merge some gcc-local(1) changes:

- disable -fident by default
- disable -fstrict-aliasing with -O2
- add support for -Wstack-larger-than-N (only for i386 and amd64 for now)

4 files changed, 30 insertions, 2 deletions

diff --git a/gnu/gcc/gcc/common.opt b/gnu/gcc/gcc/common.opt
index 23da331b927..360a4827b2c 100644
--- a/gnu/gcc/gcc/common.opt
+++ b/gnu/gcc/gcc/common.opt
@@ -97,6 +97,10 @@ Wlarger-than-
 Common RejectNegative Joined UInteger
 -Wlarger-than-<number>	Warn if an object is larger than <number> bytes
 
+Wstack-larger-than-
+Common RejectNegative Joined UInteger
+-Wstack-larger-than-<number> Warn if a function is using more than <number> bytes of stack space for their local variables.
+
 Wunsafe-loop-optimizations
 Common Var(warn_unsafe_loop_optimizations)
 Warn if the loop cannot be optimized due to nontrivial assumptions.
@@ -486,7 +490,7 @@ Enable guessing of branch probabilities
 ; On SVR4 targets, it also controls whether or not to emit a
 ; string identifying the compiler.
 fident
-Common Report Var(flag_no_ident,0)
+Common Report Var(flag_no_ident,1)
 Process #ident directives
 
 fif-conversion
diff --git a/gnu/gcc/gcc/config/i386/i386.c b/gnu/gcc/gcc/config/i386/i386.c
index 729dd408d7c..59d8220f7e6 100644
--- a/gnu/gcc/gcc/config/i386/i386.c
+++ b/gnu/gcc/gcc/config/i386/i386.c
@@ -1023,6 +1023,8 @@ struct ix86_frame
   HOST_WIDE_INT hard_frame_pointer_offset;
   HOST_WIDE_INT stack_pointer_offset;
 
+  HOST_WIDE_INT local_size;
+
   /* When save_regs_using_mov is set, emit prologue using
      move instead of push instructions.  */
   bool save_regs_using_mov;
@@ -5082,6 +5084,7 @@ ix86_compute_frame_layout (struct ix86_frame *frame)
   unsigned int preferred_alignment;
   HOST_WIDE_INT size = get_frame_size ();
 
+  frame->local_size = size;
   frame->nregs = ix86_nsaved_regs ();
   total_size = size;
 
@@ -5419,6 +5422,9 @@ ix86_expand_prologue (void)
       REG_NOTES (insn) = x;
     }
 
+  if (warn_stack_larger_than && frame.local_size > stack_larger_than_size)
+    warning (0, "stack usage is %d bytes", frame.local_size); 
+
   /* Note: AT&T enter does NOT have reversed args.  Enter is probably
      slower on all targets.  Also sdb doesn't like it.  */
 
diff --git a/gnu/gcc/gcc/flags.h b/gnu/gcc/gcc/flags.h
index 226fb603110..9dd81ef1f1b 100644
--- a/gnu/gcc/gcc/flags.h
+++ b/gnu/gcc/gcc/flags.h
@@ -109,6 +109,12 @@ extern void set_Wunused (int setting);
 extern bool warn_larger_than;
 extern HOST_WIDE_INT larger_than_size;
 
+/* Nonzero means warn about any function whose stack usage is larger
+   than N bytes.  The value N is in `stack_larger_than_size'.  */
+
+extern int warn_stack_larger_than;
+extern HOST_WIDE_INT stack_larger_than_size;
+
 /* Nonzero means warn about constructs which might not be strict
    aliasing safe.  */
 
diff --git a/gnu/gcc/gcc/opts.c b/gnu/gcc/gcc/opts.c
index 3c2abad7f8b..34d01c287e9 100644
--- a/gnu/gcc/gcc/opts.c
+++ b/gnu/gcc/gcc/opts.c
@@ -57,6 +57,11 @@ bool extra_warnings;
 bool warn_larger_than;
 HOST_WIDE_INT larger_than_size;
 
+/* Nonzero means warn about any function whose stack usage is larger
+   than N bytes.  The value N is in `stack_larger_than_size'.  */
+int warn_stack_larger_than;
+HOST_WIDE_INT stack_larger_than_size;
+
 /* Nonzero means warn about constructs which might not be
    strict-aliasing safe.  */
 int warn_strict_aliasing;
@@ -492,9 +497,11 @@ decode_options (unsigned int argc, const char **argv)
       flag_schedule_insns_after_reload = 1;
 #endif
       flag_regmove = 1;
-      flag_strict_aliasing = 1;
+      flag_strict_aliasing = 0;
       flag_strict_overflow = 1;
+#if !defined(OPENBSD_NATIVE) && !defined(OPENBSD_CROSS)
       flag_delete_null_pointer_checks = 1;
+#endif
       flag_reorder_blocks = 1;
       flag_reorder_functions = 1;
       flag_tree_store_ccp = 1;
@@ -720,6 +727,11 @@ common_handle_option (size_t scode, const char *arg, int value,
       warn_larger_than = value != -1;
       break;
 
+    case OPT_Wstack_larger_than_:
+      stack_larger_than_size = value;
+      warn_stack_larger_than = stack_larger_than_size != -1;
+      break;
+
     case OPT_Wstrict_aliasing:
     case OPT_Wstrict_aliasing_:
       warn_strict_aliasing = value;