llvm/include
Tobias Edler von Koch 7f80f1bbf5 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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@300205 91177308-0d34-0410-b5e6-96231b3b80d8
2017-04-13 16:24:14 +00:00
..
llvm LTO: Pass SF_Executable flag through to InputFile::Symbol 2017-04-13 16:24:14 +00:00
llvm-c Reorganize libLTO C API header lto.h (NFC) 2017-04-08 19:20:30 +00:00