LTO: Pass SF_Executable flag through to InputFile::Symbol

Summary:
The linker needs to be able to determine whether a symbol is text or data to
handle the case of a common being overridden by a strong definition in an
archive. If the archive contains a text member of the same name as the common,
that function is discarded. However, if the archive contains a data member of
the same name, that strong definition overrides the common. This is a behavior
of ld.bfd, which the Qualcomm linker also supports in LTO.

Here's a test case to illustrate:

####

cat > 1.c << \!
int blah;
!

cat > 2.c << \!
int blah() {
  return 0;
}
!

cat > 3.c << \!
int blah = 20;
!

clang -c 1.c
clang -c 2.c
clang -c 3.c

ar cr lib.a 2.o 3.o
ld 1.o lib.a -t

####

The correct output is:

1.o
(lib.a)3.o

Thanks to Shankar Easwaran and Hemant Kulkarni for the test case!

Reviewers: mehdi_amini, rafael, pcc, davide

Reviewed By: pcc

Subscribers: davide, llvm-commits, inglorion

Differential Revision: https://reviews.llvm.org/D31901

llvm-svn: 300205

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/tools/llvm-lto2/llvm-lto2.cpp b/llvm/tools/llvm-lto2/llvm-lto2.cpp
index 52ba669279c..7a8d4055338 100644
--- a/llvm/tools/llvm-lto2/llvm-lto2.cpp
+++ b/llvm/tools/llvm-lto2/llvm-lto2.cpp
@@ -317,18 +317,19 @@ static int dumpSymtab(int argc, char **argv) {
       PrintBool('I', Sym.isIndirect());
       PrintBool('O', Sym.canBeOmittedFromSymbolTable());
       PrintBool('T', Sym.isTLS());
+      PrintBool('X', Sym.isExecutable());
       outs() << ' ' << Sym.getName() << '\n';
 
       if (Sym.isCommon())
-        outs() << "        size " << Sym.getCommonSize() << " align "
+        outs() << "         size " << Sym.getCommonSize() << " align "
                << Sym.getCommonAlignment() << '\n';
 
       int Comdat = Sym.getComdatIndex();
       if (Comdat != -1)
-        outs() << "        comdat " << ComdatTable[Comdat] << '\n';
+        outs() << "         comdat " << ComdatTable[Comdat] << '\n';
 
       if (Sym.isWeak() && Sym.isIndirect())
-        outs() << "        fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
+        outs() << "         fallback " << Sym.getCOFFWeakExternalFallback() << '\n';
     }
 
     outs() << '\n';