LD: Always make a SEGMENT_START expression section-relative

Fix an issue with the SEGMENT_START builtin function where its result is
absolute when taken from the default supplied, and section-relative when
taken from a `-T' command-line override.  This is against documentation,
inconsistent and unexpected, and with PIE executables gives an incorrect
result with the `__executable_start' symbol.

Make the result of SEGMENT_START always section-relative then.

	ld/
	* ldexp.c (fold_binary): Always make the result of SEGMENT_START
	section-relative.
	* testsuite/ld-scripts/segment-start.d: New test.
	* testsuite/ld-scripts/segment-start.ld: New test linker script.
	* testsuite/ld-scripts/segment-start.s: New test source.
	* testsuite/ld-scripts/script.exp: Run the new test.
This commit is contained in:
Maciej W. Rozycki 2018-09-14 20:22:56 +01:00 committed by Maciej W. Rozycki
parent a000f8817b
commit 6057dc97e4
6 changed files with 50 additions and 1 deletions

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@ -1,3 +1,13 @@
2018-09-14 Maciej W. Rozycki <macro@mips.com>
Maciej W. Rozycki <macro@linux-mips.org>
* ldexp.c (fold_binary): Always make the result of SEGMENT_START
section-relative.
* testsuite/ld-scripts/segment-start.d: New test.
* testsuite/ld-scripts/segment-start.ld: New test linker script.
* testsuite/ld-scripts/segment-start.s: New test source.
* testsuite/ld-scripts/script.exp: Run the new test.
2018-09-14 Maciej W. Rozycki <macro@linux-mips.org>
* ldexp.c (fold_binary): Check that `config.maxpagesize' is

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@ -534,6 +534,7 @@ fold_binary (etree_type *tree)
operand, binary.rhs is first operand. */
if (expld.result.valid_p && tree->type.node_code == SEGMENT_START)
{
bfd_vma value = expld.result.value;
const char *segment_name;
segment_type *seg;
@ -551,9 +552,10 @@ fold_binary (etree_type *tree)
"isn't multiple of maximum page size\n"),
segment_name);
seg->used = TRUE;
new_rel_from_abs (seg->value);
value = seg->value;
break;
}
new_rel_from_abs (value);
return;
}

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@ -231,3 +231,7 @@ foreach test_script $test_script_list {
run_dump_test "align-with-input"
run_dump_test "pr20302"
run_dump_test "segment-start" {{name (default)}}
run_dump_test "segment-start" {{name (overridden)} \
{ld -Ttext-segment=0x10000000}}

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@ -0,0 +1,19 @@
#PROG: nm
#name: SEGMENT_START expression not absolute
#source: segment-start.s
#ld: -e 0 -u __executable_start -T segment-start.ld
#xfail: mmix-*-* pdp11-*-* powerpc-*-aix* powerpc-*-beos* rs6000-*-* sh-*-pe
#xfail: c30-*-*aout* tic30-*-*aout* c54x*-*-*coff* tic54x-*-*coff*
# XFAIL targets that are not expected to handle SEGMENT_START correctly.
# Make sure `__executable_start' is regular:
#
# 10000000 T __executable_start
#
# not absolute:
#
# 10000000 A __executable_start
#...
0*10000000 T __executable_start
#pass

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@ -0,0 +1,12 @@
SECTIONS
{
PROVIDE (__executable_start = SEGMENT_START ("text-segment", 0x10000000));
.text : { *(.text) }
.data : { *(.data) }
.bss : { *(.bss) }
.loader : { *(.loader) }
.symtab : { *(.symtab) }
.strtab : { *(.strtab) }
.shstrtab : { *(.shstrtab) }
/DISCARD/ : { *(*) }
}

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@ -0,0 +1,2 @@
.text
.space 16