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authorClaudiu Zissulescu <claziss@gmail.com>2019-07-24 16:33:29 +0300
committerClaudiu Zissulescu <claziss@gmail.com>2019-07-24 16:33:29 +0300
commitef551643dc282159185cb9916c7cb0308ae03cdd (patch)
tree90007b800835a19087ca4580e7a061ca5dad491e
parentc54e42531adb7bf8d58bd4c3c8e0c710305959e1 (diff)
downloadbinutils-ef551643dc282159185cb9916c7cb0308ae03cdd.tar.gz
binutils-ef551643dc282159185cb9916c7cb0308ae03cdd.tar.xz
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[ARC] Add linker relaxation.
Add linker relaxation. The first relaxation added is converting GOTPC32 to PCREL relocations. This relaxation doesn't change the size of the binary. bfd/ xxxx-xx-xx Claudiu Zissulescu <claziss@synopsys.com> * elf32-arc.c (bfd_get_32_me): New function. (bfd_put_32_me): Likewise. (arc_elf_relax_section): Likewise. (bfd_elf32_bfd_relax_section): Define. ld/testsuite/ xxxx-xx-xx Claudiu Zissulescu <claziss@synopsys.com> * ld-arc/relax-local-pic.d: New test. * ld-arc/relax-local-pic.s: New file.
-rw-r--r--bfd/ChangeLog7
-rw-r--r--bfd/elf32-arc.c176
-rw-r--r--ld/ChangeLog5
-rw-r--r--ld/testsuite/ld-arc/relax-local-pic.d14
-rw-r--r--ld/testsuite/ld-arc/relax-local-pic.s16
5 files changed, 218 insertions, 0 deletions
diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 6d7e42510a..50027c63f3 100644
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,10 @@
+2019-07-24 Claudiu Zissulescu <claziss@synopsys.com>
+
+ * elf32-arc.c (bfd_get_32_me): New function.
+ (bfd_put_32_me): Likewise.
+ (arc_elf_relax_section): Likewise.
+ (bfd_elf32_bfd_relax_section): Define.
+
2019-07-24 Alan Modra <amodra@gmail.com>
* elf-bfd.h (struct elf_backend_data): Return bfd_boolean from
diff --git a/bfd/elf32-arc.c b/bfd/elf32-arc.c
index c7ffc6a6f9..b069e3fda5 100644
--- a/bfd/elf32-arc.c
+++ b/bfd/elf32-arc.c
@@ -96,6 +96,31 @@ reloc_type_to_name (unsigned int type)
#define USE_REL 1
+static bfd_vma
+bfd_get_32_me (bfd * abfd,const unsigned char * data)
+{
+ bfd_vma value = 0;
+
+ if (bfd_big_endian(abfd)) {
+ value = bfd_get_32 (abfd, data);
+ }
+ else {
+ value = ((bfd_get_8 (abfd, data) & 255) << 16);
+ value |= ((bfd_get_8 (abfd, data + 1) & 255) << 24);
+ value |= (bfd_get_8 (abfd, data + 2) & 255);
+ value |= ((bfd_get_8 (abfd, data + 3) & 255) << 8);
+ }
+
+ return value;
+}
+
+static void
+bfd_put_32_me (bfd *abfd, bfd_vma value,unsigned char *data)
+{
+ bfd_put_16 (abfd, (value & 0xffff0000) >> 16, data);
+ bfd_put_16 (abfd, value & 0xffff, data + 2);
+}
+
static ATTRIBUTE_UNUSED bfd_boolean
is_reloc_PC_relative (reloc_howto_type *howto)
{
@@ -2968,6 +2993,156 @@ elf32_arc_section_from_shdr (bfd *abfd,
return TRUE;
}
+/* Relaxation hook.
+
+ These are the current relaxing opportunities available:
+
+ * R_ARC_GOTPC32 => R_ARC_PCREL.
