Errors with Clang in C++11 mode

[huhlig]

/root/llvm/src/ldc/dmd2/func.c:540:18: error: case value evaluates to -2, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -2: // can't determine because of fwd refs
^
/root/llvm/src/ldc/dmd2/func.c:503:18: error: case value evaluates to -1, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -1:
^
/root/llvm/src/ldc/dmd2/func.c:632:22: error: case value evaluates to -2, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -2:
^
/root/llvm/src/ldc/dmd2/func.c:629:22: error: case value evaluates to -1, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -1:
^
4 errors generated.
make[2]: *** [CMakeFiles/LDCShared.dir/dmd2/func.c.o] Error 1

[huhlig]

[ 0%] Building CXX object CMakeFiles/LDCShared.dir/dmd2/func.c.o
/usr/local/bin/clang++ -DDMDV2 -DIN_LLVM -DOPAQUE_VTBLS -DLDC_INSTALL_PREFIX="/usr/local" -DLDC_LLVM_VER=303 -DLDC_LLVM_VERSION_STRING="3.3svn" -DPOSIX -DUSE_METADATA -D__LITTLE_ENDIAN__ -DLLVM_INTRINSIC_TD_PATH="/usr/local/include" -DHAVE_SC_ARG_MAX -I/root/llvm/src/ldc/. -I/root/llvm/src/ldc/dmd2 -I/root/llvm/src/ldc/dmd2/root -I/root/llvm/build/ldc/dmd2 -I/root/llvm/src/ldc -I/usr/local/include -I/usr/local/include -D_DEBUG -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS -O3 -fomit-frame-pointer -std=c++11 -fvisibility-inlines-hidden -fno-exceptions -fno-rtti -fPIC -Woverloaded-virtual -Wcast-qual -fexceptions -w -o CMakeFiles/LDCShared.dir/dmd2/func.c.o -c /root/llvm/src/ldc/dmd2/func.c
/root/llvm/src/ldc/dmd2/func.c:540:18: error: case value evaluates to -2, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -2: // can't determine because of fwd refs
^
/root/llvm/src/ldc/dmd2/func.c:503:18: error: case value evaluates to -1, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -1:
^
/root/llvm/src/ldc/dmd2/func.c:632:22: error: case value evaluates to -2, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -2:
^
/root/llvm/src/ldc/dmd2/func.c:629:22: error: case value evaluates to -1, which cannot be narrowed to type 'size_t' (aka 'unsigned long') [-Wc++11-narrowing]
case -1:
^
4 errors generated.
make[2]: *** [CMakeFiles/LDCShared.dir/dmd2/func.c.o] Error 1

[redstar]

I never tried it but I can imagine that the DMD source is not C++11 compatible. Did you try to compile LDC without -Wc++11-narrowing? In general, LDC compiles with clang.

[huhlig]

I'm only using the default clang settings. Not adding anything special.

[huhlig]

Build Script below

rm -Rf ~/llvm
mkdir -p ~/llvm/build/llvm ~/llvm/build/ldc ~/llvm/build/lldb
svn co http://llvm.org/svn/llvm-project/llvm/trunk ~/llvm/src/llvm
svn co http://llvm.org/svn/llvm-project/lldb/trunk ~/llvm/src/llvm/tools/lldb
svn co http://llvm.org/svn/llvm-project/cfe/trunk ~/llvm/src/llvm/tools/clang
svn co http://llvm.org/svn/llvm-project/clang-tools-extra/trunk ~/llvm/src/llvm/tools/clang/tools/extra
svn co http://llvm.org/svn/llvm-project/compiler-rt/trunk ~/llvm/src/llvm/projects/compiler-rt
git clone --recursive http://github.com/ldc-developers/ldc.git ~/llvm/src/ldc
(cd ~/llvm/build/llvm && ~/llvm/src/llvm/configure --enable-optimized --enable-doxygen --enable-cxx11 && make && make install)
export CC=clang
export CXX=clang++
(cd ~/llvm/build/ldc && cmake ~/llvm/src/ldc && make && make install)

[huhlig]

Side note: "case value evaluates to -2, which cannot be narrowed to type 'size_t' " Why is the input an unsigned value and the case is negative... that seems very naughty.

[dnadlinger]

Ah, so the C++11 option is leaking in from the LLVM CFLAGS? I think the best thing to do would just be to fix the DMD source.

Regarding -1/-2, DMD uses such "special" unsigned values (i.e. size_t.max, size_t.max - 1, …) quite liberally.

[dnadlinger]

@huhlig: To test my hypothesis, could you please run llvm-config --cxxflags?

[dnadlinger]

This is an upstream problem, the DMD source does not compile with Clang and C++11 enabled yet.

[redstar]

I am closing this issue because LDC can now be compiled with -std=c++11.