xtensa: allow runtime ABI selection

2020-06-15  Max Filippov  <jcmvbkbc@gmail.com>
bfd/
	* elf32-xtensa.c (XSHAL_ABI, XTHAL_ABI_UNDEFINED)
	(XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New macros.
	(elf32xtensa_abi): New global variable.
	(xtensa_abi_choice): New function.
	(elf_xtensa_create_plt_entry): Use xtensa_abi_choice instead of
	XSHAL_ABI to select PLT code.

gas/
	* config/tc-xtensa.c (XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New
	macros.
	(elf32xtensa_abi): New declaration.
	(option_abi_windowed, option_abi_call0): New enum constants.
	(md_longopts): Add entries for --abi-windowed and --abi-call0.
	(md_parse_option): Add handlers for --abi-windowed and
	--abi-call0.
	(xtensa_add_config_info): Use xtensa_abi_choice instead of
	XSHAL_ABI to format ABI tag.
	* doc/as.texi (Target Xtensa options): Add --abi-windowed and
	--abi-call0 to the list of options.
	* doc/c-xtensa.texi: Add description for options --abi-windowed
	and --abi-call0.
	* testsuite/gas/xtensa/abi-call0.d: New test definition.
	* testsuite/gas/xtensa/abi-windowed.d: New test definition.
	* testsuite/gas/xtensa/abi.s: New test source.

include/
	* elf/xtensa.h (xtensa_abi_choice): New declaration.

ld/
	* emultempl/xtensaelf.em (XSHAL_ABI): Remove macro definition.
	(XTHAL_ABI_UNDEFINED, XTHAL_ABI_WINDOWED, XTHAL_ABI_CALL0): New
	macros.
	(elf32xtensa_abi): New declaration.
	(xt_config_info_unpack_and_check): Set elf32xtensa_abi if it is
	undefined.  Use xtensa_abi_choice instead of XSHAL_ABI to test
	ABI tag consistency.
	(xtensa_add_config_info): Use xtensa_abi_choice instead of
	XSHAL_ABI to format ABI tag.
	(PARSE_AND_LIST_PROLOGUE): Define OPTION_ABI_WINDOWED,
	OPTION_ABI_CALL0 and declare elf32xtensa_abi.
	(PARSE_AND_LIST_LONGOPTS): Add entries for --abi-windowed and
	--abi-call0.
	(PARSE_AND_LIST_OPTIONS): Add help text for --abi-windowed and
	--abi-call0.
	(PARSE_AND_LIST_ARGS_CASES): Add handlers for --abi-windowed and
	--abi-call0.
	* ld.texi: Add description for options --abi-windowed and
	--abi-call0.

1 files changed, 31 insertions, 3 deletions

diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
index 9dc815e..b223424 100644
--- a/bfd/elf32-xtensa.c
+++ b/bfd/elf32-xtensa.c
@@ -37,6 +37,22 @@
 
 #define XTENSA_NO_NOP_REMOVAL 0
 
+#ifndef XSHAL_ABI
+#define XSHAL_ABI 0
+#endif
+
+#ifndef XTHAL_ABI_UNDEFINED
+#define XTHAL_ABI_UNDEFINED -1
+#endif
+
+#ifndef XTHAL_ABI_WINDOWED
+#define XTHAL_ABI_WINDOWED 0
+#endif
+
+#ifndef XTHAL_ABI_CALL0
+#define XTHAL_ABI_CALL0 1
+#endif
+
 /* Local helper functions.  */
 
 static bfd_boolean add_extra_plt_sections (struct bfd_link_info *, int);
@@ -164,6 +180,10 @@ int elf32xtensa_no_literal_movement = 1;
 
 bfd_boolean elf32xtensa_separate_props = FALSE;
 
+/* Xtensa ABI.  It affects PLT entry code.  */
+
+int elf32xtensa_abi = XTHAL_ABI_UNDEFINED;
+
 /* Rename one of the generic section flags to better document how it
    is used here.  */
 /* Whether relocations have been processed.  */
@@ -2247,6 +2267,13 @@ bfd_elf_xtensa_reloc (bfd *abfd,
   return flag;
 }
 
+int xtensa_abi_choice (void)
+{
+  if (elf32xtensa_abi == XTHAL_ABI_UNDEFINED)
+    return XSHAL_ABI;
+  else
+    return elf32xtensa_abi;
+}
 
 /* Set up an entry in the procedure linkage table.  */
 
@@ -2259,6 +2286,7 @@ elf_xtensa_create_plt_entry (struct bfd_link_info *info,
   bfd_vma plt_base, got_base;
   bfd_vma code_offset, lit_offset, abi_offset;
   int chunk;
+  int abi = xtensa_abi_choice ();
 
   chunk = reloc_index / PLT_ENTRIES_PER_CHUNK;
   splt = elf_xtensa_get_plt_section (info, chunk);
@@ -2279,10 +2307,10 @@ elf_xtensa_create_plt_entry (struct bfd_link_info *info,
   /* Fill in the entry in the procedure linkage table.  */
   memcpy (splt->contents + code_offset,
 	  (bfd_big_endian (output_bfd)
-	   ? elf_xtensa_be_plt_entry[XSHAL_ABI != XTHAL_ABI_WINDOWED]
-	   : elf_xtensa_le_plt_entry[XSHAL_ABI != XTHAL_ABI_WINDOWED]),
+	   ? elf_xtensa_be_plt_entry[abi != XTHAL_ABI_WINDOWED]
+	   : elf_xtensa_le_plt_entry[abi != XTHAL_ABI_WINDOWED]),
 	  PLT_ENTRY_SIZE);
-  abi_offset = XSHAL_ABI == XTHAL_ABI_WINDOWED ? 3 : 0;
+  abi_offset = abi == XTHAL_ABI_WINDOWED ? 3 : 0;
   bfd_put_16 (output_bfd, l32r_offset (got_base + 0,
 				       plt_base + code_offset + abi_offset),
 	      splt->contents + code_offset + abi_offset + 1);