[PATCH] [Compiler-rt][Sanitizer][MSan][i386] Adding support for i386

[Mohit Bhakkad]

Update:

- Thanks @eugenis, issue with i386 support is resolved.



- Right now, while testing msan32 using lit, most of the tests are failing with:



  FATAL: Code 0x5556aec0 is out of application range. Non-PIE build?
  FATAL: MemorySanitizer can not mmap the shadow memory.
  FATAL: Make sure to compile with -fPIE and to link with -pie.
  FATAL: Disabling ASLR is known to cause this error.
  FATAL: If running under GDB, try 'set disable-randomization off'.
  ==23092==Process memory map follows:
  	0x55555000-0x555ed000	/home/mohit/compiler-rt_build/test/msan/Output/strlen_of_shadow.cc.tmp
  	0x555ed000-0x555ee000	/home/mohit/compiler-rt_build/test/msan/Output/strlen_of_shadow.cc.tmp
  	0x555ee000-0x555f1000	/home/mohit/compiler-rt_build/test/msan/Output/strlen_of_shadow.cc.tmp
  	0x555f1000-0x56648000	
  	0x56648000-0x56668000	/lib/i386-linux-gnu/ld-2.19.so
  	0x56668000-0x56669000	/lib/i386-linux-gnu/ld-2.19.so
  	0x56669000-0x5666a000	/lib/i386-linux-gnu/ld-2.19.so
  	0x5666a000-0x5666b000	[vdso]
  	0x5666b000-0x56672000	
  	0x5668c000-0x56768000	/usr/lib/i386-linux-gnu/libstdc++.so.6.0.19
  	0x56768000-0x56769000	/usr/lib/i386-linux-gnu/libstdc++.so.6.0.19
  	0x56769000-0x5676d000	/usr/lib/i386-linux-gnu/libstdc++.so.6.0.19
  	0x5676d000-0x5676e000	/usr/lib/i386-linux-gnu/libstdc++.so.6.0.19
  	0x5676e000-0x56775000	
  	0x56775000-0x567b9000	/lib/i386-linux-gnu/libm-2.19.so
  	0x567b9000-0x567ba000	/lib/i386-linux-gnu/libm-2.19.so
  	0x567ba000-0x567bb000	/lib/i386-linux-gnu/libm-2.19.so
  	0x567bb000-0x567bc000	
  	0x567bc000-0x567d4000	/lib/i386-linux-gnu/libpthread-2.19.so
  	0x567d4000-0x567d5000	/lib/i386-linux-gnu/libpthread-2.19.so
  	0x567d5000-0x567d6000	/lib/i386-linux-gnu/libpthread-2.19.so
  	0x567d6000-0x567d8000	
  	0x567d8000-0x567df000	/lib/i386-linux-gnu/librt-2.19.so
  	0x567df000-0x567e0000	/lib/i386-linux-gnu/librt-2.19.so
  	0x567e0000-0x567e1000	/lib/i386-linux-gnu/librt-2.19.so
  	0x567e1000-0x567e4000	/lib/i386-linux-gnu/libdl-2.19.so
  	0x567e4000-0x567e5000	/lib/i386-linux-gnu/libdl-2.19.so
  	0x567e5000-0x567e6000	/lib/i386-linux-gnu/libdl-2.19.so
  	0x567e6000-0x56802000	/lib/i386-linux-gnu/libgcc_s.so.1
  	0x56802000-0x56803000	/lib/i386-linux-gnu/libgcc_s.so.1
  	0x56803000-0x569ac000	/lib/i386-linux-gnu/libc-2.19.so
  	0x569ac000-0x569ae000	/lib/i386-linux-gnu/libc-2.19.so
  	0x569ae000-0x569af000	/lib/i386-linux-gnu/libc-2.19.so
  	0x569af000-0x56b5f000	
  	0xffac2000-0xffae3000	[stack]
  ==23092==End of process memory map.

but when I run tests individually, almost all tests are giving expected o/p:
for eg:(see that I have used exact options that of in lit suite)

  mohit at mohit:~$ /home/mohit/LLVM_x86/install/bin/clang --driver-mode=g++ -fsanitize=memory -mno-omit-leaf-frame-pointer -fno-omit-frame-pointer -fno-optimize-sibling-calls  -gline-tables-only -m32 -fsanitize-memory-track-origins=2  -O3 /home/mohit/compiler-rt/test/msan/chained_origin.cc
  mohit at mohit:~$ ./a.out 
  ==23140== WARNING: MemorySanitizer: use-of-uninitialized-value
      #0 0xf77b17dd in main /home/mohit/compiler-rt/test/msan/chained_origin.cc:47:3
      #1 0xf73e6a82 in __libc_start_main (/lib/i386-linux-gnu/libc.so.6+0x19a82)
      #2 0xf774be95 in _start (/home/mohit/a.out+0x14e95)
  
    Uninitialized value was stored to memory at
      #0 0xf77b1722 in fn_h() /home/mohit/compiler-rt/test/msan/chained_origin.cc:35:5
      #1 0xf77b17a2 in main /home/mohit/compiler-rt/test/msan/chained_origin.cc:46:3
      #2 0xf73e6a82 in __libc_start_main (/lib/i386-linux-gnu/libc.so.6+0x19a82)
  
    Uninitialized value was stored to memory at
      #0 0xf77b1692 in fn_g(int) /home/mohit/compiler-rt/test/msan/chained_origin.cc:25:5
      #1 0xf77b16bb in fn_f(int) /home/mohit/compiler-rt/test/msan/chained_origin.cc:30:3
      #2 0xf77b179d in main /home/mohit/compiler-rt/test/msan/chained_origin.cc:45:3
      #3 0xf73e6a82 in __libc_start_main (/lib/i386-linux-gnu/libc.so.6+0x19a82)
  
    Uninitialized value was created by an allocation of 'z' in the stack frame of function 'main'
      #0 0xf77b1730 in main /home/mohit/compiler-rt/test/msan/chained_origin.cc:38
  
  SUMMARY: MemorySanitizer: use-of-uninitialized-value /home/mohit/compiler-rt/test/msan/chained_origin.cc:47 main
  Exiting

I am pretty sure about the correctness of address ranges in this patch. It looks like it is failing some check, investigating it now.

**tl;dr: most of the test cases are passing individually, but with lit test suite, almost all are failing due to conflict in addresses.**


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http://reviews.llvm.org/D6433

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