[PATCH v4] covoar: Handle periods in symbols from objdump

[Gedare Bloom]

this one looks fine to me.

On Fri, Mar 26, 2021 at 3:21 PM Alex White <alex.white at oarcorp.com> wrote:
>
> ping
>
> > -----Original Message-----
> > From: Alex White <alex.white at oarcorp.com>
> > Sent: Friday, March 19, 2021 2:10 PM
> > To: devel at rtems.org
> > Cc: Alex White <alex.white at oarcorp.com>
> > Subject: [PATCH v4] covoar: Handle periods in symbols from objdump
> >
> > Occasionally the compiler will generate symbols that look similar to symbols
> > defined in RTEMS code except that they contain some suffix.
> > These symbol suffixes are only found in the ELF symbol table; the symbols
> > appear to be normal in the DWARF info. This appears to be happening on all
> > architectures.
> >
> > For example, the function _Message_queue_Create from rtems appears as
> > "_Message_queue_Create.part.0". Other suffixes include ".isra.0",
> > ".constprop.0", and ".0".
> >
> > This looks to be related to compiler optimizations. Symbols with suffixes
> > were being treated as unique. For our purposes, they should be mapped to
> > the equivalent symbols in the DWARF info. This has been fixed.
> > ---
> >  tester/covoar/ExecutableInfo.cc   |  3 +--
> >  tester/covoar/ObjdumpProcessor.cc | 15 +++++++++++++++
> >  tester/covoar/SymbolTable.cc      | 12 +++++++++---
> >  3 files changed, 25 insertions(+), 5 deletions(-)
> >
> > diff --git a/tester/covoar/ExecutableInfo.cc
> > b/tester/covoar/ExecutableInfo.cc index c996d75..1e14721 100644
> > --- a/tester/covoar/ExecutableInfo.cc
> > +++ b/tester/covoar/ExecutableInfo.cc
> > @@ -118,8 +118,7 @@ namespace Coverage {
> >      // Obtain the coverage map containing the specified address.
> >      itsSymbol = theSymbolTable.getSymbol( address );
> >      if (itsSymbol != "") {
> > -      it = coverageMaps.find( itsSymbol );
> > -      aCoverageMap = (*it).second;
> > +      aCoverageMap = &findCoverageMap(itsSymbol);
> >      }
> >
> >      return aCoverageMap;
> > diff --git a/tester/covoar/ObjdumpProcessor.cc
> > b/tester/covoar/ObjdumpProcessor.cc
> > index 0647ff9..e19fa92 100644
> > --- a/tester/covoar/ObjdumpProcessor.cc
> > +++ b/tester/covoar/ObjdumpProcessor.cc
> > @@ -417,6 +417,21 @@ namespace Coverage {
> >          processSymbol = false;
> >          theInstructions.clear();
> >
> > +        // Look for a '.' character and strip everything after it.
> > +        // There is a chance that the compiler splits function bodies to improve
> > +        // inlining. If there exists some inlinable function that contains a
> > +        // branch where one path is more expensive and less likely to be taken
> > +        // than the other, inlining only the branch instruction and the less
> > +        // expensive path results in smaller code size while preserving most of
> > +        // the performance improvement.
> > +        // When this happens, the compiler will generate a function with a
> > +        // ".part.n" suffix. For our purposes, this generated function part is
> > +        // equivalent to the original function and should be treated as such.
> > +        char *periodIndex = strstr(symbol, ".");
> > +        if (periodIndex != NULL) {
> > +          *periodIndex = 0;
> > +        }
> > +
> >          // See if the new symbol is one that we care about.
> >          if (SymbolsToAnalyze->isDesired( symbol )) {
> >            currentSymbol = symbol;
> > diff --git a/tester/covoar/SymbolTable.cc b/tester/covoar/SymbolTable.cc
> > index 53bc8af..00062cc 100644
> > --- a/tester/covoar/SymbolTable.cc
> > +++ b/tester/covoar/SymbolTable.cc
> > @@ -46,12 +46,18 @@ namespace Coverage {
> >      symbolData.startingAddress = start;
> >      symbolData.length = length;
> >
> > -    if ( info[ symbol ].empty() == false ) {
> > -      if ( info[ symbol ].front().length != length ) {
> > +    for (auto& symData : info[ symbol ]) {
> > +      // The starting address could differ since we strip any suffixes beginning
> > +      // with a '.'
> > +      if (symData.startingAddress != start) {
> > +        continue;
> > +      }
> > +
> > +      if (symData.length != length) {
> >          std::ostringstream what;
> >          what << "Different lengths for the symbol "
> >               << symbol
> > -             << " (" << info[ symbol ].front().length
> > +             << " (" << symData.length
> >               << " and " << length
> >               << ")";
> >          throw rld::error( what, "SymbolTable::addSymbol" );
> > --
> > 2.27.0
>
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