+
+*/
+
+static bfd_boolean
+arc_elf_relax_section (bfd *abfd, asection *sec,
+ struct bfd_link_info *link_info, bfd_boolean *again)
+{
+ Elf_Internal_Shdr *symtab_hdr;
+ Elf_Internal_Rela *internal_relocs;
+ Elf_Internal_Rela *irel, *irelend;
+ bfd_byte *contents = NULL;
+ Elf_Internal_Sym *isymbuf = NULL;
+
+ /* Assume nothing changes. */
+ *again = FALSE;
+
+ /* We don't have to do anything for a relocatable link, if this
+ section does not have relocs, or if this is not a code
+ section. */
+ if (bfd_link_relocatable (link_info)
+ || (sec->flags & SEC_RELOC) == 0
+ || sec->reloc_count == 0
+ || (sec->flags & SEC_CODE) == 0)
+ return TRUE;
+
+ symtab_hdr = &elf_tdata (abfd)->symtab_hdr;
+
+ /* Get a copy of the native relocations. */
+ internal_relocs = _bfd_elf_link_read_relocs (abfd, sec, NULL, NULL,
+ link_info->keep_memory);
+ if (internal_relocs == NULL)
+ goto error_return;
+
+ /* Walk through them looking for relaxing opportunities. */
+ irelend = internal_relocs + sec->reloc_count;
+ for (irel = internal_relocs; irel < irelend; irel++)
+ {
+ /* If this isn't something that can be relaxed, then ignore
+ this reloc. */
+ if (ELF32_R_TYPE (irel->r_info) != (int) R_ARC_GOTPC32)
+ continue;
+
+ /* Get the section contents if we haven't done so already. */
+ if (contents == NULL)
+ {
+ /* Get cached copy if it exists. */
+ if (elf_section_data (sec)->this_hdr.contents != NULL)
+ contents = elf_section_data (sec)->this_hdr.contents;
+ /* Go get them off disk. */
+ else if (!bfd_malloc_and_get_section (abfd, sec, &contents))
+ goto error_return;
+ }
+
+ /* Read this BFD's local symbols if we haven't done so already. */
+ if (isymbuf == NULL && symtab_hdr->sh_info != 0)
+ {
+ isymbuf = (Elf_Internal_Sym *) symtab_hdr->contents;
+ if (isymbuf == NULL)
+ isymbuf = bfd_elf_get_elf_syms (abfd, symtab_hdr,
+ symtab_hdr->sh_info, 0,
+ NULL, NULL, NULL);
+ if (isymbuf == NULL)
+ goto error_return;
+ }
+
+ struct elf_link_hash_entry *htop = NULL;
+
+ if (ELF32_R_SYM (irel->r_info) >= symtab_hdr->sh_info)
+ {
+ /* An external symbol. */
+ unsigned int indx = ELF32_R_SYM (irel->r_info) - symtab_hdr->sh_info;
+ htop = elf_sym_hashes (abfd)[indx];
+ }
+
+ if (ELF32_R_TYPE (irel->r_info) == (int) R_ARC_GOTPC32
+ && SYMBOL_REFERENCES_LOCAL (link_info, htop))
+ {
+ unsigned int code;
+
+ /* Get the opcode. */
+ code = bfd_get_32_me (abfd, contents + irel->r_offset - 4);
+
+ /* Note that we've changed the relocs, section contents, etc. */
+ elf_section_data (sec)->relocs = internal_relocs;
+ elf_section_data (sec)->this_hdr.contents = contents;
+ symtab_hdr->contents = (unsigned char *) isymbuf;
+
+ /* Fix the relocation's type. */
+ irel->r_info = ELF32_R_INFO (ELF32_R_SYM (irel->r_info), R_ARC_PC32);
+
+ /* ld rA,[pcl,symbol@tgot] -> add rA,pcl,symbol@pcl. */
+ /* 0010 0bbb aa11 0ZZX DBBB 1111 10AA AAAA.
