From ea50be0529c248961e1b66293f8a9e4b807294a6 Mon Sep 17 00:00:00 2001 From: Samuel Martin Date: Sun, 12 Oct 2014 10:17:23 +0200 Subject: [PATCH] core: fix x86 PIC code compilation This bug was triggered by Buildroot autobuilders [1,2], causing this kind of failures [3,4]: [ 14%] Building CXX object modules/core/CMakeFiles/opencv_core.dir/src/system.cpp.o /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp: In function '(static initializers for /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp)': /home/test/autobuild/instance-0/output/build/opencv-2.4.10/modules/core/src/system.cpp:280:10: error: inconsistent operand constraints in an 'asm' make[3]: *** [modules/core/CMakeFiles/opencv_core.dir/src/system.cpp.o] Error 1 [1] http://buildroot.org/ [2] http://autobuild.buildroot.org/ [3] http://autobuild.buildroot.org/?reason=opencv-2.4.10 [4] http://autobuild.buildroot.org/results/483/4838285b25d6293a5cf0bb9eadd5040a7c75d766/build-end.log Signed-off-by: Samuel Martin --- modules/core/src/system.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/modules/core/src/system.cpp b/modules/core/src/system.cpp index 5a970d5..e9ffdc7 100644 --- a/modules/core/src/system.cpp +++ b/modules/core/src/system.cpp @@ -267,14 +267,17 @@ struct HWFeatures : "cc" ); #else + // We need to preserve ebx since we are compiling PIC code. + // This means we cannot use "=b" for the 2nd output register. asm volatile ( "pushl %%ebx\n\t" "movl $7,%%eax\n\t" "movl $0,%%ecx\n\t" "cpuid\n\t" + "movl %%ebx,%1\n\t" "popl %%ebx\n\t" - : "=a"(cpuid_data[0]), "=b"(cpuid_data[1]), "=c"(cpuid_data[2]), "=d"(cpuid_data[3]) + : "=a"(cpuid_data[0]), "=r"(cpuid_data[1]), "=c"(cpuid_data[2]), "=d"(cpuid_data[3]) : : "cc" );