commit ac8b85009855899ae8daf1ba40e2447a904b8305
author Tom Stellard <tstellar@redhat.com> Tue Dec 05 20:25:50 2017 +0000
committer Tom Stellard <tstellar@redhat.com> Tue Dec 05 20:25:50 2017 +0000
tree 8f9317998e29c24970ad67cc9e401a85cfdf0bc5
parent 3fb6bd21ad5688d0564048dd593c986c10a2783c

Merging r311734:

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r311734 | ruiu | 2017-08-24 16:51:40 -0700 (Thu, 24 Aug 2017) | 44 lines

[MACH-O] Fix the ASM code generated for __stub_helpers section

Patch by Patricio Villalobos.

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 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.

Differential Revision: https://reviews.llvm.org/D35387
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git-svn-id: https://llvm.org/svn/llvm-project/lld/branches/release_50@319825 91177308-0d34-0410-b5e6-96231b3b80d8