From 0779dffbd4a927d7bf9523482481248c51796907 Mon Sep 17 00:00:00 2001 From: Adrian Prantl Date: Wed, 18 Sep 2019 22:38:56 +0000 Subject: [PATCH] Remove the obsolete BlockByRefStruct flag from LLVM IR DIFlagBlockByRefStruct is an unused DIFlag that originally was used by clang to express (Objective-)C block captures in debug info. For the last year Clang has been emitting complex DIExpressions to describe block captures instead, which makes all the code supporting this flag redundant. This patch removes the flag and all supporting "dead" code, so we can reuse the bit for something else in the future. Since this only affects debug info generated by Clang with the block extension this mostly affects Apple platforms and I don't have any bitcode compatibility concerns for removing this. The Verifier will reject debug info that uses the bit and thus degrade gracefully when LTO'ing older bitcode with a newer compiler. rdar://problem/44304813 Differential Revision: https://reviews.llvm.org/D67453 llvm-svn: 372272 --- llvm/bindings/go/llvm/dibuilder.go | 2 +- llvm/include/llvm-c/DebugInfo.h | 2 +- llvm/include/llvm/IR/DebugInfoFlags.def | 3 +- llvm/include/llvm/IR/DebugInfoMetadata.h | 1 - .../CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 8 ---- llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 48 +------------------ llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h | 1 - llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h | 9 ---- llvm/lib/IR/Verifier.cpp | 8 ++-- llvm/test/CodeGen/ARM/debug-info-blocks.ll | 2 +- llvm/test/DebugInfo/Generic/block-asan.ll | 2 +- llvm/test/Verifier/blockbyref.ll | 4 +- 12 files changed, 12 insertions(+), 78 deletions(-) diff --git a/llvm/bindings/go/llvm/dibuilder.go b/llvm/bindings/go/llvm/dibuilder.go index 98c11c151153b8..2c6bee411c0eca 100644 --- a/llvm/bindings/go/llvm/dibuilder.go +++ b/llvm/bindings/go/llvm/dibuilder.go @@ -44,7 +44,7 @@ const ( FlagProtected FlagFwdDecl FlagAppleBlock - FlagBlockByrefStruct + FlagReserved FlagVirtual FlagArtificial FlagExplicit diff --git a/llvm/include/llvm-c/DebugInfo.h b/llvm/include/llvm-c/DebugInfo.h index 33c8110a863c00..c96faa2fbba4ef 100644 --- a/llvm/include/llvm-c/DebugInfo.h +++ b/llvm/include/llvm-c/DebugInfo.h @@ -32,7 +32,7 @@ typedef enum { LLVMDIFlagPublic = 3, LLVMDIFlagFwdDecl = 1 << 2, LLVMDIFlagAppleBlock = 1 << 3, - LLVMDIFlagBlockByrefStruct = 1 << 4, + LLVMDIFlagReservedBit4 = 1 << 4, LLVMDIFlagVirtual = 1 << 5, LLVMDIFlagArtificial = 1 << 6, LLVMDIFlagExplicit = 1 << 7, diff --git a/llvm/include/llvm/IR/DebugInfoFlags.def b/llvm/include/llvm/IR/DebugInfoFlags.def index c6c696523fbb5f..f90c580f10ef11 100644 --- a/llvm/include/llvm/IR/DebugInfoFlags.def +++ b/llvm/include/llvm/IR/DebugInfoFlags.def @@ -31,7 +31,8 @@ HANDLE_DI_FLAG(2, Protected) HANDLE_DI_FLAG(3, Public) HANDLE_DI_FLAG((1 << 2), FwdDecl) HANDLE_DI_FLAG((1 << 3), AppleBlock) -HANDLE_DI_FLAG((1 << 4), BlockByrefStruct) +// Used to be BlockByRef, can be reused for anything except DICompositeType. +HANDLE_DI_FLAG((1 << 4), ReservedBit4) HANDLE_DI_FLAG((1 << 5), Virtual) HANDLE_DI_FLAG((1 << 6), Artificial) HANDLE_DI_FLAG((1 << 7), Explicit) diff --git a/llvm/include/llvm/IR/DebugInfoMetadata.h b/llvm/include/llvm/IR/DebugInfoMetadata.h index 1f0533d98f63ad..b94640f1771222 100644 --- a/llvm/include/llvm/IR/DebugInfoMetadata.h +++ b/llvm/include/llvm/IR/DebugInfoMetadata.h @@ -650,7 +650,6 @@ class DIType : public DIScope { } bool isForwardDecl() const { return getFlags() & FlagFwdDecl; } bool isAppleBlockExtension() const { return getFlags() & FlagAppleBlock; } - bool isBlockByrefStruct() const { return getFlags() & FlagBlockByrefStruct; } bool isVirtual() const { return getFlags() & FlagVirtual; } bool isArtificial() const { return getFlags() & FlagArtificial; } bool isObjectPointer() const { return getFlags() & FlagObjectPointer; } diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp index f859a02033b4ba..edc8cefa3e22fe 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp @@ -1165,16 +1165,8 @@ void DwarfCompileUnit::addGlobalTypeUnitType(const DIType *Ty, GlobalTypes.insert(std::make_pair(std::move(FullName), &getUnitDie())); } -/// addVariableAddress - Add DW_AT_location attribute for a -/// DbgVariable based on provided MachineLocation. void DwarfCompileUnit::addVariableAddress(const DbgVariable &DV, DIE &Die, MachineLocation Location) { - // addBlockByrefAddress is obsolete and will be removed soon. - // The clang frontend always generates block byref variables with a - // complex expression that encodes exactly what addBlockByrefAddress - // would do. - assert((!DV.isBlockByrefVariable() || DV.hasComplexAddress()) && - "block byref variable without a complex expression"); if (DV.hasComplexAddress()) addComplexAddress(DV, Die, dwarf::DW_AT_location, Location); else diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index 9be64c42f0cd2e..255203740ac7c2 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -198,54 +198,8 @@ bool DebugLocDwarfExpression::isFrameRegister(const TargetRegisterInfo &TRI, return false; } -bool DbgVariable::isBlockByrefVariable() const { - assert(getVariable() && "Invalid complex DbgVariable!"); - return getVariable()->getType()->isBlockByrefStruct(); -} - const DIType *DbgVariable::getType() const { - DIType *Ty = getVariable()->getType(); - // FIXME: isBlockByrefVariable should be reformulated in terms of complex - // addresses instead. - if (Ty->isBlockByrefStruct()) { - /* Byref variables, in Blocks, are declared by the programmer as - "SomeType VarName;", but the compiler creates a - __Block_byref_x_VarName struct, and gives the variable VarName - either the struct, or a pointer to the struct, as its type. This - is necessary for various behind-the-scenes things the compiler - needs to do with by-reference variables in blocks. - - However, as far as the original *programmer* is concerned, the - variable should still have type 'SomeType', as originally declared. - - The following function dives into the __Block_byref_x_VarName - struct to find the original type of the variable. This will be - passed back to the code generating the type for the Debug - Information Entry for the variable 'VarName'. 'VarName' will then - have the original type 'SomeType' in its debug information. - - The original type 'SomeType' will be the type of the field named - 'VarName' inside the __Block_byref_x_VarName struct. - - NOTE: In order for this to not completely fail on the debugger - side, the Debug Information Entry for the variable VarName needs to - have a DW_AT_location that tells the debugger how to unwind through - the pointers and __Block_byref_x_VarName struct to find the actual - value of the variable. The function addBlockByrefType does this. */ - DIType *subType = Ty; - uint16_t tag = Ty->getTag(); - - if (tag == dwarf::DW_TAG_pointer_type) - subType = cast(Ty)->getBaseType(); - - auto Elements = cast(subType)->getElements(); - for (unsigned i = 0, N = Elements.size(); i < N; ++i) { - auto *DT = cast(Elements[i]); - if (getName() == DT->getName()) - return DT->getBaseType(); - } - } - return Ty; + return getVariable()->getType(); } /// Get .debug_loc entry for the instruction range starting at MI. diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h index 843caf1ab184f4..c8c511f67c2a09 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h @@ -216,7 +216,6 @@ class DbgVariable : public DbgEntity { return !FrameIndexExprs.empty(); } - bool isBlockByrefVariable() const; const DIType *getType() const; static bool classof(const DbgEntity *N) { diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h index a376d5e75f6752..a188002722d2f6 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.h @@ -216,15 +216,6 @@ class DwarfUnit : public DIEUnit { /// Add thrown types. void addThrownTypes(DIE &Die, DINodeArray ThrownTypes); - // FIXME: Should be reformulated in terms of addComplexAddress. - /// Start with the address based on the location provided, and generate the - /// DWARF information necessary to find the actual Block variable (navigating - /// the Block struct) based on the starting location. Add the DWARF - /// information to the die. Obsolete, please use addComplexAddress instead. - void addBlockByrefAddress(const DbgVariable &DV, DIE &Die, - dwarf::Attribute Attribute, - const MachineLocation &Location); - /// Add a new type attribute to the specified entity. /// /// This takes and attribute parameter because DW_AT_friend attributes are diff --git a/llvm/lib/IR/Verifier.cpp b/llvm/lib/IR/Verifier.cpp index 18bd74baf177a8..ebd4125f184efb 100644 --- a/llvm/lib/IR/Verifier.cpp +++ b/llvm/lib/IR/Verifier.cpp @@ -982,6 +982,9 @@ void Verifier::visitDICompositeType(const DICompositeType &N) { N.getRawVTableHolder()); AssertDI(!hasConflictingReferenceFlags(N.getFlags()), "invalid reference flags", &N); + unsigned DIBlockByRefStruct = 1 << 4; + AssertDI((N.getFlags() & DIBlockByRefStruct) == 0, + "DIBlockByRefStruct on DICompositeType is no longer supported", &N); if (N.isVector()) { const DINodeArray Elements = N.getElements(); @@ -4902,11 +4905,6 @@ void Verifier::visitDbgIntrinsic(StringRef Kind, DbgVariableIntrinsic &DII) { // This check is redundant with one in visitLocalVariable(). AssertDI(isType(Var->getRawType()), "invalid type ref", Var, Var->getRawType()); - if (auto *Type = dyn_cast_or_null(Var->getRawType())) - if (Type->isBlockByrefStruct()) - AssertDI(DII.getExpression() && DII.getExpression()->getNumElements(), - "BlockByRef variable without complex expression", Var, &DII); - verifyFnArgs(DII); } diff --git a/llvm/test/CodeGen/ARM/debug-info-blocks.ll b/llvm/test/CodeGen/ARM/debug-info-blocks.ll index cc1a45f23da077..8b31e7a51d5145 100644 --- a/llvm/test/CodeGen/ARM/debug-info-blocks.ll +++ b/llvm/test/CodeGen/ARM/debug-info-blocks.ll @@ -155,7 +155,7 @@ define hidden void @foobar_func_block_invoke_0(i8* %.block_descriptor, %0* %load !47 = !DIDerivedType(tag: DW_TAG_member, name: "DestroyFuncPtr", line: 307, size: 32, align: 32, offset: 96, file: !153, scope: !40, baseType: !46) !48 = !DIDerivedType(tag: DW_TAG_member, name: "mydata", line: 609, size: 32, align: 32, offset: 160, file: !152, scope: !24, baseType: !49) !49 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 32, scope: !0, baseType: !50) -!50 = !DICompositeType(tag: DW_TAG_structure_type, size: 224, flags: DIFlagBlockByrefStruct, file: !152, scope: !24, elements: !51) +!50 = !DICompositeType(tag: DW_TAG_structure_type, size: 224, file: !152, scope: !24, elements: !51) !51 = !{!52, !53, !54, !55, !56, !57, !58} !52 = !DIDerivedType(tag: DW_TAG_member, name: "__isa", size: 32, align: 32, file: !152, scope: !24, baseType: !32) !53 = !DIDerivedType(tag: DW_TAG_member, name: "__forwarding", size: 32, align: 32, offset: 32, file: !152, scope: !24, baseType: !32) diff --git a/llvm/test/DebugInfo/Generic/block-asan.ll b/llvm/test/DebugInfo/Generic/block-asan.ll index ee9a52522cfe62..1d706fc6b84e6d 100644 --- a/llvm/test/DebugInfo/Generic/block-asan.ll +++ b/llvm/test/DebugInfo/Generic/block-asan.ll @@ -70,7 +70,7 @@ attributes #3 = { nounwind } !10 = !{i32 1, !"PIC Level", i32 2} !11 = !{!"clang version 3.6.0 (trunk 223120) (llvm/trunk 223119)"} !12 = !DILocalVariable(name: "x", line: 4, scope: !4, file: !5, type: !13) -!13 = !DICompositeType(tag: DW_TAG_structure_type, size: 224, flags: DIFlagBlockByrefStruct, file: !1, scope: !5, elements: !14) +!13 = !DICompositeType(tag: DW_TAG_structure_type, size: 224, file: !1, scope: !5, elements: !14) !14 = !{!15, !17, !18, !20, !21} !15 = !DIDerivedType(tag: DW_TAG_member, name: "__isa", size: 64, align: 64, file: !1, scope: !5, baseType: !16) !16 = !DIDerivedType(tag: DW_TAG_pointer_type, size: 64, align: 64, baseType: null) diff --git a/llvm/test/Verifier/blockbyref.ll b/llvm/test/Verifier/blockbyref.ll index 037da7f0952107..14d705647b74af 100644 --- a/llvm/test/Verifier/blockbyref.ll +++ b/llvm/test/Verifier/blockbyref.ll @@ -1,6 +1,6 @@ ; RUN: llvm-as -disable-output <%s 2>&1| FileCheck %s -; CHECK: BlockByRef variable without complex expression +; CHECK: DIBlockByRefStruct on DICompositeType is no longer supported ; CHECK: warning: ignoring invalid debug info define void @foo() { @@ -16,4 +16,4 @@ declare void @llvm.dbg.declare(metadata, metadata, metadata) !0 = !{i32 2, !"Debug Info Version", i32 3} !1 = distinct !DISubprogram() !2 = !DILocalVariable(scope: !1, type: !3) -!3 = !DICompositeType(tag: DW_TAG_structure_type, flags: DIFlagBlockByrefStruct) +!3 = !DICompositeType(tag: DW_TAG_structure_type, flags: DIFlagReservedBit4)