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[Bug c++/65062] New: [4.9 Regression] Miscompilation: invalid C++ mangled name for global variable
- From: "thiago at kde dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Sat, 14 Feb 2015 02:44:35 +0000
- Subject: [Bug c++/65062] New: [4.9 Regression] Miscompilation: invalid C++ mangled name for global variable
- Auto-submitted: auto-generated
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65062
Bug ID: 65062
Summary: [4.9 Regression] Miscompilation: invalid C++ mangled
name for global variable
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: thiago at kde dot org
Code:
template <class>
void tf()
{
extern void (*qt_memfill32)();
qt_memfill32();
}
void f() {
tf<int>();
}
When compiled with GCC 5.0, the object file has a reference to
"_Z12qt_memfill32", which doesn't seem to me to be a valid C++ mangled name. At
the very least, it's an ABI compatibility break with previous versions of GCC,
other compilers and with itself.
This symbol is defined in another .o as "qt_memfill32", even when compiled with
GCC 5.0.
Tests:
gcc-5.0 -O2 -S -o - test.cpp:
jmp *_Z12qt_memfill32(%rip)
gcc-4.9 -O2 -S -o - test.cpp:
movq qt_memfill32(%rip), %rax
jmp *%rax
clang-3.6 -O2 -S -o - test.cpp:
jmpq *qt_memfill32(%rip) # TAILCALL
icpc -O2 -S -o - test.cpp:
movq qt_memfill32(%rip), %rax
jmp *%rax