On 11/23/22 10:28, Jason Merrill wrote:
On 11/22/22 15:25, Jason Merrill wrote:
On 11/20/22 12:06, Bernhard Reutner-Fischer wrote:
Hi Jason!
The "meh" of result-decl-plugin-test-2.C should likely be omitted,
grokdeclarator would need some changes to add richloc hints and we
would not
be able to make a reliable guess what to remove precisely.
C.f. /* Check all other uses of type modifiers. */
Furthermore it is unrelated to DECL_RESULT so not of direct interest
here. The other tests in test-2.C, f() and huh() should work though.
I don't know if it's acceptable to change ipa-pure-const to make the
missing noreturn warning more precise and emit a fixit-hint. At least it
would be a real test for the DECL_RESULT and would spare us the plugin.
The main problem I see with that change is that the syntax of the
fixit might be wrong for non-C-family front-ends.
Here's a version of the patch that fixes template/method handling, and
adjusts -Waggregate-return as well:
Actually, that broke some of the spaceship tests, fixed by this version:
Here's what I'm applying:
From d19aa6af6634b1e97f38431ad091f3b3f12baf2f Mon Sep 17 00:00:00 2001
From: Bernhard Reutner-Fischer <rep.dot....@gmail.com>
Date: Sun, 20 Nov 2022 18:06:04 +0100
Subject: [PATCH] c++: Set the locus of the function result decl
To: gcc-patches@gcc.gnu.org
gcc/cp/ChangeLog:
* decl.cc (grokdeclarator): Build RESULT_DECL.
(start_preparsed_function): Copy location from template.
* semantics.cc (apply_deduced_return_type): Handle
arg != current_function_decl.
* method.cc (implicitly_declare_fn): Use it.
gcc/ChangeLog:
* function.cc (init_function_start): Use DECL_RESULT location
for -Waggregate-return warning.
gcc/testsuite/ChangeLog:
* g++.dg/diagnostic/return-type-loc1.C: New test.
Co-authored-by: Jason Merrill <ja...@redhat.com>
---
gcc/cp/decl.cc | 25 +++++++++++++++++--
gcc/cp/method.cc | 2 +-
gcc/cp/semantics.cc | 15 ++++++-----
gcc/function.cc | 3 ++-
.../g++.dg/diagnostic/return-type-loc1.C | 20 +++++++++++++++
5 files changed, 53 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/diagnostic/return-type-loc1.C
diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 238e72f90da..508156309d9 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -14772,6 +14772,19 @@ grokdeclarator (const cp_declarator *declarator,
else if (constinit_p)
DECL_DECLARED_CONSTINIT_P (decl) = true;
}
+ else if (TREE_CODE (decl) == FUNCTION_DECL)
+ {
+ /* If we saw a return type, record its location. */
+ location_t loc = declspecs->locations[ds_type_spec];
+ if (loc != UNKNOWN_LOCATION)
+ {
+ tree restype = TREE_TYPE (TREE_TYPE (decl));
+ tree resdecl = build_decl (loc, RESULT_DECL, 0, restype);
+ DECL_ARTIFICIAL (resdecl) = 1;
+ DECL_IGNORED_P (resdecl) = 1;
+ DECL_RESULT (decl) = resdecl;
+ }
+ }
/* Record constancy and volatility on the DECL itself . There's
no need to do this when processing a template; we'll do this
@@ -17326,9 +17339,17 @@ start_preparsed_function (tree decl1, tree attrs, int flags)
if (DECL_RESULT (decl1) == NULL_TREE)
{
- tree resdecl;
+ /* In a template instantiation, copy the return type location. When
+ parsing, the location will be set in grokdeclarator. */
+ location_t loc = input_location;
+ if (DECL_TEMPLATE_INSTANTIATION (decl1))
