[RFC PATCH, binutils, ARM 2/9] Factor our stub creation in ARM backend
Thomas Preud'homme
thomas.preudhomme@foss.arm.com
Wed Dec 23 07:55:00 GMT 2015
Hi,
[Posting patch series as RFC]
This patch is part of a patch series to add support for ARMv8-M security extension[1] to GNU ld. This specific patch factors out the code to create a stub in ARM backend to avoid code duplication in subsequent patches adding new code for creating Secure Gateway veneers.
[1] Software requirements for ARMv8-M security extension are described in document ARM-ECM-0359818 [2]
[2] Available on http://infocenter.arm.com in Developer guides and articles > Software development > ARM®v8-M Security Extensions: Requirements on Development Tools
ChangeLog entries is as follows:
*** bfd/ChangeLog ***
2015-12-16 Thomas Preud'homme <thomas.preudhomme@arm.com>
* elf32-arm.c (elf32_arm_create_stub): New function.
(elf32_arm_size_stubs): Use elf32_arm_create_stub for stub creation.
diff --git a/bfd/elf32-arm.c b/bfd/elf32-arm.c
index 639fe0f125688ccf218b449467c746686841386f..e6afb99512524ac26c0e3842e8dbe293c58bacad 100644
--- a/bfd/elf32-arm.c
+++ b/bfd/elf32-arm.c
@@ -5031,6 +5031,103 @@ cortex_a8_erratum_scan (bfd *input_bfd,
return FALSE;
}
+/* Create or update a stub entry depending on whether the stub can already be
+ found in HTAB. The stub is identified by:
+ - its type STUB_TYPE
+ - its source branch (note that several can share the same stub) whose
+ section and relocation (if any) are given by SECTION and IRELA
+ respectively
+ - its target symbol whose input section, hash, name, value and branch type
+ are given in SYM_SEC, HASH, SYM_NAME, SYM_VALUE and BRANCH_TYPE
+ respectively
+
+ If found, the value of the stub's target symbol is updated from SYM_VALUE
+ and *NEW_STUB is set to FALSE. Otherwise, *NEW_STUB is set to
+ TRUE and the stub entry is initialized.
+
+ Returns whether the stub could be successfully created or updated, or FALSE
+ if an error occured. */
+
+static bfd_boolean
+elf32_arm_create_stub (struct elf32_arm_link_hash_table *htab,
+ enum elf32_arm_stub_type stub_type, asection *section,
+ Elf_Internal_Rela *irela, asection *sym_sec,
+ struct elf32_arm_link_hash_entry *hash, char *sym_name,
+ bfd_vma sym_value, enum arm_st_branch_type branch_type,
+ bfd_boolean *new_stub)
+{
+ const asection *id_sec;
+ char *stub_name;
+ struct elf32_arm_stub_hash_entry *stub_entry;
+ unsigned int r_type;
+
+ BFD_ASSERT (stub_type != arm_stub_none);
+ *new_stub = FALSE;
+
+ BFD_ASSERT (irela);
+ BFD_ASSERT (section);
+
+ /* Support for grouping stub sections. */
+ id_sec = htab->stub_group[section->id].link_sec;
+
+ /* Get the name of this stub. */
+ stub_name = elf32_arm_stub_name (id_sec, sym_sec, hash, irela, stub_type);
+ if (!stub_name)
+ return FALSE;
+
+ stub_entry = arm_stub_hash_lookup (&htab->stub_hash_table, stub_name, FALSE,
+ FALSE);
+ /* The proper stub has already been created, just update its value. */
+ if (stub_entry != NULL)
+ {
+ free (stub_name);
+ stub_entry->target_value = sym_value;
+ return TRUE;
+ }
+
+ stub_entry = elf32_arm_add_stub (stub_name, section, htab);
+ if (stub_entry == NULL)
+ {
+ free (stub_name);
+ return FALSE;
+ }
+
+ stub_entry->target_value = sym_value;
+ stub_entry->target_section = sym_sec;
+ stub_entry->stub_type = stub_type;
+ stub_entry->h = hash;
+ stub_entry->branch_type = branch_type;
+
+ if (sym_name == NULL)
+ sym_name = "unnamed";
+ stub_entry->output_name = (char *)
+ bfd_alloc (htab->stub_bfd, sizeof (THUMB2ARM_GLUE_ENTRY_NAME)
+ + strlen (sym_name));
+ if (stub_entry->output_name == NULL)
+ {
+ free (stub_name);
+ return FALSE;
+ }
+
+ /* For historical reasons, use the existing names for ARM-to-Thumb and
+ Thumb-to-ARM stubs. */
+ r_type = ELF32_R_TYPE (irela->r_info);
+ if ((r_type == (unsigned int) R_ARM_THM_CALL
+ || r_type == (unsigned int) R_ARM_THM_JUMP24
+ || r_type == (unsigned int) R_ARM_THM_JUMP19)
+ && branch_type == ST_BRANCH_TO_ARM)
+ sprintf (stub_entry->output_name, THUMB2ARM_GLUE_ENTRY_NAME, sym_name);
+ else if ((r_type == (unsigned int) R_ARM_CALL
+ || r_type == (unsigned int) R_ARM_JUMP24)
+ && branch_type == ST_BRANCH_TO_THUMB)
+ sprintf (stub_entry->output_name, ARM2THUMB_GLUE_ENTRY_NAME, sym_name);
+ else
+ sprintf (stub_entry->output_name, STUB_ENTRY_NAME, sym_name);
+
+ *new_stub = TRUE;
+ return TRUE;
+}
+
/* Determine and set the size of the stub section for a final link.
