Re: reliably telling whether a data object is in a RO, RW or ?? section

[Alexandre Oliva <aoliva at redhat dot com>]

On Oct  1, 2003, Richard Henderson <rth@redhat.com> wrote:

> On Mon, Sep 29, 2003 at 07:19:33PM -0300, Alexandre Oliva wrote:
>> * varasm.c (output_addressed_constants): Add boolean argument to
>> control whether to actually output the constant or just compute
>> reloc.  Adjust all callers.

> I think I'd much prefer that the two functions be split apart.

How about this?  Bootstrapped on i686-pc-linux-gnu

Index: gcc/ChangeLog
from  Alexandre Oliva  <aoliva@redhat.com>

	* output.h (compute_reloc_for_constant): Declare.
	* varasm.c (compute_reloc_for_constant): Extract from...
	(output_addressed_constants): ... here.  Adjust all callers.

	* config/frv/frv.h (PREDICATE_CODES): Added
Index: gcc/output.h
===================================================================
RCS file: /cvs/gcc/gcc/gcc/output.h,v
retrieving revision 1.132
diff -u -p -r1.132 output.h
--- gcc/output.h 29 Sep 2003 22:07:39 -0000 1.132
+++ gcc/output.h 1 Oct 2003 21:41:55 -0000
@@ -437,6 +437,10 @@ extern rtx this_is_asm_operands;
 extern bool decl_readonly_section (tree, int);
 extern bool decl_readonly_section_1 (tree, int, int);
 
+/* This can be used to compute RELOC for the function above, when
+   given a constant expression.  */
+extern int compute_reloc_for_constant (tree);
+
 /* User label prefix in effect for this compilation.  */
 extern const char *user_label_prefix;
 
Index: gcc/varasm.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/varasm.c,v
retrieving revision 1.388
diff -u -p -r1.388 varasm.c
--- gcc/varasm.c 29 Sep 2003 21:29:11 -0000 1.388
+++ gcc/varasm.c 1 Oct 2003 21:41:58 -0000
@@ -154,7 +154,7 @@ static struct pool_constant *find_pool_c
 static void mark_constant_pool (void);
 static void mark_constants (rtx);
 static int mark_constant (rtx *current_rtx, void *data);
-static int output_addressed_constants (tree);
+static void output_addressed_constants (tree);
 static unsigned HOST_WIDE_INT array_size_for_constructor (tree);
 static unsigned min_align (unsigned, unsigned);
 static void output_constructor (tree, unsigned HOST_WIDE_INT, unsigned int);
@@ -1459,7 +1459,10 @@ assemble_variable (tree decl, int top_le
   if (DECL_INITIAL (decl) == error_mark_node)
     reloc = contains_pointers_p (TREE_TYPE (decl)) ? 3 : 0;
   else if (DECL_INITIAL (decl))
-    reloc = output_addressed_constants (DECL_INITIAL (decl));
+    {
+      reloc = compute_reloc_for_constant (DECL_INITIAL (decl));
+      output_addressed_constants (DECL_INITIAL (decl));
+    }
   resolve_unique_section (decl, reloc, flag_data_sections);
 
   /* Handle uninitialized definitions.  */
@@ -2501,7 +2504,7 @@ output_constant_def_contents (rtx symbol
 
   /* Make sure any other constants whose addresses appear in EXP
      are assigned label numbers.  */
-  int reloc = output_addressed_constants (exp);
+  int reloc = compute_reloc_for_constant (exp);
 
   /* Align the location counter as required by EXP's data type.  */
   int align = TYPE_ALIGN (TREE_TYPE (exp));
@@ -2509,6 +2512,8 @@ output_constant_def_contents (rtx symbol
   align = CONSTANT_ALIGNMENT (exp, align);
 #endif
 
+  output_addressed_constants (exp);
+
   /* We are no longer deferring this constant.  */
   TREE_ASM_WRITTEN (exp) = 1;
 
@@ -3329,12 +3334,10 @@ mark_constant (rtx *current_rtx, void *d
   return 0;
 }
 
-/* Find all the constants whose addresses are referenced inside of EXP,
-   and make sure assembler code with a label has been output for each one.
-   Indicate whether an ADDR_EXPR has been encountered.  */
+/* Determine what kind of relocations EXP may need.  */
 
-static int
-output_addressed_constants (tree exp)
+int
+compute_reloc_for_constant (tree exp)
 {
   int reloc = 0, reloc2;
   tree tem;
@@ -3354,10 +3357,6 @@ output_addressed_constants (tree exp)
 	   tem = TREE_OPERAND (tem, 0))
 	;
 
