From f345c4732c6e3edec4a51d4c31294c7fdbef4b2c Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Wed, 30 Apr 2014 21:29:41 +0000 Subject: [PATCH] Emit DW_AT_object_pointer once, on the declaration, for each function. This effectively reverts r164326, but adds some comments and justification and ensures we /don't/ emit the DW_AT_object_pointer on the (abstract and concrete) definitions. (while still preserving it on standalone definitions involving ObjC Blocks) This does increase the size of member function declarations from 7 to 11 bytes, unfortunately, but still seems like the Right Thing to do so that callers that see only the declaration still have the information about the object pointer. That said, I don't know what, if any, DWARF consumers don't have a heuristic to guess this in the case of normal C++ member functions - perhaps we can remove it entirely. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@207705 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 13 ++++++++---- lib/CodeGen/AsmPrinter/DwarfDebug.h | 2 +- lib/CodeGen/AsmPrinter/DwarfUnit.cpp | 9 +++++++-- lib/CodeGen/AsmPrinter/DwarfUnit.h | 2 +- test/DebugInfo/X86/DW_AT_object_pointer.ll | 21 +++++++++++++++++--- test/DebugInfo/X86/inline-member-function.ll | 15 +++++++++++--- 6 files changed, 48 insertions(+), 14 deletions(-) diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index ac4eea4a50b..d9ef6c04285 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -548,11 +548,16 @@ DIE *DwarfDebug::createScopeChildrenDIE( } void DwarfDebug::createAndAddScopeChildren(DwarfCompileUnit &TheCU, - LexicalScope *Scope, DIE &ScopeDIE) { + LexicalScope *Scope, + DISubprogram Sub, DIE &ScopeDIE) { // We create children when the scope DIE is not null. SmallVector, 8> Children; if (DIE *ObjectPointer = createScopeChildrenDIE(TheCU, Scope, Children)) - TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer); + // The declaration will have the object_pointer, otherwise put it on the + // definition. This happens with ObjC blocks that have object_pointer on + // non-member functions. + if (!Sub.getFunctionDeclaration()) + TheCU.addDIEEntry(ScopeDIE, dwarf::DW_AT_object_pointer, *ObjectPointer); // Add children for (auto &I : Children) @@ -571,7 +576,7 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU, if (DIE *ScopeDIE = TheCU.getDIE(Sub)) { AbstractSPDies.insert(std::make_pair(Sub, ScopeDIE)); - createAndAddScopeChildren(TheCU, Scope, *ScopeDIE); + createAndAddScopeChildren(TheCU, Scope, Sub, *ScopeDIE); } } @@ -588,7 +593,7 @@ DIE &DwarfDebug::constructSubprogramScopeDIE(DwarfCompileUnit &TheCU, DIE &ScopeDIE = updateSubprogramScopeDIE(TheCU, Sub); - createAndAddScopeChildren(TheCU, Scope, ScopeDIE); + createAndAddScopeChildren(TheCU, Scope, Sub, ScopeDIE); return ScopeDIE; } diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.h b/lib/CodeGen/AsmPrinter/DwarfDebug.h index d7359a3105e..16a314bdb32 100644 --- a/lib/CodeGen/AsmPrinter/DwarfDebug.h +++ b/lib/CodeGen/AsmPrinter/DwarfDebug.h @@ -371,7 +371,7 @@ class DwarfDebug : public AsmPrinterHandler { std::unique_ptr constructScopeDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope); void createAndAddScopeChildren(DwarfCompileUnit &TheCU, LexicalScope *Scope, - DIE &ScopeDIE); + DISubprogram Sub, DIE &ScopeDIE); /// \brief Construct a DIE for this abstract scope. void constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU, LexicalScope *Scope); diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp index 4210a55459d..852eda14d86 100644 --- a/lib/CodeGen/AsmPrinter/DwarfUnit.