[RFC 1/5] xtensa: don't expect XCHAL_* macros to be constant

[Max Filippov <jcmvbkbc at gmail dot com>]

Get rid of the assumption that XCHAL_* macros are preprocessor
constants: don't use them in preprocessor conditionals or in static
variable initializers.

2017-05-22  Max Filippov  <jcmvbkbc@gmail.com>
bfd/
	* elf32-xtensa.c (elf_xtensa_be_plt_entry,
	elf_xtensa_le_plt_entry): Add dimension for the ABI to arrays,
	keep both windowed and call0 ABI PLT definitions.
	(elf_xtensa_create_plt_entry): Use selected ABI to choose upper
	elf_xtensa_*_plt_entry endex.
	(ELF_MAXPAGESIZE): Fix at minimal supported MMU page size.

gas/
	* config/tc-xtensa.c (density_supported, xtensa_fetch_width,
	absolute_literals_supported): Leave definitions uninitialized.
	(directive_state): Leave entries for directive_density and
	directive_absolute_literals initialized to false.
	(xg_init_global_config, xtensa_init): New functions.
	* config/tc-xtensa.h (TARGET_BYTES_BIG_ENDIAN): Define as 0.
	(HOST_SPECIAL_INIT): New definition.
	(xtensa_init): New declaration.
---
 bfd/elf32-xtensa.c     | 60 +++++++++++++++++++++++++++++---------------------
 gas/config/tc-xtensa.c | 32 ++++++++++++++++++---------
 gas/config/tc-xtensa.h |  9 +++++++-
 3 files changed, 64 insertions(+), 37 deletions(-)

diff --git a/bfd/elf32-xtensa.c b/bfd/elf32-xtensa.c
index 80f50e3..078918f 100644
--- a/bfd/elf32-xtensa.c
+++ b/bfd/elf32-xtensa.c
@@ -519,28 +519,42 @@ elf_xtensa_info_to_howto_rela (bfd *abfd ATTRIBUTE_UNUSED,
    invoked.  Note: the 32-byte frame size used here cannot be changed
    without a corresponding change in the runtime linker.  */
 
-static const bfd_byte elf_xtensa_be_plt_entry[PLT_ENTRY_SIZE] =
+static const bfd_byte elf_xtensa_be_plt_entry[][PLT_ENTRY_SIZE] =
 {
-#if XSHAL_ABI == XTHAL_ABI_WINDOWED
-  0x6c, 0x10, 0x04,	/* entry sp, 32 */
-#endif
-  0x18, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
-  0x1a, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
-  0x1b, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
-  0x0a, 0x80, 0x00,	/* jx    a8 */
-  0			/* unused */
+    {
+      0x6c, 0x10, 0x04,	/* entry sp, 32 */
+      0x18, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
+      0x1a, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
+      0x1b, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
+      0x0a, 0x80, 0x00,	/* jx    a8 */
+      0			/* unused */
+    },
+    {
+      0x18, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
+      0x1a, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
+      0x1b, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
+      0x0a, 0x80, 0x00,	/* jx    a8 */
+      0			/* unused */
+    }
 };
 
-static const bfd_byte elf_xtensa_le_plt_entry[PLT_ENTRY_SIZE] =
+static const bfd_byte elf_xtensa_le_plt_entry[][PLT_ENTRY_SIZE] =
 {
-#if XSHAL_ABI == XTHAL_ABI_WINDOWED
-  0x36, 0x41, 0x00,	/* entry sp, 32 */
-#endif
-  0x81, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
-  0xa1, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
-  0xb1, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
-  0xa0, 0x08, 0x00,	/* jx    a8 */
-  0			/* unused */
+    {
+      0x36, 0x41, 0x00,	/* entry sp, 32 */
+      0x81, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
+      0xa1, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
+      0xb1, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
+      0xa0, 0x08, 0x00,	/* jx    a8 */
+      0			/* unused */
+    },
+    {
+      0x81, 0x00, 0x00,	/* l32r  a8, [got entry for rtld's resolver] */
+      0xa1, 0x00, 0x00,	/* l32r  a10, [got entry for rtld's link map] */
+      0xb1, 0x00, 0x00,	/* l32r  a11, [literal for reloc index] */
+      0xa0, 0x08, 0x00,	/* jx    a8 */
+      0			/* unused */
+    }
 };
 
 /* The size of the thread control block.  */
@@ -2336,8 +2350,8 @@ 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
-	   : elf_xtensa_le_plt_entry),
+	   ? elf_xtensa_be_plt_entry[XSHAL_ABI != XTHAL_ABI_WINDOWED]
+	   : elf_xtensa_le_plt_entry[XSHAL_ABI != XTHAL_ABI_WINDOWED]),
 	  PLT_ENTRY_SIZE);
   abi_offset = XSHAL_ABI == XTHAL_ABI_WINDOWED ? 3 : 0;
   bfd_put_16 (output_bfd, l32r_offset (got_base + 0,
@@ -11317,11 +11331,7 @@ static const struct bfd_elf_special_section elf_xtensa_special_sections[] =
 #define ELF_MACHINE_CODE		EM_XTENSA
 #define ELF_MACHINE_ALT1		EM_XTENSA_OLD
 
