llvm-mc.cpp
> ===================================================================
> --- tools/llvm-mc/llvm-mc.cpp
> +++ tools/llvm-mc/llvm-mc.cpp
> @@ -153,6 +153,9 @@
>  GenDwarfForAssembly("g", cl::desc("Generate dwarf debugging info for assembly "
>                                    "source files"));
>
> +static cl::opt<int>
> +DwarfVersion("dwarf-version", cl::desc("Dwarf version"), cl::init(4));
> +
>  static cl::opt<std::string>
>  DebugCompilationDir("fdebug-compilation-dir",
>                      cl::desc("Specifies the debug info's compilation dir"));
> @@ -403,6 +406,12 @@
>      Ctx.setAllowTemporaryLabels(false);
>
>    Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
> +  if (DwarfVersion < 2 || DwarfVersion > 4) {
> +    errs() << ProgName << ": Dwarf version " << DwarfVersion
> +           << " is not supported." << '\n';
> +    return 1;
> +  }
> +  Ctx.setDwarfVersion(DwarfVersion);
>    if (!DwarfDebugFlags.empty())
>      Ctx.setDwarfDebugFlags(StringRef(DwarfDebugFlags));
>    if (!DwarfDebugProducer.empty())