[llvm-commits] [llvm] r141579 - in /llvm/trunk: include/llvm/Support/Format.h test/Object/objdump-sectionheaders.test tools/llvm-objdump/llvm-objdump.cpp

[Dimitry Andric]

On 2011-10-10 23:21, Nick Lewycky wrote:
> Author: nicholas
> Date: Mon Oct 10 16:21:34 2011
> New Revision: 141579
>
> URL: http://llvm.org/viewvc/llvm-project?rev=141579&view=rev
> Log:
> Add support for dumping section headers to llvm-objdump. This uses the same
> flags as binutils objdump but the output is different, not just in format but
> also showing different sections. Compare its results against readelf, not
> objdump.
>
> Added:
>      llvm/trunk/test/Object/objdump-sectionheaders.test
> Modified:
>      llvm/trunk/include/llvm/Support/Format.h
>      llvm/trunk/tools/llvm-objdump/llvm-objdump.cpp
>

This makes the Object/objdump-sectionheaders.test fail on i386:

   ...
   FAIL: LLVM :: Object/objdump-sectionheaders.test (3835 of 5635)
   ******************** TEST 'LLVM :: Object/objdump-sectionheaders.test' FAILED ********************
   Script:
   --
   llvm-objdump -h /home/dim/src/llvm/trunk/test/Object/TestObjectFiles/trivial-object-test.elf-x86-64               | /home/dim/obj/llvm-1/Release+Asserts/bin/FileCheck /home/dim/src/llvm/trunk/test/Object/objdump-sectionheaders.test
   --
   Exit Code: 1
   Command Output (stderr):
   --
   Stack dump:
   0.      Program arguments: llvm-objdump -h /home/dim/src/llvm/trunk/test/Object/TestObjectFiles/trivial-object-test.elf-x86-64
   FileCheck error: '-' is empty.
   --

The cause is an llvm-objdump segfault:

   $ ~/obj/llvm-1/Release+Asserts/bin/llvm-objdump -h /home/dim/src/llvm/trunk/test/Object/TestObjectFiles/trivial-object-test.elf-x86-64
   Sections:
   Idx Name          Size      Address          Type
     0               000000000 00000000000000000 (null)
     1 .text         000000026 00000000000000000 (null)
   Stack dump:
   0.      Program arguments: /home/dim/obj/llvm-1/Release+Asserts/bin/llvm-objdump -h /home/dim/src/llvm/trunk/test/Object/TestObjectFiles/trivial-object-test.elf-x86-64
   Segmentation fault: 11 (core dumped)

The segfault occurs in tools/llvm-objdump/llvm-objdump.cpp:

...
static void PrintSectionHeaders(const ObjectFile *o) {
..
     uint64_t Address;
     if (error(si->getAddress(Address))) return;
     uint64_t Size;
...
     outs() << format("%3d %-13s %09x %017x %s\n", i, Name.str().c_str(), Size,
                      Address, Type.c_str());

Size and Address are both 64-bit variables, but they are snprintf'd
using %x, which leads to a segfault on i386.  I have attached a fix for
this.

Unfortunately, the format() functions in include/llvm/Support/Format.h
cannot have an __attribute__((format(printf(1,2)) appended, since that
attribute works only on variadic functions, which is a real pity.  There
may be many more of these format problems... :)
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