r212263 - Move the calling of emitTargetMD() later.

Richard Smith richard at metafoo.co.uk
Fri Jul 18 18:21:27 PDT 2014


On Thu, Jul 17, 2014 at 1:47 AM, Robert Lytton <robert at xmos.com> wrote:

>  Hi Richard,
>
> Thank you for the review.
>
> I'll change the metadata numbers to use filecheck variables.
>
> In regard to using getMostRecentDecl, is the problem that I am using it
> too soon or the way I use it?
>

I think one problem is that getMostRecentDecl() is being called too late:
if this call is the only thing that causes us to pull in more declarations
from a module, and we decide those things need to be handed off to the
ASTConsumer, it cannot be called at the end of CodeGenModule finalization.
But something here doesn't make much sense: if we actually need to emit
those declarations, they should be pulled in regardless of your loop, and
if we don't, they shouldn't be causing CodeGen to do extra work.

Another issue this exposes is that CodeGen can trigger deserialization,
which can re-enter CodeGen in ways it's not expecting. That's bad
independent of your patch. The interaction between modules and CodeGen is
clearly not right, and I think it's not reasonable to block your work on
fixing it...

Indeed, if I was to add a pass, would it be needed at all - maybe the pass
> should handle multiple list entries of a symbol.
>
> I agree, building a target specific list and adding a pass seems good.
> Should I handle all global declarations in this way or only those I can't
> compute?
>

I think the best approach (for locality) is to immediately emit the
metadata in the common case where you can compute it, and to add it to a
list of delayed entities if you can't compute it.

I need to understand the best places to discover/add-to-list the global
> declarations.
> getTargetCodeGenInfo()::SetTargetAttributes only receives definitions (and
> their typestrings could be emitted).
> Is there another target hook which receives all declarations rather than
> only definitions?
>

You could add one, or perhaps change SetTargetAttributes so it's called on
declarations as well as definitions.


> I'll look through the code again regarding how 'MangledDeclNames' is
> built up to try to gain insight.
>
> Any guidance most welcome!
>
> Robert
>
>  ------------------------------
> *From:* metafoo at gmail.com [metafoo at gmail.com] on behalf of Richard Smith [
> richard at metafoo.co.uk]
> *Sent:* 16 July 2014 04:07
> *To:* Robert Lytton
> *Cc:* cfe commits
> *Subject:* Re: r212263 - Move the calling of emitTargetMD() later.
>
>    On Thu, Jul 3, 2014 at 2:30 AM, Robert Lytton <robert at xmos.com> wrote:
>
>> Author: rlytton
>> Date: Thu Jul  3 04:30:33 2014
>> New Revision: 212263
>>
>> URL: http://llvm.org/viewvc/llvm-project?rev=212263&view=rev
>> Log:
>> Move the calling of emitTargetMD() later.
>>
>> Summary:
>> Because a global created by GetOrCreateLLVMGlobal() is not finalised
>> until later viz:
>>   extern char a[];
>>   char f(){ return a[5];}
>>   char a[10];
>>
>> Change MangledDeclNames to use a MapVector rather than a DenseMap so that
>> the
>> Metadata is output in order of original declaration, so to make
>> deterministic
>> and improve human readablity.
>>
>
>  Sorry for not reviewing this before. I think this is completely the
> wrong approach. Please just keep a list of those variables for which you
> couldn't compute the type string when they are emitted (within
> XCoreTargetCodeGenInfo), and perform another pass at the end of IR
> generation to fix up those ones. That will have much better locality, and
> will avoid the target metadata emission loop that is redundant on almost
> all targets.
