There are ARM32's JumpTable description in ArmAsmPrinter.cpp,
but there aren't any information of AArch64's JumpTable in AArch64AsmPrinter.cpp
But,
Compiler can emit JumpTable to Binaries.
So, how does LLVM do it?
Related
I have some HDF5 C code that I am trying to port to C++Builder. I am getting this error at build time:
[ilink64 Error] Error: Unresolved external 'H5check_version' referenced from D:\DELPHITOOLS\PASHDF\C\WIN64\DEBUG\FILE2.O
H5check_version is included in H5public.h as a macro.
Why does C++Builder not find this?
H5check_version is included in H5public.h as a macro.
If that were true, you would not be getting a linker error, since macros are handled only during the preprocessor stage.
Somewhere in your project, the compiler is seeing a declaration of H5check_version as a function, and your file2 unit is calling it as a function, but the linker can't find the implementation of that function, hence the error.
Your project needs to contain a reference to the appropriate .lib file that either implements the actual function (static linking) or tells the linker which DLL the function is exported from (dynamic linking).
C/C++ is case sensitive, so H5check_version is different from H5Check_version.
AFAIK pascal is not case sensitive at all.
Regards
When we use the functions __xray_patch and __xray_unpatch, what exactly do they do? What does "patching" mean in the context of LLVM Xray?
When I use std::map's merge(source) I got an error:
error: no member named 'merge'
However, the std::map::merge should be there since c++17.
I do add set(CMAKE_CXX_STANDARD 17) and -stdlib=libc++. The std::map::extract is already there. Is this a bug in clang-7?
If I get rid of -stdlib=libc++, the gcc header does contain std::map::merge. Then I can compile. But I do need -stdlib=libc++ for my project. Any idea?
I dig around and find out that the merge neither exists in llvm/include/c++/v1/map nor in llvm/include/c++/v1/experimental/map. So which header should I include for that? Or the c++17 support in clang-7 is still problematic?
It's in LLVM 8 but not 7. It's item p0083r3 in the C++17 status table, and here's the commit:
https://github.com/llvm/llvm-project/commit/5c4e07ae5c6f7f467b436f1b24f41ef4cf9897b3
From the tag list it doesn't look like it's been back-ported to 7.
I am facing quite a strange situation trying to build a mixed-language dynamic iOS framework with Bazel.
The source code of the framework consists of *.c, *.cpp, *.m, *.mm, *.h, *.hpp files.
My first naive attempt was to declare a single objc_library rule referencing all the sources. That failed with an error message reading something about conflicting rules. Then I declared four distinct objc_library rules for *.m, *.mm, *.c, and *.cpp files respectively, and then referenced all these four rules as dependencies for the final ios_framework rule.
At this point, everything compiled and linked just fine (barring several compiler warnings which were expected). However, now the black magic begins:
The static library resulting from compiling ObjectiveC++ sources does contain all the necessary symbols (verified with the "nm" tool)
The .apple_binary_lipobin file resulting from the linking phase does not contain symbols from ObjectiveC++ sources
I believe I carefully went through the command lines used for compiling and linking, both for Bazel and xcodebuild.
The only anomalies I was able to spot:
xcodebuild passes a -single_module argument when linking, while Bazel cross tool does not.
Bazel cross tool adds '-stdlib=libc++' '-std=gnu++11' command line arguments when invoking wrapped_clang_pp during linking, while xcodebuild does not pass these arguments. I guess Bazel does this because there're these lines in the default Apple CROSSTOOL:
action_config {
config_name: "objc++-executable"
action_name: "objc++-executable"
tool {
tool_path: "wrapped_clang_pp"
execution_requirement: "requires-darwin"
}
flag_set {
flag_group {
flag: "-stdlib=libc++"
flag: "-std=gnu++11"
}
but I am not sure if these flags are really needed when invoking the linker.
I must admit I've run out of ideas except for trying to patch the CROSSTOOl file to make it behave as close as xcodebuild as possible.
Please help.
Can you try adding alwayslink = 1 to the objc_library target containing the C++ symbols? The linker is deadstripping the C++ symbols as they are not being referenced anywhere in the binary.
I am using the clang compiler on windows. I used the installer from the LLVM website. Sometimes it gives me a compiler error.
clang -I./include main.c CoreFoundation.dll
it gives:
In file included from main.c:4:
In file included from ./include\CoreFoundation/CFNumberFormatter.h:110:
./include\CoreFoundation/CFXMLParser.h:159:81: error: unknown type name 'CFXMLNodeRef'
typedef void * (*CFXMLParserCreateXMLStructureCallBack)(CFXMLParserRef parser,
CFXMLNodeRef nodeDesc, void *info);
...
and sometimes this..
In file included from main.c:4:
In file included from ./include\CoreFoundation/CoreFoundation.h:86:
./include\CoreFoundation/CFDateFormatter.h:104:105: error: unknown type name 'CFDateRef'; did you mean 'CFDataRef'?
CFStringRef CFDateFormatterCreateStringWithDate(CFAllocatorRef allocator, CFDateFormatterRef formatter, CFDateRef date) AVAILABLE_MAC_OS_X_VERSION_10_3_AND_LATER;
...
...and other similar warnings, seemingly randomly choosing where to stop. Sometimes it compiles through without error. When it gives an error, they seem to be be about not finding a symbol from an included file. It doesn't complain about not finding the file. But it doesn't consistently stop at the same point and sometimes compiles successfully.
I can reproduce this "error" under Linux with gcc. I even get the "report this compiler bug pls" message.
When it gives an error, they seem to be be about not finding a symbol from an included file
You can get this:
if you compile with multiple threads (eg. make -j8)
if you abort the compile and then start it again without "cleaning" all obj files
if you compiled your source, changed something and compile without "cleaning"
if your compiler/make/build process changes the order every time... (had this with cmake and opencv 3 source)