[llvm] r206665 - [llvm-symbolizer] Print file/line for a PC even if there is no DIE describing it.

[Eric Christopher]

I worry that this will give the inaccurate answers that we were
worried about without -gmlt turned on (inlining issues primarily).

Thoughts? Some, maybe slightly inaccurate, info is better than no info?

-eric

On Fri, Apr 18, 2014 at 3:22 PM, Alexey Samsonov <samsonov at google.com> wrote:
> Author: samsonov
> Date: Fri Apr 18 17:22:44 2014
> New Revision: 206665
>
> URL: http://llvm.org/viewvc/llvm-project?rev=206665&view=rev
> Log:
> [llvm-symbolizer] Print file/line for a PC even if there is no DIE describing it.
>
> This is important for symbolizing executables with debug info in
> unavailable .dwo files. Even if all DIE entries are missing, we can
> still symbolize an address: function name can be fetched from symbol table,
> and file/line info can be fetched from line table.
>
> Added:
>     llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test   (with props)
>     llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test.cc
> Modified:
>     llvm/trunk/lib/DebugInfo/DWARFContext.cpp
>     llvm/trunk/test/DebugInfo/llvm-symbolizer.test
>
> Modified: llvm/trunk/lib/DebugInfo/DWARFContext.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/DWARFContext.cpp?rev=206665&r1=206664&r2=206665&view=diff
> ==============================================================================
> --- llvm/trunk/lib/DebugInfo/DWARFContext.cpp (original)
> +++ llvm/trunk/lib/DebugInfo/DWARFContext.cpp Fri Apr 18 17:22:44 2014
> @@ -545,18 +545,32 @@ DILineInfoTable DWARFContext::getLineInf
>
>  DIInliningInfo DWARFContext::getInliningInfoForAddress(uint64_t Address,
>      DILineInfoSpecifier Specifier) {
> +  DIInliningInfo InliningInfo;
> +
>    DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
>    if (!CU)
> -    return DIInliningInfo();
> +    return InliningInfo;
>
> +  const DWARFLineTable *LineTable = nullptr;
> +  const bool NeedsAbsoluteFilePath =
> +      Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
>    const DWARFDebugInfoEntryInlinedChain &InlinedChain =
>        CU->getInlinedChainForAddress(Address);
> -  if (InlinedChain.DIEs.size() == 0)
> -    return DIInliningInfo();
> +  if (InlinedChain.DIEs.size() == 0) {
> +    // If there is no DIE for address (e.g. it is in unavailable .dwo file),
> +    // try to at least get file/line info from symbol table.
> +    if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
> +      DILineInfo Frame;
> +      LineTable = getLineTableForCompileUnit(CU);
> +      if (getFileLineInfoForCompileUnit(CU, LineTable, Address,
> +                                        NeedsAbsoluteFilePath, Frame)) {
> +        InliningInfo.addFrame(Frame);
> +      }
> +    }
> +    return InliningInfo;
> +  }
>
> -  DIInliningInfo InliningInfo;
>    uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
> -  const DWARFLineTable *LineTable = nullptr;
>    for (uint32_t i = 0, n = InlinedChain.DIEs.size(); i != n; i++) {
>      const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain.DIEs[i];
>      DILineInfo Frame;
> @@ -566,16 +580,13 @@ DIInliningInfo DWARFContext::getInlining
>          Frame.FunctionName = Name;
>      }
>      if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
> -      const bool NeedsAbsoluteFilePath =
> -          Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
>        if (i == 0) {
>          // For the topmost frame, initialize the line table of this
>          // compile unit and fetch file/line info from it.
>          LineTable = getLineTableForCompileUnit(CU);
>          // For the topmost routine, get file/line info from line table.
>          getFileLineInfoForCompileUnit(CU, LineTable, Address,
> -                                      NeedsAbsoluteFilePath,
> -                                      Frame);
> +                                      NeedsAbsoluteFilePath, Frame);
>        } else {
>          // Otherwise, use call file, call line and call column from
>          // previous DIE in inlined chain.
>
> Added: llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test?rev=206665&view=auto
> ==============================================================================
> Binary file - no diff available.
>
> Propchange: llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test
> ------------------------------------------------------------------------------
>     svn:executable = *
>
> Propchange: llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test
> ------------------------------------------------------------------------------
>     svn:mime-type = application/octet-stream
>
> Added: llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test.cc
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test.cc?rev=206665&view=auto
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test.cc (added)
> +++ llvm/trunk/test/DebugInfo/Inputs/llvm-symbolizer-dwo-test.cc Fri Apr 18 17:22:44 2014
> @@ -0,0 +1,18 @@
> +int f(int a, int b) {
> +  return a + b;
> +}
> +
> +int g(int a) {
> +  return a + 1;
> +}
> +
> +
> +int main() {
> +  return f(2, g(2));
> +}
> +
> +// Built with Clang 3.5.0:
> +// $ mkdir -p /tmp/dbginfo
> +// $ cp llvm-symbolizer-dwo-test.cc /tmp/dbginfo
> +// $ cd /tmp/dbginfo
> +// $ clang -gsplit-dwarf llvm-symbolizer-dwo-test.cc
>
> Modified: llvm/trunk/test/DebugInfo/llvm-symbolizer.test
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/llvm-symbolizer.test?rev=206665&r1=206664&r2=206665&view=diff
> ==============================================================================
> --- llvm/trunk/test/DebugInfo/llvm-symbolizer.test (original)
> +++ llvm/trunk/test/DebugInfo/llvm-symbolizer.test Fri Apr 18 17:22:44 2014
> @@ -8,6 +8,7 @@ RUN: echo "\"%p/Inputs/dwarfdump-test3.e
>  RUN: echo "%p/Inputs/macho-universal 0x1f84" >> %t.input
>  RUN: echo "%p/Inputs/macho-universal:i386 0x1f67" >> %t.input
>  RUN: echo "%p/Inputs/macho-universal:x86_64 0x100000f05" >> %t.input
> +RUN: echo "%p/Inputs/llvm-symbolizer-dwo-test 0x400514" >> %t.input
>
>  RUN: llvm-symbolizer --functions --inlining --demangle=false \
>  RUN:    --default-arch=i386 < %t.input | FileCheck %s
> @@ -48,6 +49,9 @@ CHECK:      main
>  CHECK:      _Z3inci
>  CHECK:      _Z3inci
>
> +CHECK: main
> +CHECK-NEXT: llvm-symbolizer-dwo-test.cc:11
> +
>  RUN: echo "unexisting-file 0x1234" > %t.input2
>  RUN: llvm-symbolizer < %t.input2
>
>
>
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