>
>  Differential Revision: http://reviews.llvm.org/D4176
>>
>> Modified:
>>     cfe/trunk/lib/CodeGen/CodeGenModule.cpp
>>     cfe/trunk/lib/CodeGen/CodeGenModule.h
>>     cfe/trunk/test/CodeGen/xcore-stringtype.c
>>
>> Modified: cfe/trunk/lib/CodeGen/CodeGenModule.cpp
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.cpp?rev=212263&r1=212262&r2=212263&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CodeGenModule.cpp (original)
>> +++ cfe/trunk/lib/CodeGen/CodeGenModule.cpp Thu Jul  3 04:30:33 2014
>> @@ -393,6 +393,8 @@ void CodeGenModule::Release() {
>>      DebugInfo->finalize();
>>
>>    EmitVersionIdentMetadata();
>> +
>> +  EmitTargetMetadata();
>>  }
>>
>>  void CodeGenModule::UpdateCompletedType(const TagDecl *TD) {
>> @@ -1534,8 +1536,6 @@ CodeGenModule::GetOrCreateLLVMFunction(S
>>      }
>>    }
>>
>> -  getTargetCodeGenInfo().emitTargetMD(D, F, *this);
>> -
>>    // Make sure the result is of the requested type.
>>    if (!IsIncompleteFunction) {
>>      assert(F->getType()->getElementType() == Ty);
>> @@ -1685,8 +1685,6 @@ CodeGenModule::GetOrCreateLLVMGlobal(Str
>>    if (AddrSpace != Ty->getAddressSpace())
>>      return llvm::ConstantExpr::getAddrSpaceCast(GV, Ty);
>>
>> -  getTargetCodeGenInfo().emitTargetMD(D, GV, *this);
>> -
>>    return GV;
>>  }
>>
>> @@ -3340,6 +3338,14 @@ void CodeGenModule::EmitVersionIdentMeta
>>    IdentMetadata->addOperand(llvm::MDNode::get(Ctx, IdentNode));
>>  }
>>
>> +void CodeGenModule::EmitTargetMetadata() {
>> +  for (auto &I : MangledDeclNames) {
>> +    const Decl *D = I.first.getDecl()->getMostRecentDecl();
>>
>
>  This has introduced an iterator invalidation bug that breaks most
> modules builds: getMostRecentDecl can result in lazy deserialization, and
> thus in MangledDeclNames having entries added to it.
>
>
>> +    llvm::GlobalValue *GV = GetGlobalValue(I.second);
>> +    getTargetCodeGenInfo().emitTargetMD(D, GV, *this);
>> +  }
>> +}
>> +
>>  void CodeGenModule::EmitCoverageFile() {
>>    if (!getCodeGenOpts().CoverageFile.empty()) {
>>      if (llvm::NamedMDNode *CUNode = TheModule.getNamedMetadata("
>> llvm.dbg.cu")) {
>>
>> Modified: cfe/trunk/lib/CodeGen/CodeGenModule.h
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenModule.h?rev=212263&r1=212262&r2=212263&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/lib/CodeGen/CodeGenModule.h (original)
>> +++ cfe/trunk/lib/CodeGen/CodeGenModule.h Thu Jul  3 04:30:33 2014
>> @@ -349,8 +349,8 @@ class CodeGenModule : public CodeGenType
>>    /// emitted when the translation unit is complete.
>>    CtorList GlobalDtors;
>>
>> -  /// A map of canonical GlobalDecls to their mangled names.
>> -  llvm::DenseMap<GlobalDecl, StringRef> MangledDeclNames;
>> +  /// An ordered map of canonical GlobalDecls to their mangled names.
>> +  llvm::MapVector<GlobalDecl, StringRef> MangledDeclNames;
>>    llvm::StringMap<GlobalDecl, llvm::BumpPtrAllocator> Manglings;
>>
>>    /// Global annotations.
>> @@ -1146,6 +1146,9 @@ private:
>>    /// \brief Emit the Clang version as llvm.ident metadata.
>>    void EmitVersionIdentMetadata();
>>
>> +  /// Emits target specific Metadata for global declarations.
