[LLVMbugs] [Bug 10038] New: clang++ generates HIDDEN symbols where g++ doesn't

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=10038

           Summary: clang++ generates HIDDEN symbols where g++ doesn't
           Product: clang
           Version: trunk
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: -New Bugs
        AssignedTo: unassignedclangbugs at nondot.org
        ReportedBy: fischman at chromium.org
                CC: llvmbugs at cs.uiuc.edu


Created an attachment (id=6661)
 --> (http://llvm.org/bugs/attachment.cgi?id=6661)
repro case for clang++/g++ differenc

For the attached source file, I get this:

$ clang++ -c -fvisibility-inlines-hidden -fvisibility=hidden visibility.cc &&
readelf -Ws visibility.o |c++filt |fgrep 'std::basic_string<unsigned short,
base::string16_char_traits, std::allocator<unsigned short> >::insert(unsigned
long, unsigned short const*)' && g++ -c -fvisibility-inlines-hidden
-fvisibility=hidden visibility.cc && readelf -Ws visibility.o |c++filt |fgrep
'std::basic_string<unsigned short, base::string16_char_traits,
std::allocator<unsigned short> >::insert(unsigned long, unsigned short const*)'
  630: 0000000000000000    79 FUNC    WEAK   HIDDEN  458
std::basic_string<unsigned short, base::string16_char_traits,
std::allocator<unsigned short> >::insert(unsigned long, unsigned short const*)
  582: 0000000000000000    66 FUNC    WEAK   DEFAULT  399
std::basic_string<unsigned short, base::string16_char_traits,
std::allocator<unsigned short> >::insert(unsigned long, unsigned short const*)

Note that whereas clang++ generates a HIDDEN symbol, g++ generates a DEFAULT
(public) symbol.  What's up with that?

(note that both -fvisibility-inlines-hidden -fvisibility=hidden are specified;
if only one is specified then different symbols in std::basic_string are
DEFAULT or HIDDEN, depending on whether they got inlined or not).

This came up in the context of making chromium's component=shared_library build
work with clang (it works fine w/ gcc).  For details on this build style see
https://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thread/846e33b3952f726/80ca2a622a05ed85#

Version info: this is all on a lucid ubuntu box and:
clang version 3.0 (trunk 131935)
Target: x86_64-unknown-linux-gnu
Thread model: posix
and:
g++ (Ubuntu 4.4.3-4ubuntu5) 4.4.3

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