http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54170
Bug #: 54170
Summary: Call to lambda elided
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: [email protected]
ReportedBy: [email protected]
Created attachment 27935
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27935
preprocessed source
gcc version: 4.7.0
target: mingw32
Configured with: ../gcc-4.7.0/configure
--enable-languages=c,c++,ada,fortran,objc,obj-c++ --disable-sjlj-exceptions
--with-dwarf2 --enable-shared --enable-libgomp --disable-win32-registry
--enable-libstdcxx-debug --disable-build-poststage1-with-cxx
--enable-version-specific-runtime-libs --build=mingw32 --prefix=/mingw
command line: gcc -v -save-temps -std=gnu++0x -c -g src\lambdatest.cpp
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-std=gnu++11' '-c' '-g' '-mtune=i386'
'-march=i386'
lambdatest.cpp:
#include <utility> // for std::forward
// externally defined
void ExternalFunction1(const char*, int);
void ExternalFunction2(int, void**);
template <class Callable, typename... ArgTypes>
void* Call(Callable native_func, ArgTypes&&... args) noexcept
{
return native_func(std::forward<ArgTypes>(args)...);
}
void* test_lambda(void* functionData, int argc, void* argv[])
{
return Call([=]
{
ExternalFunction1("Lalala...", 0);
ExternalFunction2(argc, argv);
return nullptr;
});
}
---
This compiles without error messages, but gives incorrect output. The call to
native_func on line 10 is left out, and Call simply returns 0 instead. This
can be verified by examining the generated assembly:
__Z4CallIZ11test_lambdaPviPS0_EUlvE_IEES0_T_DpOT0_:
pushl %ebp
movl %esp, %ebp
movl $0, %eax
popl %ebp
ret
No code is generated for the lambda body, and the resulting object file does
not contain references to ExternalFunction1 or ExternalFunction2.