>> +  void EmitTargetMetadata();
>> +
>>    /// Emit the llvm.gcov metadata used to tell LLVM where to emit the
>> .gcno and
>>    /// .gcda files in a way that persists in .bc files.
>>    void EmitCoverageFile();
>>
>> Modified: cfe/trunk/test/CodeGen/xcore-stringtype.c
>> URL:
>> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/xcore-stringtype.c?rev=212263&r1=212262&r2=212263&view=diff
>>
>> ==============================================================================
>> --- cfe/trunk/test/CodeGen/xcore-stringtype.c (original)
>> +++ cfe/trunk/test/CodeGen/xcore-stringtype.c Thu Jul  3 04:30:33 2014
>> @@ -9,13 +9,13 @@
>>  // Please see 'Tools Development Guide' section 2.16.2 for format
>> details:
>>  // <
>> https://www.xmos.com/download/public/Tools-Development-Guide%28X9114A%29.pdf
>> >
>>
>> -// CHECK: !xcore.typestrings = !{!0, !1, !2, !3, !4, !5, !6, !7, !8, !9,
>> !10,
>> -// CHECK: !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22,
>> !23,
>> -// CHECK: !24, !25, !26, !27, !28, !29, !30, !31, !32, !33, !34}
>> +// CHECK: !xcore.typestrings = !{!1, !2, !3, !4, !5, !6, !7, !8, !9,
>> !10, !11,
>> +// CHECK: !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23,
>> !24, !25,
>> +// CHECK: !26, !27, !28, !29, !30, !31, !32, !33, !34, !35, !36, !37,
>> !38}
>>
>
>  Please fix this test to not hardcode metadata numbers; these are
> extremely fragile, and will break if we start emitting more metadata for
> any reason. Instead, use FileCheck variables (
> http://llvm.org/docs/CommandGuide/FileCheck.html#filecheck-variables).
>
>
>>  // test BuiltinType
>> -// CHECK: !0 = metadata !{void (i1, i8, i8, i8, i16, i16, i16, i32, i32,
>> i32,
>> +// CHECK: !1 = metadata !{void (i1, i8, i8, i8, i16, i16, i16, i32, i32,
>> i32,
>>  // CHECK:      i32, i32, i32, i64, i64, i64, float, double, double)*
>>  // CHECK:      @builtinType, metadata
>> !"f{0}(b,uc,uc,sc,ss,us,ss,si,ui,si,sl,
>>  // CHECK:      ul,sl,sll,ull,sll,ft,d,ld)"}
>> @@ -28,14 +28,14 @@ double _Complex Complex; // not supporte
>>
>>
>>  // test FunctionType & Qualifiers
>> -// CHECK: !1 = metadata !{void ()* @gI, metadata !"f{0}()"}
>> -// CHECK: !2 = metadata !{void (...)* @eI, metadata !"f{0}()"}
>> -// CHECK: !3 = metadata !{void ()* @gV, metadata !"f{0}(0)"}
>> -// CHECK: !4 = metadata !{void ()* @eV, metadata !"f{0}(0)"}
>> -// CHECK: !5 = metadata !{void (i32, ...)* @gVA, metadata !"f{0}(si,va)"}
>> -// CHECK: !6 = metadata !{void (i32, ...)* @eVA, metadata !"f{0}(si,va)"}
>> -// CHECK: !7 = metadata !{i32* (i32*)* @gQ, metadata
>> !"f{crv:p(cv:si)}(p(cv:si))"}
