https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65264
Bug ID: 65264
Summary: compare debug failure when using stdin
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: debug
Assignee: unassigned at gcc dot gnu.org
Reporter: trippels at gcc dot gnu.org
Building a Linux kernel on ppc64 with GCC_COMPARE_DEBUG=1 fails:
...
LD init/built-in.o
arch/powerpc/platforms/built-in.o(.toc+0x5e8): error: undefined reference to
'opal_tracepoint_refcount'
arch/powerpc/platforms/built-in.o(.toc+0x648): error: undefined reference to
'hcall_tracepoint_refcount'
arch/powerpc/platforms/built-in.o(__jump_table+0x10): error: undefined
reference to 'opal_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x28): error: undefined
reference to 'opal_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x40): error: undefined
reference to 'opal_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x58): error: undefined
reference to 'opal_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x8b0): error: undefined
reference to 'hcall_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x8c8): error: undefined
reference to 'hcall_tracepoint_key'
arch/powerpc/platforms/built-in.o(__jump_table+0x8e0): error: undefined
reference to 'hcall_tracepoint_key'
Makefile:914: recipe for target 'vmlinux' failed
make: *** [vmlinux] Error 1
This happens because the kernel Makefile contains:
779 # check for 'asm goto'
780 ifeq ($(shell $(CONFIG_SHELL) $(srctree)/scripts/gcc-goto.sh $(CC)), y)
781 KBUILD_CFLAGS += -DCC_HAVE_ASM_GOTO
782 endif
markus@x4 linux % cat scripts/gcc-goto.sh
#!/bin/sh
# Test for gcc 'asm goto' support
# Copyright (C) 2010, Jason Baron <jba...@redhat.com>
cat << "END" | $@ -x c - -c -o /dev/null >/dev/null 2>&1 && echo "y"
int main(void)
{
#if defined(__arm__) || defined(__aarch64__)
/*
* Not related to asm goto, but used by jump label
* and broken on some ARM GCC versions (see GCC Bug 48637).
*/
static struct { int dummy; int state; } tp;
asm (".long %c0" :: "i" (&tp.state));
#endif
entry:
asm goto ("" :::: entry);
return 0;
}
END
This test always fails with GCC_COMPARE_DEBUG=1.
markus@x4 linux % echo "int main () {}" | gcc -x c - -c -o /dev/null
markus@x4 linux % echo "int main () {}" | GCC_COMPARE_DEBUG=1 gcc -x c - -c -o
/dev/null
gcc: error: -: -fcompare-debug failure (length)
