Change Details

I discovered that lld for darwin is generating the wrong code for lazy bindings in the __stub_helper section (at least for osx 10.12). This is the way i can reproduce this problem, using this program: #include <stdio.h> int main(int argc, char **argv) { printf("C: printf!\n"); puts("C: puts!\n"); return 0; } Then I link it using i have tested it in 3.9, 4.0 and 4.1 versions: clang -c hello.c lld -flavor darwin hello.o -o h1 -lc When i execute the binary h1 the system gives me the following error: C: printf! dyld: lazy symbol binding failed: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) dyld: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) Trace/BPT trap: 5 Investigating the code, it seems that the problem is that the asm code generated in the file StubPass.cpp, specifically in the line [[ https://github.com/llvm-mirror/lld/blob/master/lib/ReaderWriter/MachO/StubsPass.cpp#L323 | 323 ]],when it adds, what it seems an arbitrary number (12) to the offset into the lazy bind opcodes section, but it should be calculated depending on the MachONormalizedFileBinaryWrite::lazyBindingInfo result. I confirmed this bug by patching the code manually in the binary and writing the right offset in the asm code (__stub_helper). This patch fixes the content of the atom that contains the assembly code when the offset is known.

I discovered that lld for darwin is generating the wrong code for lazy bindings in the __stub_helper section (at least for osx 10.12). This is the way i can reproduce this problem, using this program: ``` #include <stdio.h> int main(int argc, char **argv) { printf("C: printf!\n"); puts("C: puts!\n"); return 0; } ``` Then I link it using i have tested it in 3.9, 4.0 and 4.1 versions: ``` $ clang -c hello.c $ lld -flavor darwin hello.o -o h1 -lc ``` When i execute the binary h1 the system gives me the following error: ``` C: printf! dyld: lazy symbol binding failed: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) dyld: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) Trace/BPT trap: 5 ``` Investigating the code, it seems that the problem is that the asm code generated in the file StubPass.cpp, specifically in the line [[ https://github.com/llvm-mirror/lld/blob/master/lib/ReaderWriter/MachO/StubsPass.cpp#L323 | 323 ]],when it adds, what it seems an arbitrary number (12) to the offset into the lazy bind opcodes section, but it should be calculated depending on the MachONormalizedFileBinaryWrite::lazyBindingInfo result. I confirmed this bug by patching the code manually in the binary and writing the right offset in the asm code (__stub_helper). This patch fixes the content of the atom that contains the assembly code when the offset is known.

I discovered that lld for darwin is generating the wrong code for lazy bindings in the __stub_helper section (at least for osx 10.12). This is the way i can reproduce this problem, using this program: ``` #include <stdio.h> int main(int argc, char **argv) { printf("C: printf!\n"); puts("C: puts!\n"); return 0; } ``` Then I link it using i have tested it in 3.9, 4.0 and 4.1 versions: ``` $ clang -c hello.c $ lld -flavor darwin hello.o -o h1 -lc ``` When i execute the binary h1 the system gives me the following error: ``` C: printf! dyld: lazy symbol binding failed: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) dyld: BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB has segment 4 which is too large (0..3) Trace/BPT trap: 5 ``` Investigating the code, it seems that the problem is that the asm code generated in the file StubPass.cpp, specifically in the line [[ https://github.com/llvm-mirror/lld/blob/master/lib/ReaderWriter/MachO/StubsPass.cpp#L323 | 323 ]],when it adds, what it seems an arbitrary number (12) to the offset into the lazy bind opcodes section, but it should be calculated depending on the MachONormalizedFileBinaryWrite::lazyBindingInfo result. I confirmed this bug by patching the code manually in the binary and writing the right offset in the asm code (__stub_helper). This patch fixes the content of the atom that contains the assembly code when the offset is known.