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[AArch64] Relax long branch veneer insertion for non STT_FUNC symbol
- From: Jiong Wang <jiong dot wang at foss dot arm dot com>
- To: "binutils at sourceware dot org" <binutils at sourceware dot org>
- Date: Fri, 15 Jan 2016 16:12:58 +0000
- Subject: [AArch64] Relax long branch veneer insertion for non STT_FUNC symbol
- Authentication-results: sourceware.org; auth=none
As defined at AArch64 ELF Specification (4.6.7 Call and Jump
relocations), symbol with type of non STT_FUNC but in different input
section with relocation place should insert long branch veneer also.
Meanwhile the current long branch veneer infrastructure havn't considered
the situation where the branch destination is "sym_value + rela->addend".
This was OK because we only insert veneer for long call destination is
STT_FUNC symbol, so the addend is always zero. But as we relax the support
to other situations by this patch, we need to handle addend be non-zero
value. For example, for static function, relocation against "local symbol"
are turned into relocation against "section symbol + offset" where there is
a valid addend.
OK for master?
2016-01-15 Jiong Wang <jiong.wang@arm.com>
bfd/
(aarch64_type_of_stub): Allow insert long branch veneer for
sym_sec != input_sec.
(elfNN_aarch64_size_stub): Support STT_SECTION symbol.
(elfNN_aarch64_final_link_relocate): Take rela addend into account
when calculation destination.
ld/testsuite/
* ld-aarch64/farcall-section.d: Delete.
* ld-aarch64/farcall-section.s: Delete.
* ld-aarch64/farcall-b-section.d: New expectation file.
* ld-aarch64/farcall-bl-section.d: Likewise.
* ld-aarch64/farcall-b-section.s: New testcase.
* ld-aarch64/farcall-bl-section.s: Likewise.
* ld-aarch64/aarch64-elf.exp: Likewise.
diff --git a/bfd/elfnn-aarch64.c b/bfd/elfnn-aarch64.c
index 59c51cc..d83dc1b 100644
--- a/bfd/elfnn-aarch64.c
+++ b/bfd/elfnn-aarch64.c
@@ -2655,7 +2655,7 @@ aarch64_type_of_stub (struct bfd_link_info *info,
bfd_boolean via_plt_p;
if (st_type != STT_FUNC
- && (sym_sec != bfd_abs_section_ptr))
+ && (sym_sec == input_sec))
return stub_type;
globals = elf_aarch64_hash_table (info);
@@ -4174,7 +4174,7 @@ elfNN_aarch64_size_stubs (bfd *output_bfd,
goto error_ret_free_internal;
}
- stub_entry->target_value = sym_value;
+ stub_entry->target_value = sym_value + irela->r_addend;
stub_entry->target_section = sym_sec;
stub_entry->stub_type = stub_type;
stub_entry->h = hash;
@@ -5280,15 +5280,28 @@ elfNN_aarch64_final_link_relocate (reloc_howto_type *howto,
/* Check if a stub has to be inserted because the destination
is too far away. */
struct elf_aarch64_stub_hash_entry *stub_entry = NULL;
- if (! aarch64_valid_branch_p (value, place))
+
+ /* If the branch destination is directed to plt stub, "value" will be
+ the final destination, otherwise we should plus signed_addend, it may
+ contain non-zero value, for example call to local function symbol
+ which are turned into "sec_sym + sec_off", and sec_off is kept in
+ signed_addend. */
+ if (! aarch64_valid_branch_p (via_plt_p ? value : value + signed_addend,
+ place))
/* The target is out of reach, so redirect the branch to
the local stub for this function. */
stub_entry = elfNN_aarch64_get_stub_entry (input_section, sym_sec, h,
rel, globals);
if (stub_entry != NULL)
- value = (stub_entry->stub_offset
- + stub_entry->stub_sec->output_offset