>> -// CHECK: !8 = metadata !{i32* (i32*)* @eQ, metadata
>> !"f{crv:p(cv:si)}(p(cv:si))"}
>> +// CHECK: !2 = metadata !{void ()* @gI, metadata !"f{0}()"}
>> +// CHECK: !3 = metadata !{void (...)* @eI, metadata !"f{0}()"}
>> +// CHECK: !4 = metadata !{void ()* @gV, metadata !"f{0}(0)"}
>> +// CHECK: !5 = metadata !{void ()* @eV, metadata !"f{0}(0)"}
>> +// CHECK: !6 = metadata !{void (i32, ...)* @gVA, metadata !"f{0}(si,va)"}
>> +// CHECK: !7 = metadata !{void (i32, ...)* @eVA, metadata !"f{0}(si,va)"}
>> +// CHECK: !8 = metadata !{i32* (i32*)* @gQ, metadata
>> !"f{crv:p(cv:si)}(p(cv:si))"}
>> +// CHECK: !9 = metadata !{i32* (i32*)* @eQ, metadata
>> !"f{crv:p(cv:si)}(p(cv:si))"}
>>  extern void eI();
>>  void gI() {eI();};
>>  extern void eV(void);
>> @@ -49,10 +49,10 @@ const volatile int* volatile restrict co
>>
>>
>>  // test PointerType
>> -// CHECK: !9 = metadata !{i32* (i32*, i32* (i32*)*)*
>> -// CHECK:      @pointerType, metadata
>> !"f{p(si)}(p(si),p(f{p(si)}(p(si))))"}
>> -// CHECK: !10 = metadata !{i32** @EP, metadata !"p(si)"}
>> -// CHECK: !11 = metadata !{i32** @GP, metadata !"p(si)"}
>> +// CHECK: !10 = metadata !{i32* (i32*, i32* (i32*)*)*
>> +// CHECK:       @pointerType, metadata
>> !"f{p(si)}(p(si),p(f{p(si)}(p(si))))"}
>> +// CHECK: !11 = metadata !{i32** @EP, metadata !"p(si)"}
>> +// CHECK: !12 = metadata !{i32** @GP, metadata !"p(si)"}
>>  extern int* EP;
>>  int* GP;
>>  int* pointerType(int *I, int * (*FP)(int *)) {
>> @@ -60,25 +60,25 @@ int* pointerType(int *I, int * (*FP)(int
>>  }
>>
>>  // test ArrayType
>> -// CHECK: !12 = metadata !{[2 x i32]* (i32*, i32*, [2 x i32]*, [2 x
>> i32]*, i32*)*
>> +// CHECK: !13 = metadata !{[2 x i32]* (i32*, i32*, [2 x i32]*, [2 x
>> i32]*, i32*)*
>>  // CHECK:       @arrayType, metadata
>> !"f{p(a(2:si))}(p(si),p(cv:si),p(a(2:si)),
>>  // CHECK:       p(a(2:si)),p(si))"}
>> -// CHECK: !13 = metadata !{[0 x i32]* @EA1, metadata !"a(*:cv:si)"}
>> -// CHECK: !14 = metadata !{[2 x i32]* @EA2, metadata !"a(2:si)"}
>> -// CHECK: !15 = metadata !{[0 x [2 x i32]]* @EA3, metadata
>> !"a(*:a(2:si))"}
>> -// CHECK: !16 = metadata !{[3 x [2 x i32]]* @EA4, metadata
>> !"a(3:a(2:si))"}
>> -// CHECK: !17 = metadata !{[2 x i32]* @GA1, metadata !"a(2:cv:si)"}
>> -// CHECK: !18 = metadata !{void ([2 x i32]*)* @arrayTypeVariable1,
>> +// CHECK: !14 = metadata !{[0 x i32]* @EA1, metadata !"a(*:cv:si)"}
>> +// CHECK: !15 = metadata !{[2 x i32]* @EA2, metadata !"a(2:si)"}
>> +// CHECK: !16 = metadata !{[0 x [2 x i32]]* @EA3, metadata
>> !"a(*:a(2:si))"}
>> +// CHECK: !17 = metadata !{[3 x [2 x i32]]* @EA4, metadata
>> !"a(3:a(2:si))"}
