re PR debug/54694 (internal compiler error: in dwarf2out_frame_debug_expr, at dwarf2out.c:2387)

PR debug/54694

Diagnose frame_pointer_required vs fixed hfp

From-SVN: r206647

gcc/ChangeLog

+2014-01-15  Richard Henderson <rth@redhat.com>
+
+	PR debug/54694
+	* reginfo.c (global_regs_decl): Globalize.
+	* rtl.h (global_regs_decl): Declare.
+	* ira.c (do_reload): Diagnose frame_pointer_needed and it
+	reserved via global_regs.
+
 2014-01-15  Teresa Johnson  <tejohnson@google.com>
 
 	* tree-ssa-sccvn.c (visit_reference_op_call): Handle NULL vdef.

gcc/ira.c

@@ -5532,6 +5532,18 @@ do_reload (void)
   if (need_dce && optimize)
     run_fast_dce ();
 
+  /* Diagnose uses of the hard frame pointer when it is used as a global
+     register.  Often we can get away with letting the user appropriate
+     the frame pointer, but we should let them know when code generation
+     makes that impossible.  */
+  if (global_regs[HARD_FRAME_POINTER_REGNUM] && frame_pointer_needed)
+    {
+      tree decl = global_regs_decl[HARD_FRAME_POINTER_REGNUM];
+      error_at (DECL_SOURCE_LOCATION (current_function_decl),
+                "frame pointer required, but reserved");
+      inform (DECL_SOURCE_LOCATION (decl), "for %qD", decl);
+    }
+
   timevar_pop (TV_IRA);
 }
 

gcc/reginfo.c

@@ -86,7 +86,7 @@ static const char initial_call_really_used_regs[] = CALL_REALLY_USED_REGISTERS;
 char global_regs[FIRST_PSEUDO_REGISTER];
 
 /* Declaration for the global register. */
-static tree GTY(()) global_regs_decl[FIRST_PSEUDO_REGISTER];
+tree global_regs_decl[FIRST_PSEUDO_REGISTER];
 
 /* Same information as REGS_INVALIDATED_BY_CALL but in regset form to be used
    in dataflow more conveniently.  */

gcc/rtl.h

@@ -2795,6 +2795,8 @@ extern void _fatal_insn (const char *, const_rtx, const char *, int, const char
 #define fatal_insn_not_found(insn) \
 	_fatal_insn_not_found (insn, __FILE__, __LINE__, __FUNCTION__)
 
+/* reginfo.c */
+extern tree GTY(()) global_regs_decl[FIRST_PSEUDO_REGISTER];
 
 
 #endif /* ! GCC_RTL_H */

gcc/testsuite/gcc.target/i386/pr54694.c

+/* { dg-do compile } */
+/* { dg-options "-O" } */
+
+register void *hfp __asm__("%ebp");	/* { dg-message "note: for" } */
+
+extern void g(void *);
+
+void f(int x)			/* { dg-error "frame pointer required" } */
+{
+  g(__builtin_alloca(x));
+}