- + stub_entry->stub_sec->output_section->vma);
+ {
+ value = (stub_entry->stub_offset
+ + stub_entry->stub_sec->output_offset
+ + stub_entry->stub_sec->output_section->vma);
+
+ /* We have redirected the destination to stub entry address,
+ so ignore any addend record in the original rela entry. */
+ signed_addend = 0;
+ }
}
value = _bfd_aarch64_elf_resolve_relocation (bfd_r_type, place, value,
signed_addend, weak_undef_p);
diff --git a/ld/testsuite/ld-aarch64/aarch64-elf.exp b/ld/testsuite/ld-aarch64/aarch64-elf.exp
index 0e5b31e..576cc65 100644
--- a/ld/testsuite/ld-aarch64/aarch64-elf.exp
+++ b/ld/testsuite/ld-aarch64/aarch64-elf.exp
@@ -170,7 +170,6 @@ run_dump_test "pcrel_pic_defined_local"
run_dump_test "limit-b"
run_dump_test "limit-bl"
-run_dump_test "farcall-section"
run_dump_test "farcall-back"
run_dump_test "farcall-b-defsym"
run_dump_test "farcall-bl-defsym"
@@ -181,6 +180,8 @@ run_dump_test "farcall-bl"
run_dump_test "farcall-b"
run_dump_test "farcall-b-none-function"
run_dump_test "farcall-bl-none-function"
+run_dump_test "farcall-b-section"
+run_dump_test "farcall-bl-section"
run_dump_test "tls-relax-all"
run_dump_test "tls-relax-gd-le"
diff --git a/ld/testsuite/ld-aarch64/farcall-b-none-function.d b/ld/testsuite/ld-aarch64/farcall-b-none-function.d
index 34a6568..ba2981f 100644
--- a/ld/testsuite/ld-aarch64/farcall-b-none-function.d
+++ b/ld/testsuite/ld-aarch64/farcall-b-none-function.d
@@ -2,4 +2,23 @@
#source: farcall-b-none-function.s
#as:
#ld: -Ttext 0x1000 --section-start .foo=0x8001000
-#error: .*\(.text\+0x0\): relocation truncated to fit: R_AARCH64_JUMP26 against symbol `bar'.*
+#objdump: -dr
+#...
+
+Disassembly of section .text:
+
+.* <_start>:
+ 1000: 14000003 b 100c <__bar_veneer>
+ 1004: d65f03c0 ret
+ 1008: 14000007 b 1024 <__bar_veneer\+0x18>
+
+.* <__bar_veneer>:
+ 100c: 90040010 adrp x16, 8001000 <bar>
+ 1010: 91000210 add x16, x16, #0x0
+ 1014: d61f0200 br x16
+ ...
+
+Disassembly of section .foo:
+
+.* <bar>:
+ 8001000: d65f03c0 ret
diff --git a/ld/testsuite/ld-aarch64/farcall-b-section.d b/ld/testsuite/ld-aarch64/farcall-b-section.d
new file mode 100644
index 0000000..4745c0f
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/farcall-b-section.d
@@ -0,0 +1,34 @@
+#name: aarch64-farcall-b-section
+#source: farcall-b-section.s
+#as:
+#ld: -Ttext 0x1000 --section-start .foo=0x8001000
+#objdump: -dr
+#...
+
+Disassembly of section .text:
+
+.* <_start>:
+ 1000: 14000008 b 1020 <___veneer>
+ 1004: 14000003 b 1010 <___veneer>
+ 1008: d65f03c0 ret
+ 100c: 1400000d b 1040 <___veneer\+0x20>
+
+.* <___veneer>:
+ 1010: 90040010 adrp x16, 8001000 <bar>
+ 1014: 91001210 add x16, x16, #0x4
+ 1018: d61f0200 br x16
+ 101c: 00000000 .inst 0x00000000 ; undefined
+
+.* <___veneer>:
+ 1020: 90040010 adrp x16, 8001000 <bar>
+ 1024: 91000210 add x16, x16, #0x0
+ 1028: d61f0200 br x16
+ ...
+
+Disassembly of section .foo:
+
+.* <bar>:
+ 8001000: d65f03c0 ret
+
+.* <bar2>:
+ 8001004: d65f03c0 ret
diff --git a/ld/testsuite/ld-aarch64/farcall-b-section.s b/ld/testsuite/ld-aarch64/farcall-b-section.s
new file mode 100644
index 0000000..1a135ef
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/farcall-b-section.s
@@ -0,0 +1,20 @@
+.global _start
+
+# We will place the section .text at 0x1000.
+
+ .text
+
+_start:
+ b bar
+ b bar2
+ ret
+
+# We will place the section .foo at 0x8001000.
