r186262 - PR16214, PR14467: DebugInfo: use "RequireCompleteType" to decide when to emit the full definition of a type in -flimit-debug-info

Richard Smith richard at metafoo.co.uk
Sat Jul 13 15:21:08 PDT 2013


On Sat, Jul 13, 2013 at 2:08 PM, David Blaikie <dblaikie at gmail.com> wrote:
> Author: dblaikie
> Date: Sat Jul 13 16:08:14 2013
> New Revision: 186262
>
> URL: http://llvm.org/viewvc/llvm-project?rev=186262&view=rev
> Log:
> PR16214, PR14467: DebugInfo: use "RequireCompleteType" to decide when to emit the full definition of a type in -flimit-debug-info
>
> This simplifies the core benefit of -flimit-debug-info by taking a more
> systematic approach to avoid emitting debug info definitions for types
> that only require declarations. The previous ad-hoc approach (3 cases
> removed in this patch) had many holes.
>
> The general approach (adding a bit to TagDecl and callback through
> ASTConsumer) has been discussed with Richard Smith - though always open
> to revision.
>
> Modified:
>     cfe/trunk/include/clang/AST/ASTConsumer.h
>     cfe/trunk/include/clang/AST/Decl.h
>     cfe/trunk/include/clang/Sema/Sema.h
>     cfe/trunk/lib/CodeGen/CGClass.cpp
>     cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
>     cfe/trunk/lib/CodeGen/CGExprCXX.cpp
>     cfe/trunk/lib/CodeGen/CGExprScalar.cpp
>     cfe/trunk/lib/CodeGen/CodeGenAction.cpp
>     cfe/trunk/lib/CodeGen/ModuleBuilder.cpp
>     cfe/trunk/lib/Sema/SemaType.cpp
>     cfe/trunk/test/CodeGenCXX/debug-info-class-limited.cpp
>
> Modified: cfe/trunk/include/clang/AST/ASTConsumer.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/ASTConsumer.h?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/ASTConsumer.h (original)
> +++ cfe/trunk/include/clang/AST/ASTConsumer.h Sat Jul 13 16:08:14 2013
> @@ -72,6 +72,10 @@ public:
>    /// can be defined in declspecs).
>    virtual void HandleTagDeclDefinition(TagDecl *D) {}
>
> +  /// \brief This callback is invoked the first time each TagDecl is required to
> +  /// be complete.
> +  virtual void HandleTagDeclRequiredDefinition(const TagDecl *D) {}
> +
>    /// \brief Invoked when a function is implicitly instantiated.
>    /// Note that at this point point it does not have a body, its body is
>    /// instantiated at the end of the translation unit and passed to
>
> Modified: cfe/trunk/include/clang/AST/Decl.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/AST/Decl.h?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/AST/Decl.h (original)
> +++ cfe/trunk/include/clang/AST/Decl.h Sat Jul 13 16:08:14 2013
> @@ -2445,6 +2445,9 @@ protected:
>    /// This option is only enabled when modules are enabled.
>    bool MayHaveOutOfDateDef : 1;
>
> +  /// Has the full definition of this type been required by a use somewhere in
> +  /// the TU.
> +  bool IsCompleteDefinitionRequired : 1;

It looks like you're missing serialization/deserialization support for
this flag.

>  private:
>    SourceLocation RBraceLoc;
>
> @@ -2531,6 +2534,12 @@ public:
>      return IsCompleteDefinition;
>    }
>
> +  /// \brief Return true if this complete decl is
> +  /// required to be complete for some existing use.
> +  bool isCompleteDefinitionRequired() const {
> +    return IsCompleteDefinitionRequired;
> +  }
> +
>    /// isBeingDefined - Return true if this decl is currently being defined.