+ 111 00 000 0111 xx xxxx*/
+ code &= ~0x27307F80;
+ BFD_ASSERT (code <= 62UL);
+ code |= 0x27007F80;
+
+ /* Write back the new instruction. */
+ bfd_put_32_me (abfd, code, contents + irel->r_offset - 4);
+
+ /* The size isn't changed, don't redo. */
+ *again = FALSE;
+ }
+ }
+
+ if (isymbuf != NULL
+ && symtab_hdr->contents != (unsigned char *) isymbuf)
+ {
+ if (!link_info->keep_memory)
+ free (isymbuf);
+ else
+ /* Cache the symbols for elf_link_input_bfd. */
+ symtab_hdr->contents = (unsigned char *) isymbuf;
+ }
+
+ if (contents != NULL
+ && elf_section_data (sec)->this_hdr.contents != contents)
+ {
+ if (!link_info->keep_memory)
+ free (contents);
+ else
+ /* Cache the section contents for elf_link_input_bfd. */
+ elf_section_data (sec)->this_hdr.contents = contents;
+ }
+
+ if (internal_relocs != NULL
+ && elf_section_data (sec)->relocs != internal_relocs)
+ free (internal_relocs);
+
+ return TRUE;
+
+ error_return:
+ if (isymbuf != NULL
+ && symtab_hdr->contents != (unsigned char *) isymbuf)
+ free (isymbuf);
+ if (contents != NULL
+ && elf_section_data (sec)->this_hdr.contents != contents)
+ free (contents);
+ if (internal_relocs != NULL
+ && elf_section_data (sec)->relocs != internal_relocs)
+ free (internal_relocs);
+
+ return FALSE;
+}
+
#define TARGET_LITTLE_SYM arc_elf32_le_vec
#define TARGET_LITTLE_NAME "elf32-littlearc"
#define TARGET_BIG_SYM arc_elf32_be_vec
@@ -2985,6 +3160,7 @@ elf32_arc_section_from_shdr (bfd *abfd,
#define bfd_elf32_bfd_set_private_flags arc_elf_set_private_flags
#define bfd_elf32_bfd_print_private_bfd_data arc_elf_print_private_bfd_data
#define bfd_elf32_bfd_copy_private_bfd_data arc_elf_copy_private_bfd_data
+#define bfd_elf32_bfd_relax_section arc_elf_relax_section
#define elf_info_to_howto_rel arc_info_to_howto_rel
#define elf_backend_object_p arc_elf_object_p
diff --git a/ld/ChangeLog b/ld/ChangeLog
index de47676ab6..b42f4a7ecb 100644
--- a/ld/ChangeLog
+++ b/ld/ChangeLog
@@ -1,3 +1,8 @@
+2019-07-24 Claudiu Zissulescu <claziss@synopsys.com>
+
+ * ld-arc/relax-local-pic.d: New test.
+ * ld-arc/relax-local-pic.s: New file.
+
2019-07-22 Martin Liska <mliska@suse.cz>
* testsuite/ld-plugin/lto-3r.d: Remove.
diff --git a/ld/testsuite/ld-arc/relax-local-pic.d b/ld/testsuite/ld-arc/relax-local-pic.d
new file mode 100644
index 0000000000..5ed268809a
--- /dev/null
+++ b/ld/testsuite/ld-arc/relax-local-pic.d
@@ -0,0 +1,14 @@
+#source: relax-local-pic.s
+#as:
+#ld: -q -A elf32-arclittle -relax
+#objdump: -dr
+
+[^:]+: file format elf32-.*arc
+
+
+Disassembly of section \.text:
+
+00000100 <__start>:
+ 100: 2700 7f84 0000 [0-9a-f]+ add r4,pcl,0x[0-9a-f]+.*
+ 104: R_ARC_PC32 a_in_other_thread
+ 108: 1c00 [0-9a-f\s]+ st\s+.*
diff --git a/ld/testsuite/ld-arc/relax-local-pic.s b/ld/testsuite/ld-arc/relax-local-pic.s
new file mode 100644
index 0000000000..66c48b4ad7
--- /dev/null
+++ b/ld/testsuite/ld-arc/relax-local-pic.s
@@ -0,0 +1,16 @@
+ .section .text
+ .align 4
+ .global __start
+ .type __start, @function
+__start:
+ ld r4,[pcl,@a_in_other_thread@gotpc]
+ st 1,[r4]
+ .size __start, .-__start
+
+ .global a_in_other_thread
+ .section .data
+ .align 4
+ .type a_in_other_thread, @object
+ .size a_in_other_thread, 4
+a_in_other_thread:
+ .word -559038737