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

[Eric Christopher]

On Fri, Mar 7, 2014 at 2:17 PM, David Blaikie <dblaikie at gmail.com> wrote:
> On Fri, Mar 7, 2014 at 2:09 PM, Adrian Prantl <aprantl at apple.com> wrote:
>> This was actually Greg's idea :-)
>> Ideally they would all be relative to the low_pc of the subprogram, I think.
>
> Yeah, I was discussing similar ideas with Eric yesterday too (I guess
> low_pc could be relative to the nearest enclosing low_pc (or at least
> just the subprogram - and even a subprogram's low_pc could, arguably,
> be relative to the CU's low_pc if it's using one))
>

*nod* Would seem to work for anything that doesn't need a set of
ranges for the compile unit. Vanishingly small for any language with
odr, but could be useful for C type stuff.

-eric

>>
>> -- adrian
>>
>> On Mar 7, 2014, at 14:08, David Blaikie <dblaikie at gmail.com> wrote:
>>
>>> On Fri, Mar 7, 2014 at 10:41 AM, Adrian Prantl <aprantl at apple.com> wrote:
>>>> Hi David,
>>>>
>>>> would it make sense to implement a similar change for high/low_pc of TAG_lexical_block, too?
>>>
>>> Oh... good point. I've done this for inlined subprograms in r203295
>>> since there was already a test case covering that (with a little
>>> improvement, anyway) - lexical blocks coming soon once I work up a
>>> test case.
>>>
>>>>
>>>> -- 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
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> llvm-commits mailing list
>>>>> llvm-commits at cs.uiuc.edu
>>>>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>>>
>>
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