>    bool isBeingDefined() const {
>      return IsBeingDefined;
> @@ -2572,6 +2581,8 @@ public:
>
>    void setCompleteDefinition(bool V) { IsCompleteDefinition = V; }
>
> +  void setCompleteDefinitionRequired() { IsCompleteDefinitionRequired = true; }
> +
>    // FIXME: Return StringRef;
>    const char *getKindName() const {
>      return TypeWithKeyword::getTagTypeKindName(getTagKind());
>
> Modified: cfe/trunk/include/clang/Sema/Sema.h
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/include/clang/Sema/Sema.h (original)
> +++ cfe/trunk/include/clang/Sema/Sema.h Sat Jul 13 16:08:14 2013
> @@ -1182,6 +1182,10 @@ public:
>      virtual ~BoundTypeDiagnoser3() { }
>    };
>
> +private:
> +  bool RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
> +                           TypeDiagnoser &Diagnoser);
> +public:
>    bool RequireCompleteType(SourceLocation Loc, QualType T,
>                             TypeDiagnoser &Diagnoser);
>    bool RequireCompleteType(SourceLocation Loc, QualType T,
>
> Modified: cfe/trunk/lib/CodeGen/CGClass.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGClass.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGClass.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGClass.cpp Sat Jul 13 16:08:14 2013
> @@ -1630,17 +1630,6 @@ CodeGenFunction::EmitCXXConstructorCall(
>                                          llvm::Value *This,
>                                          CallExpr::const_arg_iterator ArgBeg,
>                                          CallExpr::const_arg_iterator ArgEnd) {
> -
> -  CGDebugInfo *DI = getDebugInfo();
> -  if (DI &&
> -      CGM.getCodeGenOpts().getDebugInfo() == CodeGenOptions::LimitedDebugInfo) {
> -    // If debug info for this class has not been emitted then this is the
> -    // right time to do so.
> -    const CXXRecordDecl *Parent = D->getParent();
> -    DI->getOrCreateRecordType(CGM.getContext().getTypeDeclType(Parent),
> -                              Parent->getLocation());
> -  }
> -
>    // If this is a trivial constructor, just emit what's needed.
>    if (D->isTrivial()) {
>      if (ArgBeg == ArgEnd) {
>
> Modified: cfe/trunk/lib/CodeGen/CGDebugInfo.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGDebugInfo.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGDebugInfo.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGDebugInfo.cpp Sat Jul 13 16:08:14 2013
> @@ -1379,7 +1379,8 @@ llvm::DIType CGDebugInfo::CreateType(con
>    RecordDecl *RD = Ty->getDecl();
>    // Limited debug info should only remove struct definitions that can
>    // safely be replaced by a forward declaration in the source code.
> -  if (DebugKind <= CodeGenOptions::LimitedDebugInfo && Declaration) {
> +  if (DebugKind <= CodeGenOptions::LimitedDebugInfo && Declaration &&
> +      !RD->isCompleteDefinitionRequired()) {
>      // FIXME: This implementation is problematic; there are some test
>      // cases where we violate the above principle, such as
>      // test/CodeGen/debug-info-records.c .
>
> Modified: cfe/trunk/lib/CodeGen/CGExprCXX.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprCXX.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExprCXX.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExprCXX.cpp Sat Jul 13 16:08:14 2013
> @@ -175,17 +175,6 @@ RValue CodeGenFunction::EmitCXXMemberCal
>    const MemberExpr *ME = cast<MemberExpr>(callee);
>    const CXXMethodDecl *MD = cast<CXXMethodDecl>(ME->getMemberDecl());
>
> -  CGDebugInfo *DI = getDebugInfo();
> -  if (DI &&
> -      CGM.getCodeGenOpts().getDebugInfo() == CodeGenOptions::LimitedDebugInfo &&
> -      !isa<CallExpr>(ME->getBase())) {
> -    QualType PQTy = ME->getBase()->IgnoreParenImpCasts()->getType();
> -    if (const PointerType * PTy = dyn_cast<PointerType>(PQTy)) {
> -      DI->getOrCreateRecordType(PTy->getPointeeType(),
> -                                MD->getParent()->getLocation());
> -    }
> -  }
> -
>    if (MD->isStatic()) {
>      // The method is static, emit it as we would a regular call.