+
+ .section .foo, "xa"
+ .type bar, @function
+bar:
+ ret
+ .type bar2, @function
+bar2:
+ ret
diff --git a/ld/testsuite/ld-aarch64/farcall-bl-none-function.d b/ld/testsuite/ld-aarch64/farcall-bl-none-function.d
index 6ce9ca4..b6a4dda 100644
--- a/ld/testsuite/ld-aarch64/farcall-bl-none-function.d
+++ b/ld/testsuite/ld-aarch64/farcall-bl-none-function.d
@@ -2,4 +2,23 @@
#source: farcall-bl-none-function.s
#as:
#ld: -Ttext 0x1000 --section-start .foo=0x8001000
-#error: .*\(.text\+0x0\): relocation truncated to fit: R_AARCH64_CALL26 against symbol `bar'.*
+#objdump: -dr
+#...
+
+Disassembly of section .text:
+
+.* <_start>:
+ 1000: 94000003 bl 100c <__bar_veneer>
+ 1004: d65f03c0 ret
+ 1008: 14000007 b 1024 <__bar_veneer\+0x18>
+
+.* <__bar_veneer>:
+ 100c: 90040010 adrp x16, 8001000 <bar>
+ 1010: 91000210 add x16, x16, #0x0
+ 1014: d61f0200 br x16
+ ...
+
+Disassembly of section .foo:
+
+.* <bar>:
+ 8001000: d65f03c0 ret
diff --git a/ld/testsuite/ld-aarch64/farcall-bl-section.d b/ld/testsuite/ld-aarch64/farcall-bl-section.d
new file mode 100644
index 0000000..2bd4f85
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/farcall-bl-section.d
@@ -0,0 +1,34 @@
+#name: aarch64-farcall-bl-section
+#source: farcall-bl-section.s
+#as:
+#ld: -Ttext 0x1000 --section-start .foo=0x8001000
+#objdump: -dr
+#...
+
+Disassembly of section .text:
+
+.* <_start>:
+ 1000: 94000008 bl 1020 <___veneer>
+ 1004: 94000003 bl 1010 <___veneer>
+ 1008: d65f03c0 ret
+ 100c: 1400000d b 1040 <___veneer\+0x20>
+
+.* <___veneer>:
+ 1010: 90040010 adrp x16, 8001000 <bar>
+ 1014: 91001210 add x16, x16, #0x4
+ 1018: d61f0200 br x16
+ 101c: 00000000 .inst 0x00000000 ; undefined
+
+.* <___veneer>:
+ 1020: 90040010 adrp x16, 8001000 <bar>
+ 1024: 91000210 add x16, x16, #0x0
+ 1028: d61f0200 br x16
+ ...
+
+Disassembly of section .foo:
+
+.* <bar>:
+ 8001000: d65f03c0 ret
+
+.* <bar2>:
+ 8001004: d65f03c0 ret
diff --git a/ld/testsuite/ld-aarch64/farcall-bl-section.s b/ld/testsuite/ld-aarch64/farcall-bl-section.s
new file mode 100644
index 0000000..4469d4d
--- /dev/null
+++ b/ld/testsuite/ld-aarch64/farcall-bl-section.s
@@ -0,0 +1,20 @@
+ .global _start
+
+# We will place the section .text at 0x1000.
+
+ .text
+
+_start:
+ bl bar
+ bl bar2
+ ret
+
+# We will place the section .foo at 0x8001000.
+
+ .section .foo, "xa"
+ .type bar, @function
+bar:
+ ret
+ .type bar2, @function
+bar2:
+ ret
diff --git a/ld/testsuite/ld-aarch64/farcall-section.d b/ld/testsuite/ld-aarch64/farcall-section.d
deleted file mode 100644
index 85775e1..0000000
--- a/ld/testsuite/ld-aarch64/farcall-section.d
+++ /dev/null
@@ -1,5 +0,0 @@
-#name: Aarch64 farcall to symbol of type STT_SECTION
-#source: farcall-section.s
-#as:
-#ld: -Ttext 0x1000 --section-start .foo=0x8001014
-#error: .*\(.text\+0x0\): relocation truncated to fit: R_AARCH64_CALL26 against `.foo'
diff --git a/ld/testsuite/ld-aarch64/farcall-section.s b/ld/testsuite/ld-aarch64/farcall-section.s
deleted file mode 100644
index 86a070c..0000000
--- a/ld/testsuite/ld-aarch64/farcall-section.s
+++ /dev/null
@@ -1,19 +0,0 @@
-# Test to ensure that an Aarch64 call exceeding 128MB generates an error
-# if the destination is of type STT_SECTION (eg non-global symbol)
-
- .global _start
-
-# We will place the section .text at 0x1000.
-
- .text
-
-_start:
- bl bar
-
-# We will place the section .foo at 0x8001020.
-
- .section .foo, "xa"
-
-bar:
- ret
-