The basic idea here is to examine all the relocations looking for
@@ -5174,14 +5271,11 @@ elf32_arm_size_stubs (bfd *output_bfd,
{
unsigned int r_type, r_indx;
enum elf32_arm_stub_type stub_type;
- struct elf32_arm_stub_hash_entry *stub_entry;
asection *sym_sec;
bfd_vma sym_value;
bfd_vma destination;
struct elf32_arm_link_hash_entry *hash;
const char *sym_name;
- char *stub_name;
- const asection *id_sec;
unsigned char st_type;
enum arm_st_branch_type branch_type;
bfd_boolean created_stub = FALSE;
@@ -5364,6 +5458,8 @@ elf32_arm_size_stubs (bfd *output_bfd,
do
{
+ bfd_boolean new_stub;
+
/* Determine what (if any) linker stub is needed. */
stub_type = arm_type_of_stub (info, section, irela,
st_type, &branch_type,
@@ -5372,74 +5468,21 @@ elf32_arm_size_stubs (bfd *output_bfd,
if (stub_type == arm_stub_none)
break;
- /* Support for grouping stub sections. */
- id_sec = htab->stub_group[section->id].link_sec;
-
- /* Get the name of this stub. */
- stub_name = elf32_arm_stub_name (id_sec, sym_sec, hash,
- irela, stub_type);
- if (!stub_name)
- goto error_ret_free_internal;
-
/* We've either created a stub for this reloc already,
or we are about to. */
- created_stub = TRUE;
-
- stub_entry = arm_stub_hash_lookup
- (&htab->stub_hash_table, stub_name,
- FALSE, FALSE);
- if (stub_entry != NULL)
- {
- /* The proper stub has already been created. */
- free (stub_name);
- stub_entry->target_value = sym_value;
- break;
- }
-
- stub_entry = elf32_arm_add_stub (stub_name, section,
- htab);
- if (stub_entry == NULL)
- {
- free (stub_name);
- goto error_ret_free_internal;
- }
+ created_stub =
+ elf32_arm_create_stub (htab, stub_type, section, irela,
+ sym_sec, hash,
+ (char *) sym_name, sym_value,
+ branch_type, &new_stub);
- stub_entry->target_value = sym_value;
- stub_entry->target_section = sym_sec;
- stub_entry->stub_type = stub_type;
- stub_entry->h = hash;
- stub_entry->branch_type = branch_type;
-
- if (sym_name == NULL)
- sym_name = "unnamed";
- stub_entry->output_name = (char *)
- bfd_alloc (htab->stub_bfd,
- sizeof (THUMB2ARM_GLUE_ENTRY_NAME)
- + strlen (sym_name));
- if (stub_entry->output_name == NULL)
+ if (!created_stub || !new_stub)
{
- free (stub_name);
- goto error_ret_free_internal;
+ if (!created_stub)
+ goto error_ret_free_internal;
}
-
- /* For historical reasons, use the existing names for
- ARM-to-Thumb and Thumb-to-ARM stubs. */
- if ((r_type == (unsigned int) R_ARM_THM_CALL
- || r_type == (unsigned int) R_ARM_THM_JUMP24
- || r_type == (unsigned int) R_ARM_THM_JUMP19)
- && branch_type == ST_BRANCH_TO_ARM)
- sprintf (stub_entry->output_name,
- THUMB2ARM_GLUE_ENTRY_NAME, sym_name);
- else if ((r_type == (unsigned int) R_ARM_CALL
- || r_type == (unsigned int) R_ARM_JUMP24)
- && branch_type == ST_BRANCH_TO_THUMB)
- sprintf (stub_entry->output_name,
- ARM2THUMB_GLUE_ENTRY_NAME, sym_name);
else
- sprintf (stub_entry->output_name, STUB_ENTRY_NAME,
- sym_name);
-
- stub_changed = TRUE;
+ stub_changed = TRUE;
}
while (0);
The patch doesn't show any regression when running the binutils-gdb testsuite for the arm-none-eabi target.
Any comments?
Best regards,
Thomas
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