>      llvm::Value *Callee = CGM.GetAddrOfFunction(MD);
>
> Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Sat Jul 13 16:08:14 2013
> @@ -992,18 +992,6 @@ Value *ScalarExprEmitter::VisitMemberExp
>      return Builder.getInt(Value);
>    }
>
> -  // Emit debug info for aggregate now, if it was delayed to reduce
> -  // debug info size.
> -  CGDebugInfo *DI = CGF.getDebugInfo();
> -  if (DI &&
> -      CGF.CGM.getCodeGenOpts().getDebugInfo()
> -        == CodeGenOptions::LimitedDebugInfo) {
> -    QualType PQTy = E->getBase()->IgnoreParenImpCasts()->getType();
> -    if (const PointerType * PTy = dyn_cast<PointerType>(PQTy))
> -      if (FieldDecl *M = dyn_cast<FieldDecl>(E->getMemberDecl()))
> -        DI->getOrCreateRecordType(PTy->getPointeeType(),
> -                                  M->getParent()->getLocation());
> -  }
>    return EmitLoadOfLValue(E);
>  }
>
>
> Modified: cfe/trunk/lib/CodeGen/CodeGenAction.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CodeGenAction.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/CodeGenAction.cpp (original)
> +++ cfe/trunk/lib/CodeGen/CodeGenAction.cpp Sat Jul 13 16:08:14 2013
> @@ -171,6 +171,10 @@ namespace clang {
>        Gen->HandleTagDeclDefinition(D);
>      }
>
> +    virtual void HandleTagDeclRequiredDefinition(const TagDecl *D) {
> +      Gen->HandleTagDeclRequiredDefinition(D);
> +    }
> +
>      virtual void CompleteTentativeDefinition(VarDecl *D) {
>        Gen->CompleteTentativeDefinition(D);
>      }
>
> Modified: cfe/trunk/lib/CodeGen/ModuleBuilder.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/ModuleBuilder.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/CodeGen/ModuleBuilder.cpp (original)
> +++ cfe/trunk/lib/CodeGen/ModuleBuilder.cpp Sat Jul 13 16:08:14 2013
> @@ -13,6 +13,7 @@
>
>  #include "clang/CodeGen/ModuleBuilder.h"
>  #include "CodeGenModule.h"
> +#include "CGDebugInfo.h"
>  #include "clang/AST/ASTContext.h"
>  #include "clang/AST/DeclObjC.h"
>  #include "clang/AST/Expr.h"
> @@ -93,6 +94,12 @@ namespace {
>        }
>      }
>
> +    virtual void HandleTagDeclRequiredDefinition(const TagDecl *D) LLVM_OVERRIDE {
> +      if (CodeGen::CGDebugInfo *DI = Builder->getModuleDebugInfo())
> +        if (const RecordDecl *RD = dyn_cast<RecordDecl>(D))
> +          DI->completeFwdDecl(*RD);
> +    }
> +
>      virtual void HandleTranslationUnit(ASTContext &Ctx) {
>        if (Diags.hasErrorOccurred()) {
>          M.reset();
>
> Modified: cfe/trunk/lib/Sema/SemaType.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaType.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/lib/Sema/SemaType.cpp (original)
> +++ cfe/trunk/lib/Sema/SemaType.cpp Sat Jul 13 16:08:14 2013
> @@ -12,6 +12,7 @@
>  //===----------------------------------------------------------------------===//
>
>  #include "clang/Sema/SemaInternal.h"
> +#include "clang/AST/ASTConsumer.h"
>  #include "clang/AST/ASTContext.h"
>  #include "clang/AST/ASTMutationListener.h"
>  #include "clang/AST/CXXInheritance.h"
> @@ -4844,6 +4845,20 @@ bool Sema::RequireCompleteExprType(Expr
>  /// @c false otherwise.
