Now that we have constexpr constructors, having a non-trivial
constructor no longer precludes a variable being TREE_READONLY. The
front end will clear TREE_READONLY if the variable requires non-constant
initialization.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit bd0343de0277ae5d66f60a42d6479df0161fc075
Author: Jason Merrill <ja...@redhat.com>
Date: Fri Jul 8 09:32:45 2011 -0400
PR c++/49673
gcc/c-family/
* c-common.c (c_apply_type_quals_to_decl): Don't check
TYPE_NEEDS_CONSTRUCTING.
gcc/cp/
* typeck.c (cp_apply_type_quals_to_decl): Don't check
TYPE_NEEDS_CONSTRUCTING.
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 67291de..f61b9cc 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -4058,14 +4058,11 @@ c_apply_type_quals_to_decl (int type_quals, tree decl)
if (type == error_mark_node)
return;
- if (((type_quals & TYPE_QUAL_CONST)
- || (type && TREE_CODE (type) == REFERENCE_TYPE))
- /* An object declared 'const' is only readonly after it is
- initialized. We don't have any way of expressing this currently,
- so we need to be conservative and unset TREE_READONLY for types
- with constructors. Otherwise aliasing code will ignore stores in
- an inline constructor. */
- && !(type && TYPE_NEEDS_CONSTRUCTING (type)))
+ if ((type_quals & TYPE_QUAL_CONST)
+ || (type && TREE_CODE (type) == REFERENCE_TYPE))
+ /* We used to check TYPE_NEEDS_CONSTRUCTING here, but now a constexpr
+ constructor can produce constant init, so rely on the front end to
+ clear TREE_READONLY if the variable has non-constant init. */
TREE_READONLY (decl) = 1;
if (type_quals & TYPE_QUAL_VOLATILE)
{
diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 2acb18e..f0d68c3 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -8127,12 +8127,12 @@ cp_apply_type_quals_to_decl (int type_quals, tree decl)
&& type_quals != TYPE_UNQUALIFIED));
/* Avoid setting TREE_READONLY incorrectly. */
- if (/* If the object has a constructor, the constructor may modify
- the object. */
- TYPE_NEEDS_CONSTRUCTING (type)
- /* If the type isn't complete, we don't know yet if it will need
+ /* We used to check TYPE_NEEDS_CONSTRUCTING here, but now a constexpr
+ constructor can produce constant init, so rely on cp_finish_decl to
+ clear TREE_READONLY if the variable has non-constant init. */
+ if (/* If the type isn't complete, we don't know yet if it will need
constructing. */
- || !COMPLETE_TYPE_P (type)
+ !COMPLETE_TYPE_P (type)
/* If the type has a mutable component, that component might be
modified. */
|| TYPE_HAS_MUTABLE_P (type))
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-rom.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-rom.C
new file mode 100644
index 0000000..e2edb2e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-rom.C
@@ -0,0 +1,11 @@
+// PR c++/49673: check that test_data goes into .rodata
+// { dg-options -std=c++0x }
+// { dg-final { scan-assembler "rodata" } }
+
+struct Data
+{
+ int i;
+ constexpr Data(int i = 0) : i(i+1) {}
+};
+
+extern const Data test_data = { 1 };
