r195495 - Debug Info: add a "Debug Info Version" module flag to output the current debug

[Manman Ren]

On Fri, Nov 22, 2013 at 1:34 PM, David Blaikie <dblaikie at gmail.com> wrote:

>
>
>
> On Fri, Nov 22, 2013 at 12:07 PM, Manman Ren <manman.ren at gmail.com> wrote:
>
>>
>>
>>
>> On Fri, Nov 22, 2013 at 11:59 AM, Eric Christopher <echristo at gmail.com>wrote:
>>
>>> On Fri, Nov 22, 2013 at 11:42 AM, Manman Ren <manman.ren at gmail.com>
>>> wrote:
>>> > Author: mren
>>> > Date: Fri Nov 22 13:42:45 2013
>>> > New Revision: 195495
>>> >
>>> > URL: http://llvm.org/viewvc/llvm-project?rev=195495&view=rev
>>> > Log:
>>> > Debug Info: add a "Debug Info Version" module flag to output the
>>> current debug
>>> > info version number.
>>> >
>>> > Will error out when modules have different version numbers.
>>> >
>>>
>>> I don't think the commit message or comment are correct. We're going
>>> to strip debug info at module merge time if they have different
>>> versions, not error out at merge time.
>>>
>>
>> The commit message and the comment is for what is implemented in the
>> patch. The module flag will be used to strip debug info later on.
>>  And I plan to talk about stripping debug info when the patch that
>> actually strips debug info is committed.
>> The comment tries to explain why we choose the error mode and what will
>> happen if the linker sees different versions.
>>
>> Should we talk about how the module flag will be used when adding the
>> module flag in the source code?
>> Maybe if we want to be verbose.
>>
>
> It's not uncommon to do that - providing a comment about where this work
> fits in the grand scheme of things either in the source or the commit
> message, or both.
>

Makes sense. I will expand my comments.

Manman


>
>
> - David
>
>
>>
>> Manman
>>
>>
>>>
>>> -eric
>>>
>>> > Added:
>>> >     cfe/trunk/test/CodeGen/debug-info-version.c
>>> > Modified:
>>> >     cfe/trunk/lib/CodeGen/CodeGenModule.cpp
>>> >
>>> > Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=195495&r1=195494&r2=195495&view=diff
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
>>> > +++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Fri Nov 22 13:42:45 2013
>>> > @@ -258,6 +258,11 @@ void CodeGenModule::Release() {
>>> >      // We can change from Warning to Latest if such mode is supported.
>>> >      getModule().addModuleFlag(llvm::Module::Warning, "Dwarf Version",
>>> >                                CodeGenOpts.DwarfVersion);
>>> > +  if (DebugInfo)
>>> > +    // We support a single version in the linked module: error out
>>> when
>>> > +    // modules do not have the same version.
>>> > +    getModule().addModuleFlag(llvm::Module::Error, "Debug Info
>>> Version",
>>> > +                              llvm::dwarf::DEBUG_INFO_VERSION);
>>> >
>>> >    SimplifyPersonality();
>>> >
>>> >
>>> > Added: cfe/trunk/test/CodeGen/debug-info-version.c
>>> > URL:
>>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/debug-info-version.c?rev=195495&view=auto
>>> >
>>> ==============================================================================
>>> > --- cfe/trunk/test/CodeGen/debug-info-version.c (added)
>>> > +++ cfe/trunk/test/CodeGen/debug-info-version.c Fri Nov 22 13:42:45
>>> 2013
>>> > @@ -0,0 +1,8 @@
>>> > +// RUN: %clang -g -S -emit-llvm -o - %s | FileCheck %s
>>> > +// RUN: %clang -S -emit-llvm -o - %s | FileCheck %s
>>> --check-prefix=NO_DEBUG
>>> > +int main (void) {
>>> > +  return 0;
>>> > +}
>>> > +
>>> > +// CHECK: metadata !{i32 1, metadata !"Debug Info Version", i32 1}
>>> > +// NO_DEBUG-NOT: metadata !"Debug Info Version"
>>> >
>>> >
>>> > _______________________________________________
>>> > cfe-commits mailing list
>>> > cfe-commits at cs.uiuc.edu
>>> > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>>
>>
>>
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>
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