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MIPS/GAS: Correct branch relaxation for weak symbols

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Weak symbols can be preempted at link time so always choose the longer
sequence in branch relaxation, according to the relaxation level chosen,
so that any symbol finally used as the branch target is reachable.

2016-04-13  Maciej W. Rozycki  <macro@imgtec.com>
            Andrew Bennett  <andrew.bennett@imgtec.com>

	gas/
	* config/tc-mips.c (relaxed_branch_length): Use the long
	sequence where the target is a weak symbol.
	(relaxed_micromips_32bit_branch_length): Likewise.
	(relaxed_micromips_16bit_branch_length): Likewise.
	* testsuite/gas/mips/branch-weak-1.d: New test.
	* testsuite/gas/mips/branch-weak-2.d: New test.
	* testsuite/gas/mips/branch-weak-3.d: New test.
	* testsuite/gas/mips/branch-weak-4.d: New test.
	* testsuite/gas/mips/branch-weak-5.d: New test.
	* testsuite/gas/mips/branch-weak.l: New stderr output.
	* testsuite/gas/mips/branch-weak.s: New test source.
	* testsuite/gas/mips/mips.exp: Run the new tests.
This commit is contained in:
Maciej W. Rozycki 2016-04-09 11:59:36 +01:00
parent c1f61bd2b0
commit 991f40a9fa
10 changed files with 122 additions and 0 deletions
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16
gas/ChangeLog
View file

@ -1,3 +1,19 @@
2016-04-13 Maciej W. Rozycki <macro@imgtec.com>
Andrew Bennett <andrew.bennett@imgtec.com>
* config/tc-mips.c (relaxed_branch_length): Use the long
sequence where the target is a weak symbol.
(relaxed_micromips_32bit_branch_length): Likewise.
(relaxed_micromips_16bit_branch_length): Likewise.
* testsuite/gas/mips/branch-weak-1.d: New test.
* testsuite/gas/mips/branch-weak-2.d: New test.
* testsuite/gas/mips/branch-weak-3.d: New test.
* testsuite/gas/mips/branch-weak-4.d: New test.
* testsuite/gas/mips/branch-weak-5.d: New test.
* testsuite/gas/mips/branch-weak.l: New stderr output.
* testsuite/gas/mips/branch-weak.s: New test source.
* testsuite/gas/mips/mips.exp: Run the new tests.
2016-04-13 Maciej W. Rozycki <macro@imgtec.com>
* config/tc-mips.c (relaxed_branch_length): Use the long

3
gas/config/tc-mips.c
View file

@ -16798,6 +16798,7 @@ relaxed_branch_length (fragS *fragp, asection *sec, int update)
if (fragp
&& S_IS_DEFINED (fragp->fr_symbol)
&& !S_IS_WEAK (fragp->fr_symbol)
&& sec == S_GET_SEGMENT (fragp->fr_symbol))
{
addressT addr;
@ -16861,6 +16862,7 @@ relaxed_micromips_32bit_branch_length (fragS *fragp, asection *sec, int update)
if (fragp
&& S_IS_DEFINED (fragp->fr_symbol)
&& !S_IS_WEAK (fragp->fr_symbol)
&& sec == S_GET_SEGMENT (fragp->fr_symbol))
{
addressT addr;
@ -16952,6 +16954,7 @@ relaxed_micromips_16bit_branch_length (fragS *fragp, asection *sec, int update)
if (fragp
&& S_IS_DEFINED (fragp->fr_symbol)
&& !S_IS_WEAK (fragp->fr_symbol)
&& sec == S_GET_SEGMENT (fragp->fr_symbol))
{
addressT addr;

15
gas/testsuite/gas/mips/branch-weak-1.d Normal file
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@ -0,0 +1,15 @@
#objdump: -dr --prefix-addresses --show-raw-insn
#name: MIPS branch to a weak symbol
#as: -32 --defsym align=12
#source: branch-weak.s
.*: +file format .*mips.*
Disassembly of section \.text:
[0-9a-f]+ <[^>]*> 1000ffff b 00000000 <foo>
[ ]*[0-9a-f]+: R_MIPS_PC16 bar
[0-9a-f]+ <[^>]*> 00000000 nop
\.\.\.
[0-9a-f]+ <[^>]*> 03e00008 jr ra
[0-9a-f]+ <[^>]*> 00000000 nop
\.\.\.

