From 5b9a072c39c0c34a290abd19e4aca8208a9afae6 Mon Sep 17 00:00:00 2001 From: Hans Wennborg Date: Thu, 7 Nov 2019 10:23:24 +0100 Subject: [PATCH] Revert a5c8ec4 "[CGDebugInfo] Emit subprograms for decls when AT_tail_call is understood" This caused Chromium builds to fail with "inlinable function call in a function with debug info must have a !dbg location" errors. See https://bugs.chromium.org/p/chromium/issues/detail?id=1022296#c1 for a reproducer. > Currently, clang emits subprograms for declared functions when the > target debugger or DWARF standard is known to support entry values > (DW_OP_entry_value & the GNU equivalent). > > Treat DW_AT_tail_call the same way to allow debuggers to follow cross-TU > tail calls. > > Pre-patch debug session with a cross-TU tail call: > > ``` > * frame #0: 0x0000000100000fa4 main`target at b.c:4:3 [opt] > frame #1: 0x0000000100000f99 main`main at a.c:8:10 [opt] > ``` > > Post-patch (note that the tail-calling frame, "helper", is visible): > > ``` > * frame #0: 0x0000000100000fa4 main`target at b.c:4:3 [opt] > frame #1: 0x0000000100000f80 main`helper [opt] [artificial] > frame #2: 0x0000000100000f99 main`main at a.c:8:10 [opt] > ``` > > rdar://46577651 > > Differential Revision: https://reviews.llvm.org/D69743 --- clang/lib/CodeGen/CGDebugInfo.cpp | 10 ++++++---- clang/test/CodeGen/debug-info-extern-call.c | 21 ++++----------------- .../CodeGenCXX/dbg-info-all-calls-described.cpp | 1 - .../DebugInfo/X86/dwarf-callsite-related-attrs.ll | 9 --------- 4 files changed, 10 insertions(+), 31 deletions(-) diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp index c0c8fd3..e0bb3fd 100644 --- a/clang/lib/CodeGen/CGDebugInfo.cpp +++ b/clang/lib/CodeGen/CGDebugInfo.cpp @@ -3748,7 +3748,9 @@ void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke, QualType CalleeType, const FunctionDecl *CalleeDecl) { - if (!CallOrInvoke || getCallSiteRelatedAttrs() == llvm::DINode::FlagZero) + auto &CGOpts = CGM.getCodeGenOpts(); + if (!CGOpts.EnableDebugEntryValues || !CGM.getLangOpts().Optimize || + !CallOrInvoke) return; auto *Func = CallOrInvoke->getCalledFunction(); @@ -4822,10 +4824,10 @@ llvm::DINode::DIFlags CGDebugInfo::getCallSiteRelatedAttrs() const { bool SupportsDWARFv4Ext = CGM.getCodeGenOpts().DwarfVersion == 4 && (CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::LLDB || - CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::GDB); + (CGM.getCodeGenOpts().EnableDebugEntryValues && + CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::GDB)); - if (!SupportsDWARFv4Ext && CGM.getCodeGenOpts().DwarfVersion < 5 && - !CGM.getCodeGenOpts().EnableDebugEntryValues) + if (!SupportsDWARFv4Ext && CGM.getCodeGenOpts().DwarfVersion < 5) return llvm::DINode::FlagZero; return llvm::DINode::FlagAllCallsDescribed; diff --git a/clang/test/CodeGen/debug-info-extern-call.c b/clang/test/CodeGen/debug-info-extern-call.c index 7f58fe5..e35669b 100644 --- a/clang/test/CodeGen/debug-info-extern-call.c +++ b/clang/test/CodeGen/debug-info-extern-call.c @@ -1,21 +1,8 @@ -// When entry values are emitted, expect a subprogram for extern decls so that -// the dwarf generator can describe call site parameters at extern call sites. -// -// RUN: %clang -Xclang -femit-debug-entry-values -g -O2 -target x86_64-none-linux-gnu -S -emit-llvm %s -o - | FileCheck %s -check-prefix=ENTRY-VAL -// ENTRY-VAL: !DISubprogram(name: "fn1" +// RUN: %clang -Xclang -femit-debug-entry-values -g -O2 -target x86_64-none-linux-gnu -S -emit-llvm %s -o - | FileCheck %s -check-prefix=CHECK-EXT +// CHECK-EXT: !DISubprogram(name: "fn1" -// Similarly, when the debugger tuning is gdb, expect a subprogram for extern -// decls so that the dwarf generator can describe information needed for tail -// call frame reconstrution. -// -// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -ggdb -S -emit-llvm %s -o - | FileCheck %s -check-prefix=GDB -// GDB: !DISubprogram(name: "fn1" -// -// Do not emit a subprogram for extern decls when entry values are disabled and -// the tuning is not set to gdb. -// -// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -gsce -S -emit-llvm %s -o - | FileCheck %s -check-prefix=SCE -// SCE-NOT: !DISubprogram(name: "fn1" +// RUN: %clang -g -O2 -target x86_64-none-linux-gnu -S -emit-llvm %s -o - | FileCheck %s +// CHECK-NOT: !DISubprogram(name: "fn1" extern int fn1(int a, int b); diff --git a/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp b/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp index 667c246..1cb2b6c 100644 --- a/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp +++ b/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp @@ -56,7 +56,6 @@ // NO-ATTR-NOT: FlagAllCallsDescribed -// HAS-ATTR-DAG: DISubprogram(name: "declaration1", {{.*}}, flags: DIFlagPrototyped // HAS-ATTR-DAG: DISubprogram(name: "declaration2", {{.*}}, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition // HAS-ATTR-DAG: DISubprogram(name: "struct1", {{.*}}, flags: DIFlagPrototyped, spFlags: DISPFlagOptimized) // HAS-ATTR-DAG: DISubprogram(name: "struct1", {{.*}}, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition diff --git a/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll b/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll index 33e06fa..c37ce1e 100644 --- a/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll +++ b/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll @@ -25,14 +25,6 @@ @sink = global i32 0, align 4, !dbg !0 -define void @__has_no_subprogram() { -entry: - %0 = load volatile i32, i32* @sink, align 4 - %inc = add nsw i32 %0, 1 - store volatile i32 %inc, i32* @sink, align 4 - ret void -} - ; ASM: DW_TAG_subprogram ; ASM: DW_AT_call_all_calls ; OBJ: [[bat_sp:.*]]: DW_TAG_subprogram @@ -78,7 +70,6 @@ entry: ; OBJ: DW_AT_call_tail_call define void @_Z3foov() !dbg !25 { entry: - tail call void @__has_no_subprogram() tail call void @_Z3barv(), !dbg !26 tail call void @_Z3batv(), !dbg !27 tail call void @_Z3barv(), !dbg !26 -- 2.7.4