[02/30,arm] Rewrite -march and -mcpu options for passing to the assembler

Message ID d75dea2aae7ca0ac7d3dc84ce2fce5ce5a04407b.1497004220.git.Richard.Earnshaw@arm.com
State New
Headers show
Series
  • Reworking the -mcpu, -march and -mfpu options
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Commit Message

Richard Earnshaw (lists) June 9, 2017, 12:53 p.m.
The assembler does not understand all the '+' options accepted by the
compiler.  The best solution to this is to simply strip the extensions
and just pass the raw architecture or cpu name through to the
assembler.  We will use .arch and .arch_extension directives anyway to
turn on or off individual features.  We already do something similar
for big.little combinations and this just extends this principle a bit
further.  This patch also fixes a possible bug by ensuring that the
limited string copy is correctly NUL-terminated.

While messing with this code I've also taken the opportunity to clean up
the duplicate definitions of EXTRA_SPEC_FUNCTIONS by moving it outside of
the ifdef wrapper.

	* config/arm/arm.h (BIG_LITTLE_SPEC): Delete macro.
	(ASM_REWRITE_SPEC_FUNCTIONS): New macro.
	(BIG_LITTLE_CPU_SPEC_FUNCTIONS): Delete macro.
	(ASM_CPU_SPEC): Rewrite.
	(MCPU_MTUNE_NATIVE_FUNCTIONS): New macro.
	(EXTRA_SPEC_FUNCTIONS): Move outside of ifdef.  Use
	MCPU_MTUNE_NATIVE_FUNCTIONS and ASM_REWRITE_SPEC_FUNCTIONS.  Remove
	reference to BIG_LITTLE_CPU_SPEC_FUNCTIONS.
	* common/config/arm/arm-common.c (arm_rewrite_selected_cpu): Ensure
	copied string is NUL-terminated.  Also strip any characters prefixed
	by '+'.
	(arm_rewrite_selected_arch): New function.
	(arm_rewrite_march): New function.
---
 gcc/common/config/arm/arm-common.c | 45 +++++++++++++++++++++++++++++++++++++-
 gcc/config/arm/arm.h               | 42 +++++++++++++++++------------------
 2 files changed, 65 insertions(+), 22 deletions(-)

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diff --git a/gcc/common/config/arm/arm-common.c b/gcc/common/config/arm/arm-common.c
index 7ecc68d..fd0c616 100644
--- a/gcc/common/config/arm/arm-common.c
+++ b/gcc/common/config/arm/arm-common.c
@@ -66,7 +66,7 @@  arm_except_unwind_info (struct gcc_options *opts)
 
 #define ARM_CPU_NAME_LENGTH 20
 
-/* Truncate NAME at the first '.' character seen, or return
+/* Truncate NAME at the first '.' or '+' character seen, or return
    NAME unmodified.  */
 
 const char *
@@ -76,12 +76,20 @@  arm_rewrite_selected_cpu (const char *name)
   char *arg_pos;
 
   strncpy (output_buf, name, ARM_CPU_NAME_LENGTH);
+  output_buf[ARM_CPU_NAME_LENGTH] = 0;
+
   arg_pos = strchr (output_buf, '.');
 
   /* If we found a '.' truncate the entry at that point.  */
   if (arg_pos)
     *arg_pos = '\0';
 
+  arg_pos = strchr (output_buf, '+');
+
+  /* If we found a '+' truncate the entry at that point.  */
+  if (arg_pos)
+    *arg_pos = '\0';
+
   return output_buf;
 }
 
@@ -98,6 +106,41 @@  arm_rewrite_mcpu (int argc, const char **argv)
   return arm_rewrite_selected_cpu (argv[argc - 1]);
 }
 