-#if XCHAL_HAVE_MMU
-#define ELF_MAXPAGESIZE			(1 << XCHAL_MMU_MIN_PTE_PAGE_SIZE)
-#else /* !XCHAL_HAVE_MMU */
-#define ELF_MAXPAGESIZE			1
-#endif /* !XCHAL_HAVE_MMU */
+#define ELF_MAXPAGESIZE			0x1000
 #endif /* ELF_ARCH */
 
 #define elf_backend_can_gc_sections	1
diff --git a/gas/config/tc-xtensa.c b/gas/config/tc-xtensa.c
index bac7946..ed7ba0a 100644
--- a/gas/config/tc-xtensa.c
+++ b/gas/config/tc-xtensa.c
@@ -72,13 +72,13 @@ const char FLT_CHARS[] = "rRsSfFdDxXpP";
 /* Flags to indicate whether the hardware supports the density and
    absolute literals options.  */
 
-bfd_boolean density_supported = XCHAL_HAVE_DENSITY;
-bfd_boolean absolute_literals_supported = XSHAL_USE_ABSOLUTE_LITERALS;
+bfd_boolean density_supported;
+bfd_boolean absolute_literals_supported;
 
 static vliw_insn cur_vinsn;
 
 unsigned xtensa_num_pipe_stages;
-unsigned xtensa_fetch_width = XCHAL_INST_FETCH_WIDTH;
+unsigned xtensa_fetch_width;
 
 static enum debug_info_type xt_saved_debug_type = DEBUG_NONE;
 
@@ -419,21 +419,13 @@ bfd_boolean directive_state[] =
 {
   FALSE,			/* none */
   FALSE,			/* literal */
-#if !XCHAL_HAVE_DENSITY
   FALSE,			/* density */
-#else
-  TRUE,				/* density */
-#endif
   TRUE,				/* transform */
   FALSE,			/* freeregs */
   FALSE,			/* longcalls */
   FALSE,			/* literal_prefix */
   FALSE,			/* schedule */
-#if XSHAL_USE_ABSOLUTE_LITERALS
-  TRUE				/* absolute_literals */
-#else
   FALSE				/* absolute_literals */
-#endif
 };
 
 /* A circular list of all potential and actual literal pool locations
@@ -5216,6 +5208,24 @@ md_number_to_chars (char *buf, valueT val, int n)
     number_to_chars_littleendian (buf, val, n);
 }
 
+static void
+xg_init_global_config (void)
+{
+  target_big_endian = XCHAL_HAVE_BE;
+
+  density_supported = XCHAL_HAVE_DENSITY;
+  absolute_literals_supported = XSHAL_USE_ABSOLUTE_LITERALS;
+  xtensa_fetch_width = XCHAL_INST_FETCH_WIDTH;
+
+  directive_state[directive_density] = XCHAL_HAVE_DENSITY;
+  directive_state[directive_absolute_literals] = XSHAL_USE_ABSOLUTE_LITERALS;
+}
+
+void
+xtensa_init (int argc ATTRIBUTE_UNUSED, char **argv ATTRIBUTE_UNUSED)
+{
+  xg_init_global_config ();
+}
 
 /* This function is called once, at assembler startup time.  It should
    set up all the tables, etc. that the MD part of the assembler will
diff --git a/gas/config/tc-xtensa.h b/gas/config/tc-xtensa.h
index 50e4640..69a5c8a 100644
--- a/gas/config/tc-xtensa.h
+++ b/gas/config/tc-xtensa.h
@@ -30,7 +30,7 @@ struct fix;
 #include "xtensa-isa.h"
 #include "xtensa-config.h"
 
-#define TARGET_BYTES_BIG_ENDIAN XCHAL_HAVE_BE
+#define TARGET_BYTES_BIG_ENDIAN 0
 
 
 /* Maximum number of opcode slots in a VLIW instruction.  */
@@ -335,6 +335,13 @@ extern bfd_boolean xtensa_check_inside_bundle (void);
 extern void xtensa_handle_align (fragS *);
 extern char *xtensa_section_rename (const char *);
 
+/* We need to set the target endianness in xtensa_init and not in md_begin.
+   This is because xtensa_target_format is called before md_begin, and we
+   want to have all non-statically initialized fields initialized.  */
+
+#define HOST_SPECIAL_INIT xtensa_init
+extern void xtensa_init (int, char **);
+
 #define TARGET_FORMAT			xtensa_target_format ()
 #define TARGET_ARCH			bfd_arch_xtensa
 #define TC_SEGMENT_INFO_TYPE		xtensa_segment_info
-- 
2.1.4