Hi William, On Tue, Dec 8, 2015 at 8:00 PM, William Dillon via swift-dev < swift-dev@swift.org> wrote:
> Hi all, > > I’ve been working on trying to get Swift to compile on ARMv7 (armv7l > specifically, not sure if other variants will work as well). I’ve gotten > pretty far, but I ran a cross an issue that has me a little confused. For > convenience, here’s the bug that has some of my messages in the comments: > https://bugs.swift.org/browse/SR-40 and here’s my Github fork if you want > to play along at home: https://github.com/hpux735/swift By the way, I’m > compiling on an Nvidia tegra TK2 development board with 2GB of ram and a > 25GB swapfile on an external SSD. This brings native compile times down to > reasonable levels. I was compiling on the BeagleBone Black formerly, and > that was painful (like over a day for LLVM). > > So far, cmark and llvm compile just fine (no surprise there), and swift > gets pretty far along. The weird issue, which will certainly expose my > weakness in C++ and large build systems, is that the swift_ssize_t doesn’t > match ssize_t. > > [6/61] Building CXX object > stdlib/public/stubs/CMakeFiles/swiftStdlibStubs-linux-armv7.dir/Stubs.cpp.o > FAILED: /usr/bin/clang++ -DGTEST_HAS_RTTI=0 -D_DEBUG > -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS > -fno-stack-protector -fPIC -fvisibility-inlines-hidden -Wall -W > -Wno-unused-parameter -Wwrite-strings -Wcast-qual > -Wmissing-field-initializers -Wcovered-switch-default -Wnon-virtual-dtor > -Werror=date-time -std=c++11 -fcolor-diagnostics -ffunction-sections > -fdata-sections -Wdocumentation -Wimplicit-fallthrough -Wunreachable-code > -Woverloaded-virtual -O3 -Istdlib/public/stubs > -I/home/wdillon/swift/stdlib/public/stubs -I/home/wdillon/swift/include > -Iinclude > -I/home/wdillon/build/Ninja-ReleaseAssert/llvm-linux-armv7/include > -I/home/wdillon/llvm/include > -I/home/wdillon/build/Ninja-ReleaseAssert/llvm-linux-armv7/tools/clang/include > -I/home/wdillon/llvm/tools/clang/include -I/home/wdillon/cmark/src > -I/home/wdillon/build/Ninja-ReleaseAssert/cmark-linux-armv7/src -UNDEBUG > -fno-exceptions -fno-rtti -Wglobal-constructors -Wexit-time-destructors > -target arm-unknown-linux-gnueabihf -isysroot / -O2 -g0 -UNDEBUG -MMD -MT > stdlib/public/stubs/CMakeFiles/swiftStdlibStubs-linux-armv7.dir/LibcShims.cpp.o > -MF > "stdlib/public/stubs/CMakeFiles/swiftStdlibStubs-linux-armv7.dir/LibcShims.cpp.o.d" > -o > stdlib/public/stubs/CMakeFiles/swiftStdlibStubs-linux-armv7.dir/LibcShims.cpp.o > -c /home/wdillon/swift/stdlib/public/stubs/LibcShims.cpp > /home/wdillon/swift/stdlib/public/stubs/LibcShims.cpp:24:1: error: > static_assert failed "__swift_ssize_t is wrong" > static_assert(std::is_same<ssize_t, swift::__swift_ssize_t>::value, > ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > 1 error generated. > > Now, the sizes match (4 bytes each), but the std::is_same() function says > no. I grep’d the clang codebase for the definition of ssize_t, and it > seems like it’s a ‘long’ whereas the swift_ssize_t is a 'long int’. > 'long' and 'long int' are the same type. Try preprocessing the following program with 'clang -E' and check how the type is defined: #include <unistd.h> #include <sys/types.h> > I looked into the LibcShims a bit, and the expectation is that the > definition in the header is not universally correct, and will be checked: > > // This declaration is not universally correct. We verify its correctness > for > // the current platform in the runtime code. > typedef long int __swift_ssize_t; > > And it is thusly (in LibcShims.cpp): > > static_assert(std::is_same<ssize_t, swift::__swift_ssize_t>::value, > "__swift_ssize_t is wrong”); > > What’s less clear is the mechanism with which I am to change this > definition in a way that doesn’t mess-up other platforms. > > Use #if: #if defined(__linux__) && defined(__arm__) ... #else ... #endif To find the specific macro names to check for, dump the predefines buffer and find an appropriate one (although I think __linux__ and __arm__ are correct): echo "" | clang -x c++ -std=c++11 - -dM -E Dmitri -- main(i,j){for(i=2;;i++){for(j=2;j<i;j++){if(!(i%j)){j=0;break;}}if (j){printf("%d\n",i);}}} /*Dmitri Gribenko <griboz...@gmail.com>*/
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