+/* Truncate NAME at the first '+' character seen, or return
+   NAME unmodified.  Similar to arm_rewrite_selected_cpu, but we must
+   preserve '.' as that is part of some architecture names.  */
+
+const char *
+arm_rewrite_selected_arch (const char *name)
+{
+  static char output_buf[ARM_CPU_NAME_LENGTH + 1] = {0};
+  char *arg_pos;
+
+  strncpy (output_buf, name, ARM_CPU_NAME_LENGTH);
+  output_buf[ARM_CPU_NAME_LENGTH] = 0;
+
+  arg_pos = strchr (output_buf, '+');
+
+  /* If we found a '+' truncate the entry at that point.  */
+  if (arg_pos)
+    *arg_pos = '\0';
+
+  return output_buf;
+}
+
+/* Called by the driver to rewrite a name passed to the -march
+   argument in preparation to be passed to the assembler.  The
+   names passed from the command line will be in ARGV, we want
+   to use the right-most argument, which should be in
+   ARGV[ARGC - 1].  ARGC should always be greater than 0.  */
+
+const char *
+arm_rewrite_march (int argc, const char **argv)
+{
+  gcc_assert (argc);
+  return arm_rewrite_selected_arch (argv[argc - 1]);
+}
+
 struct arm_arch_core_flag
 {
   const char *const name;
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h
index f9e4356..d398b99 100644
--- a/gcc/config/arm/arm.h
+++ b/gcc/config/arm/arm.h
@@ -2219,42 +2219,42 @@  extern int making_const_table;
    instruction.  */
 #define MAX_LDM_STM_OPS 4
 
-#define BIG_LITTLE_SPEC \
-   " %{mcpu=*:-mcpu=%:rewrite_mcpu(%{mcpu=*:%*})}"
-
 extern const char *arm_rewrite_mcpu (int argc, const char **argv);
-#define BIG_LITTLE_CPU_SPEC_FUNCTIONS \
-  { "rewrite_mcpu", arm_rewrite_mcpu },
+extern const char *arm_rewrite_march (int argc, const char **argv);
+#define ASM_CPU_SPEC_FUNCTIONS			\
+  { "rewrite_mcpu", arm_rewrite_mcpu },	\
+  { "rewrite_march", arm_rewrite_march },
 
-#define ASM_CPU_SPEC \
-   " %{mcpu=generic-*:-march=%*;"				\
-   "   :%{march=*:-march=%*}}"					\
-   BIG_LITTLE_SPEC
+#define ASM_CPU_SPEC							\
+  " %{mcpu=generic-*:-march=%:rewrite_march(%{mcpu=generic-*:%*});"	\
+  "   march=*:-march=%:rewrite_march(%{march=*:%*});"		\
+  "   mcpu=*:-mcpu=%:rewrite_mcpu(%{mcpu=*:%*})"			\
+  " }"
 
 extern const char *arm_target_thumb_only (int argc, const char **argv);
-#define TARGET_MODE_SPEC_FUNCTIONS					\
+#define TARGET_MODE_SPEC_FUNCTIONS			\
   { "target_mode_check", arm_target_thumb_only },
 
 /* -mcpu=native handling only makes sense with compiler running on
    an ARM chip.  */
 #if defined(__arm__)
 extern const char *host_detect_local_cpu (int argc, const char **argv);
-# define EXTRA_SPEC_FUNCTIONS						\
-  { "local_cpu_detect", host_detect_local_cpu },			\
-  BIG_LITTLE_CPU_SPEC_FUNCTIONS						\
-  TARGET_MODE_SPEC_FUNCTIONS
-
-# define MCPU_MTUNE_NATIVE_SPECS					\
-   " %{march=native:%<march=native %:local_cpu_detect(arch)}"		\
-   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"		\
+# define MCPU_MTUNE_NATIVE_FUNCTIONS			\
+  { "local_cpu_detect", host_detect_local_cpu },
+# define MCPU_MTUNE_NATIVE_SPECS				\
+   " %{march=native:%<march=native %:local_cpu_detect(arch)}"	\
+   " %{mcpu=native:%<mcpu=native %:local_cpu_detect(cpu)}"	\
    " %{mtune=native:%<mtune=native %:local_cpu_detect(tune)}"
 #else
+# define MCPU_MTUNE_NATIVE_FUNCTIONS
 # define MCPU_MTUNE_NATIVE_SPECS ""
-# define EXTRA_SPEC_FUNCTIONS						\
-	BIG_LITTLE_CPU_SPEC_FUNCTIONS					\
-	TARGET_MODE_SPEC_FUNCTIONS
 #endif
 
+# define EXTRA_SPEC_FUNCTIONS			\
+  MCPU_MTUNE_NATIVE_FUNCTIONS			\
+  ASM_CPU_SPEC_FUNCTIONS			\
+  TARGET_MODE_SPEC_FUNCTIONS
+
 /* Automatically add -mthumb for Thumb-only targets if mode isn't specified
    via the configuration option --with-mode or via the command line. The
    function target_mode_check is called to do the check with either: