[LLVMbugs] [Bug 19375] New: -Os generates crashy ARM iOS binary

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=19375

            Bug ID: 19375
           Summary: -Os generates crashy ARM iOS binary
           Product: clang
           Version: 3.4
          Hardware: Macintosh
                OS: MacOS X
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: fischman at chromium.org
                CC: dgregor at apple.com, llvmbugs at cs.uiuc.edu
    Classification: Unclassified

Created attachment 12357
  --> http://llvm.org/bugs/attachment.cgi?id=12357&action=edit
tar cvjf of the pre-processed .c file and resulting .o's in question

At r189214 clang builds libvpx with -Os and the resulting binary doesn't crash.
At r191856 the resulting binary does crash.  For lots of details/noise on the
crash please see https://code.google.com/p/webrtc/issues/detail?id=3038

Since the crash is isolated to a single input .c file I've run that .c file
through clang -E under both clang versions (output differs only in immaterial
whitespace).  I then ran each of these through its respective clang -c and got
significantly different object files (though, of course, this by itself is not
a problem).  I'm attaching these files to this bug.  The relevant -E and -c
command-lines are pasted below.

FWIW this crash only manifests on iOS -Os builds; -O0 builds are fine, and
Android armv7 -Os builds are fine too.


../../third_party/llvm-build/Release+Asserts/bin/clang -MMD -MF
obj/third_party/libvpx/source/libvpx/vp8/encoder/libvpx.pickinter.o.d
-DV8_DEPRECATION_WARNINGS -DBLINK_SCALE_FILTERS_AT_RECORD_TIME -DDISABLE_NACL
-DCHROMIUM_BUILD -DUSE_LIBJPEG_TURBO=1 -DENABLE_CONFIGURATION_POLICY
-DDISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY
-DSYSTEM_NATIVELY_SIGNALS_MEMORY_PRESSURE -DENABLE_EGLIMAGE=1 -DCLD_VERSION=1
-DENABLE_SPELLCHECK=1 -DDISABLE_FTP_SUPPORT=1 -DNDEBUG -DNVALGRIND
-DDYNAMIC_ANNOTATIONS_ENABLED=0 -DNS_BLOCK_ASSERTIONS=1
-I../../third_party/libvpx/source/config/linux/arm-neon
-I../../third_party/libvpx/source/config
-I../../third_party/libvpx/source/libvpx -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
-Os -gdwarf-2 -fvisibility=hidden -Wnewline-eof -miphoneos-version-min=6.0
-arch armv7 -Wendif-labels -Wno-unused-parameter
-Wno-missing-field-initializers -Wheader-hygiene -Wno-c++11-narrowing
-Wno-char-subscripts -Wno-unneeded-internal-declaration
-Wno-covered-switch-default -Wstring-conversion -Wno-deprecated-register
-Wno-absolute-value -std=c99 -Xclang -load -Xclang
/Users/fischman/src/wr/trunk/tools/clang/scripts/../../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib
-Xclang -add-plugin -Xclang find-bad-constructs -fcolor-diagnostics
-I/Users/fischman/src/wr/trunk/third_party/libvpx/source/config/linux/arm-neon
-I/Users/fischman/src/wr/trunk/third_party/libvpx/source/config
-Igen/third_party/libvpx -Wno-unknown-warning-option  -E
../../third_party/libvpx/source/libvpx/vp8/encoder/pickinter.c -o
/tmp/b3038/libvpx.pickinter.E.189214


../../third_party/llvm-build/Release+Asserts/bin/clang -MMD -MF
obj/third_party/libvpx/source/libvpx/vp8/encoder/libvpx.pickinter.o.d
-DV8_DEPRECATION_WARNINGS -DBLINK_SCALE_FILTERS_AT_RECORD_TIME -DDISABLE_NACL
-DCHROMIUM_BUILD -DUSE_LIBJPEG_TURBO=1 -DENABLE_CONFIGURATION_POLICY
-DDISCARDABLE_MEMORY_ALWAYS_SUPPORTED_NATIVELY
-DSYSTEM_NATIVELY_SIGNALS_MEMORY_PRESSURE -DENABLE_EGLIMAGE=1 -DCLD_VERSION=1
-DENABLE_SPELLCHECK=1 -DDISABLE_FTP_SUPPORT=1 -DNDEBUG -DNVALGRIND
-DDYNAMIC_ANNOTATIONS_ENABLED=0 -DNS_BLOCK_ASSERTIONS=1
-I../../third_party/libvpx/source/config/linux/arm-neon
-I../../third_party/libvpx/source/config
-I../../third_party/libvpx/source/libvpx -isysroot
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.1.sdk
-Os -gdwarf-2 -fvisibility=hidden -Wnewline-eof -miphoneos-version-min=6.0
-arch armv7 -Wendif-labels -Wno-unused-parameter
-Wno-missing-field-initializers -Wheader-hygiene -Wno-c++11-narrowing
-Wno-char-subscripts -Wno-unneeded-internal-declaration
-Wno-covered-switch-default -Wstring-conversion -Wno-deprecated-register
-Wno-absolute-value -std=c99 -Xclang -load -Xclang
/Users/fischman/src/wr/trunk/tools/clang/scripts/../../../third_party/llvm-build/Release+Asserts/lib/libFindBadConstructs.dylib
-Xclang -add-plugin -Xclang find-bad-constructs -fcolor-diagnostics
-I/Users/fischman/src/wr/trunk/third_party/libvpx/source/config/linux/arm-neon
-I/Users/fischman/src/wr/trunk/third_party/libvpx/source/config
-Igen/third_party/libvpx -Wno-unknown-warning-option -x c -c  
/tmp/b3038/libvpx.pickinter.E.189214  -o  /tmp/b3038/libvpx.pickinter.o.189214

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