>> +// CHECK: !18 = metadata !{[2 x i32]* @GA1, metadata !"a(2:cv:si)"}
>> +// CHECK: !19 = metadata !{void ([2 x i32]*)* @arrayTypeVariable1,
>>  // CHECK:       metadata !"f{0}(p(a(2:si)))"}
>> -// CHECK: !19 = metadata !{void (void ([2 x i32]*)*)*
>> @arrayTypeVariable2,
>> +// CHECK: !20 = metadata !{void (void ([2 x i32]*)*)*
>> @arrayTypeVariable2,
>>  // CHECK:       metadata !"f{0}(p(f{0}(p(a(2:si)))))"}
>> -// CHECK: !20 = metadata !{[3 x [2 x i32]]* @GA2, metadata
>> !"a(3:a(2:si))"}
>> +// CHECK: !21 = metadata !{[3 x [2 x i32]]* @GA2, metadata
>> !"a(3:a(2:si))"}
>> +extern int GA2[3][2];
>>  extern const volatile int EA1[];
>>  extern int EA2[2];
>>  extern int EA3[][2];
>>  extern int EA4[3][2];
>>  const volatile int GA1[2];
>> -int GA2[3][2];
>>  extern void arrayTypeVariable1(int[*][2]);
>>  extern void arrayTypeVariable2( void(*fp)(int[*][2]) );
>>  extern void arrayTypeVariable3(int[3][*]);                // not
>> supported
>> @@ -100,16 +100,16 @@ RetType* arrayType(int A1[], int const v
>>
>>
>>  // test StructureType
>> -// CHECK: !21 = metadata !{void (%struct.S1*)* @structureType1, metadata
>> +// CHECK: !22 = metadata !{void (%struct.S1*)* @structureType1, metadata
>>  // CHECK:
>> !"f{0}(s(S1){m(ps2){p(s(S2){m(ps3){p(s(S3){m(s1){s(S1){}}})}})}})"}
>> -// CHECK: !22 = metadata !{void (%struct.S2*)* @structureType2, metadata
>> +// CHECK: !23 = metadata !{void (%struct.S2*)* @structureType2, metadata
>>  // CHECK:
>> !"f{0}(s(S2){m(ps3){p(s(S3){m(s1){s(S1){m(ps2){p(s(S2){})}}}})}})"}
>> -// CHECK: !23 = metadata !{void (%struct.S3*)* @structureType3, metadata
>> +// CHECK: !24 = metadata !{void (%struct.S3*)* @structureType3, metadata
>>  // CHECK:
>> !"f{0}(s(S3){m(s1){s(S1){m(ps2){p(s(S2){m(ps3){p(s(S3){})}})}}}})"}
>> -// CHECK: !24 = metadata !{void (%struct.S4*)* @structureType4, metadata
>> +// CHECK: !25 = metadata !{void (%struct.S4*)* @structureType4, metadata
>>  // CHECK:
>> !"f{0}(s(S4){m(s1){s(S1){m(ps2){p(s(S2){m(ps3){p(s(S3){m(s1){s(S1){}}})}})}}}})"}
>> -// CHECK: !25 = metadata !{%struct.anon* @StructAnon, metadata
>> !"s(){m(A){si}}"}
>> -// CHECK: !26 = metadata !{i32 (%struct.SB*)* @structureTypeB, metadata
>> +// CHECK: !26 = metadata !{%struct.anon* @StructAnon, metadata
>> !"s(){m(A){si}}"}
>> +// CHECK: !27 = metadata !{i32 (%struct.SB*)* @structureTypeB, metadata
>>  // CHECK:       !"f{si}(s(SB){m(){b(4:si)},m(){b(2:si)},m(N4){b(4:si)},
>>  // CHECK:       m(N2){b(2:si)},m(){b(4:ui)},m(){b(4:si)},m(){b(4:c:si)},
>>  // CHECK:       m(){b(4:c:si)},m(){b(4:cv:si)}})"}
>> @@ -130,16 +130,16 @@ int structureTypeB(struct SB sb){return
>>
>>
>>  // test UnionType
>> -// CHECK: !27 = metadata !{void (%union.U1*)* @unionType1, metadata
>> +// CHECK: !28 = metadata !{void (%union.U1*)* @unionType1, metadata
>>  // CHECK:
>> !"f{0}(u(U1){m(pu2){p(u(U2){m(pu3){p(u(U3){m(u1){u(U1){}}})}})}})"}
>> -// CHECK: !28 = metadata !{void (%union.U2*)* @unionType2, metadata
>> +// CHECK: !29 = metadata !{void (%union.U2*)* @unionType2, metadata
>>  // CHECK:
>> !"f{0}(u(U2){m(pu3){p(u(U3){m(u1){u(U1){m(pu2){p(u(U2){})}}}})}})"}
>> -// CHECK: !29 = metadata !{void (%union.U3*)* @unionType3, metadata
>> +// CHECK: !30 = metadata !{void (%union.U3*)* @unionType3, metadata
>>  // CHECK:
>> !"f{0}(u(U3){m(u1){u(U1){m(pu2){p(u(U2){m(pu3){p(u(U3){})}})}}}})"}
>> -// CHECK: !30 = metadata !{void (%union.U4*)* @unionType4, metadata
>> +// CHECK: !31 = metadata !{void (%union.U4*)* @unionType4, metadata
>>  // CHECK:
>> !"f{0}(u(U4){m(u1){u(U1){m(pu2){p(u(U2){m(pu3){p(u(U3){m(u1){u(U1){}}})}})}}}})"}
>> -// CHECK: !31 = metadata !{%union.anon* @UnionAnon, metadata
>> !"u(){m(A){si}}"}
>> -// CHECK: !32 = metadata !{i32 (%union.UB*)* @unionTypeB, metadata
>> +// CHECK: !32 = metadata !{%union.anon* @UnionAnon, metadata
>> !"u(){m(A){si}}"}
>> +// CHECK: !33 = metadata !{i32 (%union.UB*)* @unionTypeB, metadata
>>  // CHECK:       !"f{si}(u(UB){m(N2){b(2:si)},m(N4){b(4:si)},m(){b(2:si)},
>>  // CHECK:
>> m(){b(4:c:si)},m(){b(4:c:si)},m(){b(4:cv:si)},m(){b(4:si)},
>>  // CHECK:       m(){b(4:si)},m(){b(4:ui)}})"}
>> @@ -160,9 +160,20 @@ int unionTypeB(union UB ub) {return Unio
>>
>>
>>  // test EnumType
>> -// CHECK: !33 = metadata !{i32* @EnumAnon, metadata !"e(){m(EA){3}}"}
>> -// CHECK: !34 = metadata !{i32 (i32)* @enumType, metadata
>> +// CHECK: !34 = metadata !{i32* @EnumAnon, metadata !"e(){m(EA){3}}"}
>> +// CHECK: !35 = metadata !{i32 (i32)* @enumType, metadata
>>  // CHECK:       !"f{si}(e(E){m(A){7},m(B){6},m(C){5},m(D){0}})"}
>>  enum E {D, C=5, B, A};
>>  enum {EA=3} EnumAnon = EA;
>>  int enumType(enum E e) {return EnumAnon;}
>> +
>> +
>> +// CHECK: !36 = metadata !{i32 ()* @testReDecl, metadata !"f{si}()"}
>> +// CHECK: !37 = metadata !{[10 x i32]* @After, metadata !"a(10:si)"}
>> +// CHECK: !38 = metadata !{[10 x i32]* @Before, metadata !"a(10:si)"}
>> +extern int After[];
>> +extern int Before[10];
>> +int testReDecl() {return After[0] + Before[0];}
>> +int After[10];
>> +int Before[];
>> +
>>
>>
>> _______________________________________________
>> cfe-commits mailing list
>> cfe-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>>
>
>
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