decl.c (gnat_to_gnu_entity): Do not set "const" flag on "pure" Ada subprograms if...

	* decl.c (gnat_to_gnu_entity) <E_Procedure>: Do not set "const" flag
	on "pure" Ada subprograms if SJLJ exceptions are used.
	* trans.c (Handled_Sequence_Of_Statements_to_gnu): Set TREE_NO_WARNING
	on the declaration node of JMPBUF_SAVE.
	* utils.c (init_gigi_decls): Set DECL_IS_PURE on the declaration nodes
	of Get_Jmpbuf_Address_Soft and Get_GNAT_Exception.
	* utils2.c (build_call_0_expr): Do not set TREE_SIDE_EFFECTS.

From-SVN: r117299

diff --git a/gcc/ada/ChangeLog b/gcc/ada/ChangeLog
index d3466cfedde791aaa4f617033759da069d215826..d078714d1ae0eb06eda0e743ee42c26ecff9e677 100644 (file)
--- a/gcc/ada/ChangeLog
+++ b/gcc/ada/ChangeLog
@@ -1,3 +1,13 @@
+2006-09-28  Eric Botcazou  <ebotcazou@adacore.com>
+
+       * decl.c (gnat_to_gnu_entity) <E_Procedure>: Do not set "const" flag
+       on "pure" Ada subprograms if SJLJ exceptions are used.
+       * trans.c (Handled_Sequence_Of_Statements_to_gnu): Set TREE_NO_WARNING
+       on the declaration node of JMPBUF_SAVE.
+       * utils.c (init_gigi_decls): Set DECL_IS_PURE on the declaration nodes
+       of Get_Jmpbuf_Address_Soft and Get_GNAT_Exception.
+       * utils2.c (build_call_0_expr): Do not set TREE_SIDE_EFFECTS.
+
 2006-08-20  Laurent GUERBY  <laurent@guerby.net>
 
         PR ada/28716

diff --git a/gcc/ada/decl.c b/gcc/ada/decl.c
index c49e834bf49fc1632cce915cb46ece83359fdd89..fac6f2f06e3c73defedf6044a4a0b0f3cb478ed7 100644 (file)
--- a/gcc/ada/decl.c
+++ b/gcc/ada/decl.c
@@ -3768,11 +3768,20 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
        if (TREE_CODE (gnu_return_type) == VOID_TYPE)
          pure_flag = false;
 
+       /* The semantics of "pure" in Ada essentially matches that of "const"
+          in the back-end.  In particular, both properties are orthogonal to
+          the "nothrow" property.  But this is true only if the EH circuitry
+          is explicit in the internal representation of the back-end.  If we
+          are to completely hide the EH circuitry from it, we need to declare
+          that calls to pure Ada subprograms that can throw have side effects
+          since they can trigger an "abnormal" transfer of control flow; thus
+          they can be neither "const" nor "pure" in the back-end sense.  */
        gnu_type
          = build_qualified_type (gnu_type,
-                                 (TYPE_QUALS (gnu_type)
-                                  | (TYPE_QUAL_CONST * pure_flag)
-                                  | (TYPE_QUAL_VOLATILE * volatile_flag)));
+                                 TYPE_QUALS (gnu_type)
+                                 | (Exception_Mechanism == Back_End_Exceptions
+                                    ? TYPE_QUAL_CONST * pure_flag : 0)
+                                 | (TYPE_QUAL_VOLATILE * volatile_flag));
 
        Sloc_to_locus (Sloc (gnat_entity), &input_location);
 
@@ -3841,6 +3850,7 @@ gnat_to_gnu_entity (Entity_Id gnat_entity, tree gnu_expr, int definition)
                                            inline_flag, public_flag,
                                            extern_flag, attr_list,
                                            gnat_entity);
+
            DECL_STUBBED_P (gnu_decl)
              = Convention (gnat_entity) == Convention_Stubbed;
          }

diff --git a/gcc/ada/trans.c b/gcc/ada/trans.c
index 7fecc6feb9daa551062e82c609690639cad05045..fe820bf0ccffed47bdb23d7811220ca22c0ca731 100644 (file)
--- a/gcc/ada/trans.c
+++ b/gcc/ada/trans.c
@@ -2167,6 +2167,11 @@ Handled_Sequence_Of_Statements_to_gnu (Node_Id gnat_node)
                                          build_call_0_expr (get_jmpbuf_decl),
                                          false, false, false, false, NULL,
                                          gnat_node);
+      /* The __builtin_setjmp receivers will immediately reinstall it.  Now
+        because of the unstructured form of EH used by setjmp_longjmp, there
+        might be forward edges going to __builtin_setjmp receivers on which
+        it is uninitialized, although they will never be actually taken.  */
+      TREE_NO_WARNING (gnu_jmpsave_decl) = 1;
       gnu_jmpbuf_decl = create_var_decl (get_identifier ("JMP_BUF"),
                                         NULL_TREE, jmpbuf_type,
                                         NULL_TREE, false, false, false, false,

diff --git a/gcc/ada/utils.c b/gcc/ada/utils.c
index 4358547883e6a157d7660fa9a183e9b1a04e2c78..3874e39bb8c20b5d2ba25d528a0bcee4ea92a50d 100644 (file)
--- a/gcc/ada/utils.c
+++ b/gcc/ada/utils.c
@@ -518,6 +518,8 @@ init_gigi_decls (tree long_long_float_type, tree exception_type)
     (get_identifier ("system__soft_links__get_jmpbuf_address_soft"),
      NULL_TREE, build_function_type (jmpbuf_ptr_type, NULL_TREE),
      NULL_TREE, false, true, true, NULL, Empty);
+  /* Avoid creating superfluous edges to __builtin_setjmp receivers.  */
+  DECL_IS_PURE (get_jmpbuf_decl) = 1;
 
   set_jmpbuf_decl
     = create_subprog_decl
@@ -534,6 +536,8 @@ init_gigi_decls (tree long_long_float_type, tree exception_type)
      NULL_TREE,
      build_function_type (build_pointer_type (except_type_node), NULL_TREE),
      NULL_TREE, false, true, true, NULL, Empty);
+  /* Avoid creating superfluous edges to __builtin_setjmp receivers.  */
+  DECL_IS_PURE (get_excptr_decl) = 1;
 
   /* Functions that raise exceptions. */
   raise_nodefer_decl

diff --git a/gcc/ada/utils2.c b/gcc/ada/utils2.c
index 65837bb015133cdf10267dd85fb8c6833e74c5b0..ffca59798caa5b2b3b9eae8664cb47109a5b3529 100644 (file)
--- a/gcc/ada/utils2.c
+++ b/gcc/ada/utils2.c
@@ -1431,7 +1431,8 @@ build_call_0_expr (tree fundecl)
                      build_unary_op (ADDR_EXPR, NULL_TREE, fundecl),
                      NULL_TREE, NULL_TREE);
 
-  TREE_SIDE_EFFECTS (call) = 1;
+  /* We rely on build3 to compute TREE_SIDE_EFFECTS.  This makes it possible
+     to propagate the DECL_IS_PURE flag on parameterless functions.  */
 
   return call;
 }