>  bool Sema::RequireCompleteType(SourceLocation Loc, QualType T,
>                                 TypeDiagnoser &Diagnoser) {
> +  if (RequireCompleteTypeImpl(Loc, T, Diagnoser))
> +    return true;
> +  if (const TagType *Tag = T->getAs<TagType>()) {
> +    if (!Tag->getDecl()->isCompleteDefinitionRequired()) {
> +      Tag->getDecl()->setCompleteDefinitionRequired();
> +      Consumer.HandleTagDeclRequiredDefinition(Tag->getDecl());
> +    }
> +  }
> +  return false;
> +}
> +
> +/// \brief The implementation of RequireCompleteType
> +bool Sema::RequireCompleteTypeImpl(SourceLocation Loc, QualType T,
> +                                   TypeDiagnoser &Diagnoser) {
>    // FIXME: Add this assertion to make sure we always get instantiation points.
>    //  assert(!Loc.isInvalid() && "Invalid location in RequireCompleteType");
>    // FIXME: Add this assertion to help us flush out problems with
>
> Modified: cfe/trunk/test/CodeGenCXX/debug-info-class-limited.cpp
> URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGenCXX/debug-info-class-limited.cpp?rev=186262&r1=186261&r2=186262&view=diff
> ==============================================================================
> --- cfe/trunk/test/CodeGenCXX/debug-info-class-limited.cpp (original)
> +++ cfe/trunk/test/CodeGenCXX/debug-info-class-limited.cpp Sat Jul 13 16:08:14 2013
> @@ -1,8 +1,7 @@
>  // RUN: %clang -emit-llvm -g -S %s -o - | FileCheck %s
>
>  namespace PR16214_1 {
> -// CHECK: [[PR16214_1:![0-9]*]] = {{.*}} [ DW_TAG_namespace ] [PR16214_1]
> -// CHECK: = metadata !{i32 {{[0-9]*}}, metadata !{{[0-9]*}}, metadata [[PR16214_1]], {{.*}} ; [ DW_TAG_structure_type ] [foo] {{.*}} [def]
> +// CHECK-DAG: [ DW_TAG_structure_type ] [foo] [line [[@LINE+1]], {{.*}} [def]
>  struct foo {
>    int i;
>  };
> @@ -13,9 +12,9 @@ bar *a;
>  bar b;
>  }
>
> -namespace test1 {
> +namespace PR14467 {
> +// CHECK-DAG: [ DW_TAG_structure_type ] [foo] [line [[@LINE+1]], {{.*}} [def]
>  struct foo {
> -  int i;
>  };
>
>  foo *bar(foo *a) {
> @@ -24,9 +23,9 @@ foo *bar(foo *a) {
>  }
>  }
>
> -namespace test2 {
> +namespace test1 {
> +// CHECK-DAG: [ DW_TAG_structure_type ] [foo] [line [[@LINE+1]], {{.*}} [decl]
>  struct foo {
> -  int i;
>  };
>
>  extern int bar(foo *a);
> @@ -34,3 +33,20 @@ int baz(foo *a) {
>    return bar(a);
>  }
>  }
> +
> +namespace test2 {
> +// FIXME: if we were a bit fancier, we could realize that the 'foo' type is only
> +// required because of the 'bar' type which is not required at all (or might
> +// only be required to be declared)
> +// CHECK-DAG: [ DW_TAG_structure_type ] [foo] [line [[@LINE+1]], {{.*}} [def]
> +struct foo {
> +};
> +
> +struct bar {
> +  foo f;
> +};
> +
> +void func() {
> +  foo *f;
> +}
> +}
>
>
> _______________________________________________
> cfe-commits mailing list
> cfe-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits



More information about the cfe-commits mailing list