[llvm] a5c8ec4 - [CGDebugInfo] Emit subprograms for decls when AT_tail_call is understood
Eric Christopher via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 7 09:09:18 PST 2019
Thanks Hans!
On Thu, Nov 7, 2019, 1:32 AM Hans Wennborg <hans at chromium.org> wrote:
> In Chromium it broke the build in a few configurations, so I've
> reverted in 5b9a072c39c.
>
> See https://bugs.chromium.org/p/chromium/issues/detail?id=1022296#c1
> for reproducer.
>
> On Thu, Nov 7, 2019 at 3:05 AM Eric Christopher via llvm-commits
> <llvm-commits at lists.llvm.org> wrote:
> >
> > As a heads up we're starting to see a problem around this commit with
> > backtraces for inline functions with msan where the line number has
> > gone away (replaced with 0).
> >
> > Dave is looking at it, but I thought I'd send a message as early as I
> could.
> >
> > -eric
> >
> > On Mon, Nov 4, 2019 at 3:14 PM Vedant Kumar via llvm-commits
> > <llvm-commits at lists.llvm.org> wrote:
> > >
> > >
> > > 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
> > >
> > >
> > >
> > > _______________________________________________
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> > > llvm-commits at lists.llvm.org
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