[llvm] r204795 - Follow-up to r204790: don't try to emit line tables if there are no functions with DI in the TU

Wed Mar 26 13:00:50 PDT 2014

2014-03-26 19:24 GMT+04:00 David Blaikie <dblaikie at gmail.com>:

> On Wed, Mar 26, 2014 at 4:24 AM, Timur Iskhodzhanov <timurrrr at google.com>
> wrote:
> > Author: timurrrr
> > Date: Wed Mar 26 06:24:36 2014
> > New Revision: 204795
> >
> > URL: http://llvm.org/viewvc/llvm-project?rev=204795&view=rev
> > Log:
> > Follow-up to r204790: don't try to emit line tables if there are no
> functions with DI in the TU
>
> Hmm - is there any better way to do this? Should we only be building
> line tables for those functions with DI? Then we'd just emit line
> tables if we have any (non-empty) line tables to emit, right?
>

Is there a handy function available for that? :)

> I assume these COFF line tables don't actually get referenced from any
> other debug info (since the rest of our info is DWARF), but I've been
> thinking of cleaning up our other line table handling code a bit so
> that it's a bit more structured - letting the line table object itself
> decide whether it should be emitted (by virtue of being non-empty) and
> then having line table clients (CUs in DwarfDebug - no analogy for
> COFF which has no line table client) query the line table to see if
> it'll be there and attach the DW_AT_stmt_list if there will be a line
> table.
>
> - David
>
> >
> > Added:
> >     llvm/trunk/test/DebugInfo/COFF/asan2.ll
> > Modified:
> >     llvm/trunk/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
> >
> > Modified: llvm/trunk/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp?rev=204795&r1=204794&r2=204795&view=diff
> >
> ==============================================================================
> > --- llvm/trunk/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp
> (original)
> > +++ llvm/trunk/lib/CodeGen/AsmPrinter/WinCodeViewLineTables.cpp Wed Mar
> 26 06:24:36 2014
> > @@ -304,11 +304,18 @@ void WinCodeViewLineTables::beginFunctio
> >    }
> >  }
> >
> > -void WinCodeViewLineTables::endFunction(const MachineFunction *) {
> > +void WinCodeViewLineTables::endFunction(const MachineFunction *MF) {
> >    if (!Asm || !CurFn)  // We haven't created any debug info for this
> function.
> >      return;
> >
> > -  if (!CurFn->Instrs.empty()) {
> > +  const Function *GV = MF->getFunction();
> > +  assert(FnDebugInfo.count(GV) == true);
>
> "count == true" seems a bit confusing for a few reasons. Should that
> be either just "assert(x.count(y))" or "assert(x.count(y) != 0)" (or
> greater than zero or 1 or whatever). "== true" always reads as
> weird/redundant to me.
>
> > +  assert(CurFn == &FnDebugInfo[GV]);
> > +
> > +  if (CurFn->Instrs.empty()) {
> > +    FnDebugInfo.erase(GV);
> > +    VisitedFunctions.pop_back();
> > +  } else {
> >      // Define end label for subprogram.
> >      MCSymbol *FunctionEndSym =
> Asm->OutStreamer.getContext().CreateTempSymbol();
> >      Asm->OutStreamer.EmitLabel(FunctionEndSym);
> >
> > Added: llvm/trunk/test/DebugInfo/COFF/asan2.ll
> > URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/COFF/asan2.ll?rev=204795&view=auto
> >
> ==============================================================================
> > --- llvm/trunk/test/DebugInfo/COFF/asan2.ll (added)
> > +++ llvm/trunk/test/DebugInfo/COFF/asan2.ll Wed Mar 26 06:24:36 2014
> > @@ -0,0 +1,52 @@
> > +; RUN: llc -mcpu=core2 -mtriple=i686-pc-win32 -O0 < %s | FileCheck
> --check-prefix=X86 %s
> > +
> > +; This LL file was generated by running clang on the following code with
> > +; -fsanitize=address
> > +; D:\asan.c:
> > +; 1 unsigned char c = 42;
> > +
> > +; Just make sure we don't try to emit the line table.
> > +; X86-NOT: .section        .debug$S,"rn"
> > +
> > +; ModuleID = 'asan.c'
> > +target datalayout = "e-m:w-p:32:32-i64:64-f80:32-n8:16:32-S32"
> > +target triple = "i686-pc-win32"
> > +
> > + at c = global { i8, [63 x i8] } { i8 42, [63 x i8] zeroinitializer },
> align 32
> > + at llvm.global_ctors = appending global [1 x { i32, void ()* }] [{ i32,
> void ()* } { i32 1, void ()* @asan.module_ctor }]
> > + at __asan_gen_ = private constant [7 x i8] c"asan.c\00", align 1
> > + at __asan_gen_1 = private unnamed_addr constant [2 x i8] c"c\00", align 1
> > + at 0 = internal global [1 x { i32, i32, i32, i32, i32, i32 }] [{ i32,
> i32, i32, i32, i32, i32 } { i32 ptrtoint ({ i8, [63 x i8] }* @c to i32),
> i32 1, i32 64, i32 ptrtoint ([2 x i8]* @__asan_gen_1 to i32), i32 ptrtoint
> ([7 x i8]* @__asan_gen_ to i32), i32 0 }]
> > + at llvm.global_dtors = appending global [1 x { i32, void ()* }] [{ i32,
> void ()* } { i32 1, void ()* @asan.module_dtor }]
> > +
> > +define internal void @asan.module_ctor() {
> > +  call void @__asan_init_v3()
> > +  call void @__asan_register_globals(i32 ptrtoint ([1 x { i32, i32,
> i32, i32, i32, i32 }]* @0 to i32), i32 1)
> > +  ret void
> > +}
> > +
> > +declare void @__asan_init_v3()
> > +
> > +declare void @__asan_before_dynamic_init(i32)
> > +
> > +declare void @__asan_after_dynamic_init()
> > +
> > +declare void @__asan_register_globals(i32, i32)
> > +
> > +declare void @__asan_unregister_globals(i32, i32)
> > +
> > +define internal void @asan.module_dtor() {
> > +  call void @__asan_unregister_globals(i32 ptrtoint ([1 x { i32, i32,
> i32, i32, i32, i32 }]* @0 to i32), i32 1)
> > +  ret void
> > +}
> > +
> > +!llvm.dbg.cu = !{!0}
> > +!llvm.module.flags = !{!3, !4}
> > +!llvm.ident = !{!5}
> > +
> > +!0 = metadata !{i32 786449, metadata !1, i32 12, metadata !"clang
> version 3.5.0 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2,
> metadata !2, metadata !2, metadata !2, metadata !"", i32 2} ; [
> DW_TAG_compile_unit ] [D:\/asan.c] [DW_LANG_C99]
> > +!1 = metadata !{metadata !"asan.c", metadata !"D:\5C"}
> > +!2 = metadata !{}
> > +!3 = metadata !{i32 2, metadata !"Dwarf Version", i32 4}
> > +!4 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}
> > +!5 = metadata !{metadata !"clang version 3.5.0 "}
> >
> >
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>
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