Author: Vedant Kumar Date: 2019-11-04T15:14:24-08:00 New Revision: a5c8ec4baa2c00d8dbca36ffd236a40f9e0c07ed
URL: https://github.com/llvm/llvm-project/commit/a5c8ec4baa2c00d8dbca36ffd236a40f9e0c07ed DIFF: https://github.com/llvm/llvm-project/commit/a5c8ec4baa2c00d8dbca36ffd236a40f9e0c07ed.diff LOG: [CGDebugInfo] Emit subprograms for decls when AT_tail_call is understood 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 Added: Modified: clang/lib/CodeGen/CGDebugInfo.cpp clang/test/CodeGen/debug-info-extern-call.c clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll Removed: ################################################################################ diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp index e0bb3fda7acf..c0c8fd3c8f16 100644 --- a/clang/lib/CodeGen/CGDebugInfo.cpp +++ b/clang/lib/CodeGen/CGDebugInfo.cpp @@ -3748,9 +3748,7 @@ void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc, void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke, QualType CalleeType, const FunctionDecl *CalleeDecl) { - auto &CGOpts = CGM.getCodeGenOpts(); - if (!CGOpts.EnableDebugEntryValues || !CGM.getLangOpts().Optimize || - !CallOrInvoke) + if (!CallOrInvoke || getCallSiteRelatedAttrs() == llvm::DINode::FlagZero) return; auto *Func = CallOrInvoke->getCalledFunction(); @@ -4824,10 +4822,10 @@ llvm::DINode::DIFlags CGDebugInfo::getCallSiteRelatedAttrs() const { bool SupportsDWARFv4Ext = CGM.getCodeGenOpts().DwarfVersion == 4 && (CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::LLDB || - (CGM.getCodeGenOpts().EnableDebugEntryValues && - CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::GDB)); + CGM.getCodeGenOpts().getDebuggerTuning() == llvm::DebuggerKind::GDB); - if (!SupportsDWARFv4Ext && CGM.getCodeGenOpts().DwarfVersion < 5) + if (!SupportsDWARFv4Ext && CGM.getCodeGenOpts().DwarfVersion < 5 && + !CGM.getCodeGenOpts().EnableDebugEntryValues) 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 e35669b78f93..7f58fe59a635 100644 --- a/clang/test/CodeGen/debug-info-extern-call.c +++ b/clang/test/CodeGen/debug-info-extern-call.c @@ -1,8 +1,21 @@ -// 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" +// 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 -g -O2 -target x86_64-none-linux-gnu -S -emit-llvm %s -o - | FileCheck %s -// CHECK-NOT: !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" 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 1cb2b6c609f3..667c2469b55e 100644 --- a/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp +++ b/clang/test/CodeGenCXX/dbg-info-all-calls-described.cpp @@ -56,6 +56,7 @@ // 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 c37ce1eb7fbe..33e06faba57b 100644 --- a/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll +++ b/llvm/test/DebugInfo/X86/dwarf-callsite-related-attrs.ll @@ -25,6 +25,14 @@ @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 @@ -70,6 +78,7 @@ 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 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits