http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60151
Bug ID: 60151
Summary: HAVE_AS_GOTOFF_IN_DATA is mis-detected on x86-64
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: hjl.tools at gmail dot com
CC: ubizjak at gmail dot com
i386.h has
/* Under some conditions we need jump tables in the text section,
because the assembler cannot handle label differences between
sections. This is the case for x86_64 on Mach-O for example. */
#define JUMP_TABLES_IN_TEXT_SECTION \
(flag_pic && ((TARGET_MACHO && TARGET_64BIT) \
|| (!TARGET_64BIT && !HAVE_AS_GOTOFF_IN_DATA)))
HAVE_AS_GOTOFF_IN_DATA is only used for 32-bit PIC. However,
configure.ac has
gcc_GAS_CHECK_FEATURE([GOTOFF in data],
gcc_cv_as_ix86_gotoff_in_data, [2,11,0],,
[ .text
.L0:
nop
.data
.long .L0@GOTOFF])
AC_DEFINE_UNQUOTED(HAVE_AS_GOTOFF_IN_DATA,
On Linux/x86-64, we get
configure:25031: checking assembler for GOTOFF in data
configure:25048: /usr/local/bin/as --64 -o conftest.o conftest.s >&5
conftest.s: Assembler messages:
conftest.s:5: Error: 8-byte relocation cannot be applied to 4-byte field
configure:25051: $? = 1
configure: failed program was
.text
.L0:
nop
.data
.long .L0@GOTOFF
configure:25062: result: no
On Linux/i686, we get
configure:25026: checking assembler for GOTOFF in data
configure:25043: /usr/local32/bin/as --32 -o conftest.o conftest.s >&5
configure:25046: $? = 0
configure:25057: result: yes
As the result, we put jump table in .text section for -m32 -fPIC
on Linux/x86-64.