-      if (TREE_CODE_CLASS (TREE_CODE (tem)) == 'c'
-	  || TREE_CODE (tem) == CONSTRUCTOR)
-	output_constant_def (tem, 0);
-
       if (TREE_PUBLIC (tem))
 	reloc |= 2;
       else
@@ -3365,13 +3364,13 @@ output_addressed_constants (tree exp)
       break;
 
     case PLUS_EXPR:
-      reloc = output_addressed_constants (TREE_OPERAND (exp, 0));
-      reloc |= output_addressed_constants (TREE_OPERAND (exp, 1));
+      reloc = compute_reloc_for_constant (TREE_OPERAND (exp, 0));
+      reloc |= compute_reloc_for_constant (TREE_OPERAND (exp, 1));
       break;
 
     case MINUS_EXPR:
-      reloc = output_addressed_constants (TREE_OPERAND (exp, 0));
-      reloc2 = output_addressed_constants (TREE_OPERAND (exp, 1));
+      reloc = compute_reloc_for_constant (TREE_OPERAND (exp, 0));
+      reloc2 = compute_reloc_for_constant (TREE_OPERAND (exp, 1));
       /* The difference of two local labels is computable at link time.  */
       if (reloc == 1 && reloc2 == 1)
 	reloc = 0;
@@ -3382,13 +3381,13 @@ output_addressed_constants (tree exp)
     case NOP_EXPR:
     case CONVERT_EXPR:
     case NON_LVALUE_EXPR:
-      reloc = output_addressed_constants (TREE_OPERAND (exp, 0));
+      reloc = compute_reloc_for_constant (TREE_OPERAND (exp, 0));
       break;
 
     case CONSTRUCTOR:
       for (tem = CONSTRUCTOR_ELTS (exp); tem; tem = TREE_CHAIN (tem))
 	if (TREE_VALUE (tem) != 0)
-	  reloc |= output_addressed_constants (TREE_VALUE (tem));
+	  reloc |= compute_reloc_for_constant (TREE_VALUE (tem));
 
       break;
 
@@ -3396,6 +3395,58 @@ output_addressed_constants (tree exp)
       break;
     }
   return reloc;
+}
+
+/* Find all the constants whose addresses are referenced inside of EXP,
+   and make sure assembler code with a label has been output for each one.
+   Indicate whether an ADDR_EXPR has been encountered.  */
+
+static void
+output_addressed_constants (tree exp)
+{
+  tree tem;
+
+  /* Give the front-end a chance to convert VALUE to something that
+     looks more like a constant to the back-end.  */
+  exp = (*lang_hooks.expand_constant) (exp);
+
+  switch (TREE_CODE (exp))
+    {
+    case ADDR_EXPR:
+    case FDESC_EXPR:
+      /* Go inside any operations that get_inner_reference can handle and see
+	 if what's inside is a constant: no need to do anything here for
+	 addresses of variables or functions.  */
+      for (tem = TREE_OPERAND (exp, 0); handled_component_p (tem);
+	   tem = TREE_OPERAND (tem, 0))
+	;
+
+      if (TREE_CODE_CLASS (TREE_CODE (tem)) == 'c'
+	  || TREE_CODE (tem) == CONSTRUCTOR)
+	output_constant_def (tem, 0);
+      break;
+
+    case PLUS_EXPR:
+    case MINUS_EXPR:
+      output_addressed_constants (TREE_OPERAND (exp, 1));
+      /* Fall through.  */
+
+    case NOP_EXPR:
+    case CONVERT_EXPR:
+    case NON_LVALUE_EXPR:
+      output_addressed_constants (TREE_OPERAND (exp, 0));
+      break;
+
+    case CONSTRUCTOR:
+      for (tem = CONSTRUCTOR_ELTS (exp); tem; tem = TREE_CHAIN (tem))
+	if (TREE_VALUE (tem) != 0)
+	  output_addressed_constants (TREE_VALUE (tem));
+
+      break;
+
+    default:
+      break;
+    }
 }
 
 /* Return nonzero if VALUE is a valid constant-valued expression

-- 
Alexandre Oliva   Enjoy Guarana', see http://www.ic.unicamp.br/~oliva/
Red Hat GCC Developer                 aoliva@{redhat.com, gcc.gnu.org}
CS PhD student at IC-Unicamp        oliva@{lsd.ic.unicamp.br, gnu.org}
Free Software Evangelist                Professional serial bug killer