+ {
+ tree tmpl = template_for_substitution (decl1);
+ if (tree res = DECL_RESULT (DECL_TEMPLATE_RESULT (tmpl)))
+ loc = DECL_SOURCE_LOCATION (res);
+ }
- resdecl = build_decl (input_location, RESULT_DECL, 0, restype);
+ tree resdecl = build_decl (loc, RESULT_DECL, 0, restype);
DECL_ARTIFICIAL (resdecl) = 1;
DECL_IGNORED_P (resdecl) = 1;
DECL_RESULT (decl1) = resdecl;
diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
index 1e962b6e3b1..7b4d5a59823 100644
--- a/gcc/cp/method.cc
+++ b/gcc/cp/method.cc
@@ -3079,7 +3079,7 @@ implicitly_declare_fn (special_function_kind kind, tree type,
{
fn = copy_operator_fn (pattern_fn, EQ_EXPR);
DECL_ARTIFICIAL (fn) = 1;
- TREE_TYPE (fn) = change_return_type (boolean_type_node, TREE_TYPE (fn));
+ apply_deduced_return_type (fn, boolean_type_node);
return fn;
}
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 9401b35a789..ab52e56d6c1 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12325,24 +12325,23 @@ apply_deduced_return_type (tree fco, tree return_type)
/* We already have a DECL_RESULT from start_preparsed_function.
Now we need to redo the work it and allocate_struct_function
did to reflect the new type. */
- gcc_assert (current_function_decl == fco);
- result = build_decl (input_location, RESULT_DECL, NULL_TREE,
+ result = build_decl (DECL_SOURCE_LOCATION (result), RESULT_DECL, NULL_TREE,
TYPE_MAIN_VARIANT (return_type));
DECL_ARTIFICIAL (result) = 1;
DECL_IGNORED_P (result) = 1;
cp_apply_type_quals_to_decl (cp_type_quals (return_type),
result);
-
DECL_RESULT (fco) = result;
if (!processing_template_decl)
- {
- bool aggr = aggregate_value_p (result, fco);
+ if (function *fun = DECL_STRUCT_FUNCTION (fco))
+ {
+ bool aggr = aggregate_value_p (result, fco);
#ifdef PCC_STATIC_STRUCT_RETURN
- cfun->returns_pcc_struct = aggr;
+ fun->returns_pcc_struct = aggr;
#endif
- cfun->returns_struct = aggr;
- }
+ fun->returns_struct = aggr;
+ }
}
/* DECL is a local variable or parameter from the surrounding scope of a
diff --git a/gcc/function.cc b/gcc/function.cc
index 9c8773bbc59..dc333c27e92 100644
--- a/gcc/function.cc
+++ b/gcc/function.cc
@@ -4997,7 +4997,8 @@ init_function_start (tree subr)
/* Warn if this value is an aggregate type,
regardless of which calling convention we are using for it. */
if (AGGREGATE_TYPE_P (TREE_TYPE (DECL_RESULT (subr))))
- warning (OPT_Waggregate_return, "function returns an aggregate");
+ warning_at (DECL_SOURCE_LOCATION (DECL_RESULT (subr)),
+ OPT_Waggregate_return, "function returns an aggregate");
}
/* Expand code to verify the stack_protect_guard. This is invoked at
diff --git a/gcc/testsuite/g++.dg/diagnostic/return-type-loc1.C b/gcc/testsuite/g++.dg/diagnostic/return-type-loc1.C
new file mode 100644
index 00000000000..f96179ed4d5
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/return-type-loc1.C
@@ -0,0 +1,20 @@
+// { dg-do compile { target c++11 } }
+// { dg-additional-options -Waggregate-return }
+
+struct B { int i,j; };
+
+template <class T>
+struct A
+{
+ template <class U>
+ U // { dg-warning "aggregate" }
+ f() { return {}; }
+};
+
+int main()
+{
+ A<int>().f<B>(); // { dg-warning "aggregate" }
+}
+
+B // { dg-warning "aggregate" }
+g() { return {}; }
--
2.31.1
