2004-04-17 Paolo Bonzini <bonzini@gnu.org>

        * opts.c (decode_options): Do not enable flag_rename_registers
        and flag_web at -O3.
        * toplev.c (flag_rename_registers): Initialize
        flag_rename_registers and flag_web to
        AUTODETECT_FLAG_VAR_TRACKING.
        (default_debug_hooks): New global.
        (process_options): Initialize default_debug_hooks.  Warn if
        -fvar-tracking specified but not supported by the current
        debug format.  Do not run var tracking at -O0 or if not
        supported by the current debug format, even if
        -fvar-tracking was given.  If -fno-rename-registers
        is not specified, always run register renaming if var
        tracking is supported by the default debugging information
        format for the target, and we are at -O1 or higher; similarly
        for -fweb, but only at -O2 or higher.
        * doc/invoke.texi (Optimize Options): Document this.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@80789 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d097e38..0a29202 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,22 @@
+2004-04-17  Paolo Bonzini  <bonzini@gnu.org>
+
+       * opts.c (decode_options): Do not enable flag_rename_registers
+       and flag_web at -O3.
+       * toplev.c (flag_rename_registers): Initialize
+       flag_rename_registers and flag_web to
+       AUTODETECT_FLAG_VAR_TRACKING.
+       (default_debug_hooks): New global.
+       (process_options): Initialize default_debug_hooks.  Warn if
+       -fvar-tracking specified but not supported by the current
+       debug format.  Do not run var tracking at -O0 or if not
+       supported by the current debug format, even if
+       -fvar-tracking was given.  If -fno-rename-registers
+       is not specified, always run register renaming if var
+       tracking is supported by the default debugging information
+       format for the target, and we are at -O1 or higher; similarly
+       for -fweb, but only at -O2 or higher.
+       * doc/invoke.texi (Optimize Options): Document this.
+
 2004-04-17  Richard Sandiford  <rsandifo@redhat.com>
 
        * configure.ac (gcc_cv_ld_as_needed): Use AC_CACHE_CHECK.

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 60611f2..1529194 100644 (file)
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -4346,11 +4346,14 @@ Enabled at levels @option{-O2}, @option{-O3}.
 @opindex frename-registers
 Attempt to avoid false dependencies in scheduled code by making use
 of registers left over after register allocation.  This optimization
-will most benefit processors with lots of registers.  It can, however,
+will most benefit processors with lots of registers.  Depending on the
+debug information format adopted by the target, however, it can
 make debugging impossible, since variables will no longer stay in
 a ``home register''.
 
-Enabled at levels @option{-O3}.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os},
+on targets where the default format for debugging information supports
+variable tracking.
 
 @item -fweb
 @opindex fweb
@@ -4361,7 +4364,9 @@ passes, such as CSE, loop optimizer and trivial dead code remover.  It can,
 however, make debugging impossible, since variables will no longer stay in a
 ``home register''.
 
-Enabled at levels @option{-O3}.
+Enabled at levels @option{-O2}, @option{-O3}, @option{-Os},
+on targets where the default format for debugging information supports
+variable tracking.
 
 @item -fno-cprop-registers
 @opindex fno-cprop-registers

diff --git a/gcc/opts.c b/gcc/opts.c
index a2df41a..fb04b8f 100644 (file)
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -571,9 +571,7 @@ decode_options (unsigned int argc, const char **argv)
   if (optimize >= 3)
     {
       flag_inline_functions = 1;
-      flag_rename_registers = 1;
       flag_unswitch_loops = 1;
-      flag_web = 1;
       flag_gcse_after_reload = 1;
     }
 

diff --git a/gcc/toplev.c b/gcc/toplev.c
index 39b2ddf..faf177a 100644 (file)
--- a/gcc/toplev.c
+++ b/gcc/toplev.c
@@ -138,6 +138,10 @@ static const char **save_argv;
 
 const char *main_input_filename;
 
+/* Used to enable -fvar-tracking, -fweb and -frename-registers according
+   to optimize and default_debug_hooks in process_options ().  */
+#define AUTODETECT_FLAG_VAR_TRACKING 2
+
 /* Current position in real source file.  */
 
 location_t input_location;
@@ -177,6 +181,10 @@ int target_flags_explicit;
 
 const struct gcc_debug_hooks *debug_hooks;
 
+/* Debug hooks - target default.  */
+
+static const struct gcc_debug_hooks *default_debug_hooks;
+
 /* Other flags saying which kinds of debugging dump have been requested.  */
 
 int rtl_dump_and_exit;
@@ -258,9 +266,10 @@ int flag_reorder_blocks_and_partition = 0;
 
 int flag_reorder_functions = 0;
 
-/* Nonzero if registers should be renamed.  */
-
-int flag_rename_registers = 0;
+/* Nonzero if registers should be renamed.  When
+   flag_rename_registers == AUTODETECT_FLAG_VAR_TRACKING it will be set
+   according to optimize and default_debug_hooks in process_options ().  */
+int flag_rename_registers = AUTODETECT_FLAG_VAR_TRACKING;
 int flag_cprop_registers = 0;
 
 /* Nonzero for -pedantic switch: warn about anything
@@ -485,9 +494,11 @@ int flag_complex_divide_method = 0;
 
 int flag_syntax_only = 0;
 
-/* Nonzero means performs web construction pass.  */
+/* Nonzero means performs web construction pass.  When flag_web ==
+   AUTODETECT_FLAG_VAR_TRACKING it will be set according to optimize
+   and default_debug_hooks in process_options ().  */
 
-int flag_web;
+int flag_web = AUTODETECT_FLAG_VAR_TRACKING;
 
 /* Nonzero means perform loop optimizer.  */
 
@@ -800,8 +811,6 @@ int flag_unit_at_a_time = 0;
 /* Nonzero if we should track variables.  When
    flag_var_tracking == AUTODETECT_FLAG_VAR_TRACKING it will be set according
    to optimize, debug_info_level and debug_hooks in process_options ().  */
- 
-#define AUTODETECT_FLAG_VAR_TRACKING 2
 int flag_var_tracking = AUTODETECT_FLAG_VAR_TRACKING;
 
 /* Values of the -falign-* flags: how much to align labels in code.
@@ -2335,6 +2344,30 @@ process_options (void)
 
   /* Now we know write_symbols, set up the debug hooks based on it.
      By default we do nothing for debug output.  */
+  if (PREFERRED_DEBUGGING_TYPE == NO_DEBUG)
+    default_debug_hooks = &do_nothing_debug_hooks;
+#if defined(DBX_DEBUGGING_INFO)
+  else if (PREFERRED_DEBUGGING_TYPE == DBX_DEBUG)
+    default_debug_hooks = &dbx_debug_hooks;
+#endif
+#if defined(XCOFF_DEBUGGING_INFO)
+  else if (PREFERRED_DEBUGGING_TYPE == XCOFF_DEBUG)
+    default_debug_hooks = &xcoff_debug_hooks;
+#endif
+#ifdef SDB_DEBUGGING_INFO
+  else if (PREFERRED_DEBUGGING_TYPE == SDB_DEBUG)
+    default_debug_hooks = &sdb_debug_hooks;
+#endif
+#ifdef DWARF2_DEBUGGING_INFO
+  else if (PREFERRED_DEBUGGING_TYPE == DWARF2_DEBUG)
+    default_debug_hooks = &dwarf2_debug_hooks;
+#endif
+#ifdef VMS_DEBUGGING_INFO
+  else if (PREFERRED_DEBUGGING_TYPE == VMS_DEBUG
+          || PREFERRED_DEBUGGING_TYPE == VMS_AND_DWARF2_DEBUG)
+    default_debug_hooks = &vmsdbg_debug_hooks;
+#endif
+
   if (write_symbols == NO_DEBUG)
     debug_hooks = &do_nothing_debug_hooks;
 #if defined(DBX_DEBUGGING_INFO)
@@ -2362,15 +2395,34 @@ process_options (void)
           debug_type_names[write_symbols]);
 
   /* Now we know which debug output will be used so we can set
-     flag_var_tracking if user has not specified it.  */
-  if (flag_var_tracking == AUTODETECT_FLAG_VAR_TRACKING)
+     flag_var_tracking, flag_rename_registers and flag_web if the user has
+     not specified them.  */
+  if (debug_info_level < DINFO_LEVEL_NORMAL
+      || debug_hooks->var_location == do_nothing_debug_hooks.var_location)
     {
-      /* User has not specified -f(no-)var-tracking so autodetect it.  */
-      flag_var_tracking
-       = (optimize >= 1 && debug_info_level >= DINFO_LEVEL_NORMAL
-          && debug_hooks->var_location != do_nothing_debug_hooks.var_location);
+      if (flag_var_tracking == 1)
+        {
+         if (debug_info_level < DINFO_LEVEL_NORMAL)
+           warning ("variable tracking requested, but useless unless "
+                    "producing debug info");
+         else
+           warning ("variable tracking requested, but not supported "
+                    "by this debug format");
+       }
+      flag_var_tracking = 0;
     }
 
+  if (flag_rename_registers == AUTODETECT_FLAG_VAR_TRACKING)
+    flag_rename_registers = default_debug_hooks->var_location
+                           != do_nothing_debug_hooks.var_location;
+
+  if (flag_web == AUTODETECT_FLAG_VAR_TRACKING)
+    flag_web = optimize >= 2 && (default_debug_hooks->var_location
+                                != do_nothing_debug_hooks.var_location);
+
+  if (flag_var_tracking == AUTODETECT_FLAG_VAR_TRACKING)
+    flag_var_tracking = optimize >= 1;
+
   /* If auxiliary info generation is desired, open the output file.
      This goes in the same directory as the source file--unlike
      all the other output files.  */