[llvm] r203187 - DebugInfo: Emit DW_TAG_subprogram's DW_AT_high_pc as an offset from the low_pc

[Adrian Prantl]

Hi David,

would it make sense to implement a similar change for high/low_pc of TAG_lexical_block, too?

-- adrian


On Mar 6, 2014, at 17:30, David Blaikie <dblaikie at gmail.com> wrote:

> Author: dblaikie
> Date: Thu Mar  6 19:30:55 2014
> New Revision: 203187
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=203187&view=rev
> Log:
> DebugInfo: Emit DW_TAG_subprogram's DW_AT_high_pc as an offset from the low_pc
> 
> This removes a relocation from each subprogram, reducing link times,
> etc.
> 
> Modified:
>    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
>    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
>    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
>    llvm/trunk/test/DebugInfo/AArch64/dwarfdump.ll
>    llvm/trunk/test/DebugInfo/X86/dbg-value-location.ll
> 
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=203187&r1=203186&r2=203187&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Thu Mar  6 19:30:55 2014
> @@ -413,7 +413,8 @@ DIE *DwarfDebug::updateSubprogramScopeDI
>   }
> 
>   SPCU->addLabelAddress(SPDie, dwarf::DW_AT_low_pc, FunctionBeginSym);
> -  SPCU->addLabelAddress(SPDie, dwarf::DW_AT_high_pc, FunctionEndSym);
> +  SPCU->addLabelDelta(SPDie, dwarf::DW_AT_high_pc, FunctionEndSym,
> +                      FunctionBeginSym);
> 
>   const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
>   MachineLocation Location(RI->getFrameRegister(*Asm->MF));
> 
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=203187&r1=203186&r2=203187&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Thu Mar  6 19:30:55 2014
> @@ -320,6 +320,12 @@ void DwarfUnit::addSectionDelta(DIE *Die
>     Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
> }
> 
> +void DwarfUnit::addLabelDelta(DIE *Die, dwarf::Attribute Attribute,
> +                              const MCSymbol *Hi, const MCSymbol *Lo) {
> +  DIEValue *Value = new (DIEValueAllocator) DIEDelta(Hi, Lo);
> +  Die->addValue(Attribute, dwarf::DW_FORM_data4, Value);
> +}
> +
> /// addDIEEntry - Add a DIE attribute data and value.
> ///
> void DwarfUnit::addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry) {
> 
> Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h?rev=203187&r1=203186&r2=203187&view=diff
> ==============================================================================
> --- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h (original)
> +++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h Thu Mar  6 19:30:55 2014
> @@ -359,6 +359,10 @@ public:
>   void addSectionDelta(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
>                        const MCSymbol *Lo);
> 
> +  /// addLabelDelta - Add a label delta attribute data and value.
> +  void addLabelDelta(DIE *Die, dwarf::Attribute Attribute, const MCSymbol *Hi,
> +                     const MCSymbol *Lo);
> +
>   /// addDIEEntry - Add a DIE attribute data and value.
>   void addDIEEntry(DIE *Die, dwarf::Attribute Attribute, DIE *Entry);
> 
> 
> Modified: llvm/trunk/test/DebugInfo/AArch64/dwarfdump.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/AArch64/dwarfdump.ll?rev=203187&r1=203186&r2=203187&view=diff
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/AArch64/dwarfdump.ll (original)
> +++ llvm/trunk/test/DebugInfo/AArch64/dwarfdump.ll Thu Mar  6 19:30:55 2014
> @@ -12,7 +12,7 @@
> ; A couple of ABS64s similarly:
> 
> ; CHECK: DW_AT_low_pc [DW_FORM_addr] (0x0000000000000000)
> -; CHECK: DW_AT_high_pc [DW_FORM_addr] (0x0000000000000008)
> +; CHECK: DW_AT_high_pc [DW_FORM_data4] (0x00000008)
> 
> define i32 @main() nounwind {
>   ret i32 0, !dbg !8
> 
> Modified: llvm/trunk/test/DebugInfo/X86/dbg-value-location.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/dbg-value-location.ll?rev=203187&r1=203186&r2=203187&view=diff
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/X86/dbg-value-location.ll (original)
> +++ llvm/trunk/test/DebugInfo/X86/dbg-value-location.ll Thu Mar  6 19:30:55 2014
> @@ -4,7 +4,7 @@ target datalayout = "e-p:64:64:64-i1:8:8
> target triple = "x86_64-apple-darwin10.0.0"
> ;Radar 8950491
> 
> -;CHECK: .long Lset5
> +;CHECK: .long Lset6
> ;CHECK-NEXT:        ## DW_AT_decl_file
> ;CHECK-NEXT:        ## DW_AT_decl_line
> ;CHECK-NEXT:        ## DW_AT_type
> 
> 
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