15
gas/testsuite/gas/mips/branch-weak-2.d Normal file
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@ -0,0 +1,15 @@
#objdump: -dr --prefix-addresses --show-raw-insn
#name: microMIPS branch to a weak symbol
#as: -32 -mmicromips --defsym align=12
#source: branch-weak.s
.*: +file format .*mips.*
Disassembly of section \.text:
[0-9a-f]+ <[^>]*> 9400 fffe b 00000000 <foo>
[ ]*[0-9a-f]+: R_MICROMIPS_PC16_S1 bar
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.
[0-9a-f]+ <[^>]*> 459f jr ra
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.

16
gas/testsuite/gas/mips/branch-weak-3.d Normal file
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@ -0,0 +1,16 @@
#objdump: -dr --prefix-addresses --show-raw-insn
#name: MIPS relaxed branch to a weak symbol
#as: -32 --relax-branch --defsym align=12
#source: branch-weak.s
#stderr: branch-weak.l
.*: +file format .*mips.*
Disassembly of section \.text:
[0-9a-f]+ <[^>]*> 08000000 j 00000000 <foo>
[ ]*[0-9a-f]+: R_MIPS_26 bar
[0-9a-f]+ <[^>]*> 00000000 nop
\.\.\.
[0-9a-f]+ <[^>]*> 03e00008 jr ra
[0-9a-f]+ <[^>]*> 00000000 nop
\.\.\.

16
gas/testsuite/gas/mips/branch-weak-4.d Normal file
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@ -0,0 +1,16 @@
#objdump: -dr --prefix-addresses --show-raw-insn
#name: microMIPS relaxed branch to a weak symbol
#as: -32 -mmicromips --relax-branch --defsym align=12
#source: branch-weak.s
#stderr: branch-weak.l
.*: +file format .*mips.*
Disassembly of section \.text:
[0-9a-f]+ <[^>]*> d400 0000 j 00000000 <foo>
[ ]*[0-9a-f]+: R_MICROMIPS_26_S1 bar
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.
[0-9a-f]+ <[^>]*> 459f jr ra
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.

15
gas/testsuite/gas/mips/branch-weak-5.d Normal file
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@ -0,0 +1,15 @@
#objdump: -dr --prefix-addresses --show-raw-insn
#name: microMIPS short branch to a weak symbol
#as: -32 -mmicromips --defsym align=4
#source: branch-weak.s
.*: +file format .*mips.*
Disassembly of section \.text:
[0-9a-f]+ <[^>]*> 9400 fffe b 00000000 <foo>
[ ]*[0-9a-f]+: R_MICROMIPS_PC16_S1 bar
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.
[0-9a-f]+ <[^>]*> 459f jr ra
[0-9a-f]+ <[^>]*> 0c00 nop
\.\.\.

2
gas/testsuite/gas/mips/branch-weak.l Normal file
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@ -0,0 +1,2 @@
.*: Assembler messages:
.*:6: Warning: relaxed out-of-range branch into a jump

19
gas/testsuite/gas/mips/branch-weak.s Normal file
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@ -0,0 +1,19 @@
.text
.align 4, 0
.globl foo
.ent foo
foo:
b bar
.end foo
.align align, 0
.globl bar
.weak bar
.ent bar
bar:
jr $ra
.end bar
# Force some (non-delay-slot) zero bytes, to make 'objdump' print ...
.align 4, 0
.space 16

5
gas/testsuite/gas/mips/mips.exp
View file

@ -583,6 +583,11 @@ if { [istarget mips*-*-vxworks*] } {
run_dump_test "branch-extern-2"
run_dump_test "branch-extern-3"
run_dump_test "branch-extern-4"
run_dump_test "branch-weak-1"
run_dump_test "branch-weak-2"
run_dump_test "branch-weak-3"
run_dump_test "branch-weak-4"
run_dump_test "branch-weak-5"
run_dump_test "compact-eh-eb-1"
run_dump_test "compact-eh-eb-2"