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfUnit.cpp @@ -1164,7 +1164,8 @@ void DwarfUnit::constructTypeDIE(DIE &Buffer, DIDerivedType DTy) { } /// constructSubprogramArguments - Construct function argument DIEs. -void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DIArray Args) { +DIE *DwarfUnit::constructSubprogramArguments(DIE &Buffer, DIArray Args) { + DIE *ObjectPointer = nullptr; for (unsigned i = 1, N = Args.getNumElements(); i < N; ++i) { DIDescriptor Ty = Args.getElement(i); if (Ty.isUnspecifiedParameter()) { @@ -1175,8 +1176,11 @@ void DwarfUnit::constructSubprogramArguments(DIE &Buffer, DIArray Args) { addType(Arg, DIType(Ty)); if (DIType(Ty).isArtificial()) addFlag(Arg, dwarf::DW_AT_artificial); + if (DIType(Ty).isObjectPointer()) + ObjectPointer = &Arg; } } + return ObjectPointer; } /// constructTypeDIE - Construct type DIE from DICompositeType. @@ -1497,7 +1501,8 @@ DIE *DwarfUnit::getOrCreateSubprogramDIE(DISubprogram SP) { // Add arguments. Do not add arguments for subprogram definition. They will // be handled while processing variables. - constructSubprogramArguments(SPDie, Args); + if (DIE *ObjectPointer = constructSubprogramArguments(SPDie, Args)) + addDIEEntry(SPDie, dwarf::DW_AT_object_pointer, *ObjectPointer); } if (SP.isArtificial()) diff --git a/lib/CodeGen/AsmPrinter/DwarfUnit.h b/lib/CodeGen/AsmPrinter/DwarfUnit.h index 5ce6595c88d..cf4bc991b25 100644 --- a/lib/CodeGen/AsmPrinter/DwarfUnit.h +++ b/lib/CodeGen/AsmPrinter/DwarfUnit.h @@ -416,7 +416,7 @@ public: bool isScopeAbstract); /// constructSubprogramArguments - Construct function argument DIEs. - void constructSubprogramArguments(DIE &Buffer, DIArray Args); + DIE *constructSubprogramArguments(DIE &Buffer, DIArray Args); /// Create a DIE with the given Tag, add the DIE to its parent, and /// call insertDIE if MD is not null. diff --git a/test/DebugInfo/X86/DW_AT_object_pointer.ll b/test/DebugInfo/X86/DW_AT_object_pointer.ll index 5fa96994a8b..7885514c2c6 100644 --- a/test/DebugInfo/X86/DW_AT_object_pointer.ll +++ b/test/DebugInfo/X86/DW_AT_object_pointer.ll @@ -1,13 +1,28 @@ ; RUN: llc -mtriple=x86_64-apple-darwin %s -o %t -filetype=obj ; RUN: llvm-dwarfdump -debug-dump=info %t | FileCheck %s -; CHECK: DW_TAG_formal_parameter [ -; CHECK-NOT: "" +; Emit the DW_TAG_object_pointer on the declaration only, not the definition. +; This seems the most correct thing - the DW_TAG_object_pointer is inherited +; from the declaration to any (abstract or concrete) definitions and DWARF +; consumers can use this information for callers that can only see the +; declaration. +; That said, it isn't very space efficient - making member function +; declarations 11 bytes instead of 7 and I'm not sure which tools actually +; use this information here (ObjC Blocks are a different story & most likely +; require object_pointer) - perhaps we should omit it entirely for space. +; No overall space impact study has been performed. + +; CHECK: [[DEFINITION:0x[0-9a-f]*]]: DW_TAG_subprogram +; CHECK-NOT: DW_TAG +; CHECK-NOT: DW_TAG_object_pointer ; CHECK: DW_TAG + ; CHECK: DW_TAG_class_type +; CHECK-NOT: NULL +; CHECK: DW_TAG_subprogram +; CHECK-NEXT: DW_AT_name {{.*}} "A" ; CHECK: DW_AT_object_pointer [DW_FORM_ref4] (cu + 0x{{[0-9a-f]*}} => {[[PARAM:0x[0-9a-f]*]]}) ; CHECK: [[PARAM]]: DW_TAG_formal_parameter -; CHECK-NEXT: DW_AT_name [DW_FORM_strp] ( .debug_str[0x{{[0-9a-f]*}}] = "this") %class.A = type { i32 } diff --git a/test/DebugInfo/X86/inline-member-function.ll b/test/DebugInfo/X86/inline-member-function.ll index 9821a076b58..791d6466719 100644 --- a/test/DebugInfo/X86/inline-member-function.ll +++ b/test/DebugInfo/X86/inline-member-function.ll @@ -20,12 +20,21 @@ ; CHECK-NOT: DW_AT_object_pointer ; CHECK: DW_TAG -; But make sure we emit DW_AT_object_pointer on the abstract definition. -; CHECK: [[ABSTRACT_ORIGIN]]: DW_TAG_subprogram +; But make sure we emit DW_AT_object_pointer on the declaration. +; CHECK: DW_TAG_structure_type +; CHECK-NEXT: DW_AT_name {{.*}} "foo" ; CHECK-NOT: NULL -; CHECK-NOT: TAG +; CHECK: [[DECLARATION:0x[0-9a-e]*]]: DW_TAG_subprogram +; CHECK-NOT: DW_TAG ; CHECK: DW_AT_object_pointer +; But don't put it on the abstract definition, either. +; CHECK: [[ABSTRACT_ORIGIN]]: DW_TAG_subprogram +; CHECK-NEXT: DW_AT_specification {{.*}}{[[DECLARATION]]} +; CHECK-NOT: NULL +; CHECK-NOT: DW_AT_object_pointer +; CHECK: DW_TAG_formal_parameter + %struct.foo = type { i8 } @i = global i32 0, align 4 -- 2.34.1