[PATCH] c++: Member initializer list diagnostic locations [PR94024]

Patrick Palka ppalka@redhat.com
Mon Aug 3 18:49:29 GMT 2020


On Mon, 3 Aug 2020, Jason Merrill wrote:

> On 8/3/20 10:14 AM, Patrick Palka wrote:
> > This patch preserves the source locations of each node in a member
> > initializer list so that during processing of the list we can set
> > input_location appropriately for generally more accurate diagnostic
> > locations.  Since TREE_LIST nodes are tcc_exceptional, they can't have
> > source locations, so we instead store the location in a dummy
> > tcc_expression node within the TREE_TYPE of the list node.
> 
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK to
> > commit?
> > 
> > gcc/cp/ChangeLog:
> > 
> > 	PR c++/94024
> > 	* init.c (sort_mem_initializers): Preserve TREE_TYPE of the
> > 	member initializer list node.
> > 	(emit_mem_initializers): Set input_location when performing each
> > 	member initialization.
> > 	* parser.c (cp_parser_mem_initializer_list): Attach the source
> > 	location of this initializer to a dummy EMPTY_CLASS_EXPR within
> > 	the TREE_TYPE of the list node.
> > 	* pt.c (tsubst_initializer_list): Preserve TREE_TYPE of the
> > 	member initializer list node.
> > 
> > gcc/testsuite/ChangeLog:
> > 
> > 	PR c++/94024
> > 	* g++.dg/diagnostic/mem-init1.C: New test.
> > ---
> >   gcc/cp/init.c                               |  6 +++++
> >   gcc/cp/parser.c                             |  8 ++++++
> >   gcc/cp/pt.c                                 |  3 +++
> >   gcc/testsuite/g++.dg/diagnostic/mem-init1.C | 29 +++++++++++++++++++++
> >   4 files changed, 46 insertions(+)
> >   create mode 100644 gcc/testsuite/g++.dg/diagnostic/mem-init1.C
> > 
> > diff --git a/gcc/cp/init.c b/gcc/cp/init.c
> > index cb9bd2dbfba..3f089404cf2 100644
> > --- a/gcc/cp/init.c
> > +++ b/gcc/cp/init.c
> > @@ -1151,6 +1151,8 @@ sort_mem_initializers (tree t, tree mem_inits)
> >           /* Record the initialization.  */
> >         TREE_VALUE (subobject_init) = TREE_VALUE (init);
> > +      /* Carry over the dummy TREE_TYPE node containing the source
> > location.  */
> > +      TREE_TYPE (subobject_init) = TREE_TYPE (init);
> >         next_subobject = subobject_init;
> >       }
> >   @@ -1367,6 +1369,10 @@ emit_mem_initializers (tree mem_inits)
> >     /* Initialize the data members.  */
> >     while (mem_inits)
> >       {
> > +      /* If this initializer was explicitly provided, then the dummy
> > TREE_TYPE
> > +	 node contains the source location.  */
> > +      iloc_sentinel ils (EXPR_LOCATION (TREE_TYPE (mem_inits)));
> > +
> >         perform_member_init (TREE_PURPOSE (mem_inits),
> >   			   TREE_VALUE (mem_inits));
> >         mem_inits = TREE_CHAIN (mem_inits);
> > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
> > index ab088874ba7..2f9b8786121 100644
> > --- a/gcc/cp/parser.c
> > +++ b/gcc/cp/parser.c
> > @@ -15326,6 +15326,14 @@ cp_parser_mem_initializer_list (cp_parser* parser)
> >   	{
> >   	  TREE_CHAIN (mem_initializer) = mem_initializer_list;
> >   	  mem_initializer_list = mem_initializer;
> > +
> > +	  /* We can't attach the source location of this initializer directly
> > to
> > +	     the list node, so we instead attach it to a dummy
> > EMPTY_CLASS_EXPR
> > +	     within the TREE_TYPE of the list node.  */
> > +	  TREE_TYPE (mem_initializer) = build0 (EMPTY_CLASS_EXPR, NULL_TREE);
> > +	  SET_EXPR_LOCATION (TREE_TYPE (mem_initializer),
> > +			     make_location (token->location,
> > +					    token->location, input_location));
> 
> Why not do this in cp_parser_mem_initializer?
> 
> Also, use parser->lexer for the last argument to make_location.

That's a much better spot for it :) Done and done.  Does the following
look OK after testing completes?

-- >8 --

Subject: [PATCH] c++: Member initializer list diagnostic locations [PR94024]

This patch preserves the source locations of each node in a member
initializer list so that during processing of the list we can set
input_location appropriately for generally more accurate diagnostic
locations.  Since TREE_LIST nodes are tcc_exceptional, they can't have
source locations, so we instead store the location in a dummy
tcc_expression node within the TREE_TYPE of the list node.

Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK to
commit?

gcc/cp/ChangeLog:

	PR c++/94024
	* init.c (sort_mem_initializers): Preserve TREE_TYPE of the
	member initializer list node.
	(emit_mem_initializers): Set input_location when performing each
	member initialization.
	* parser.c (cp_parser_mem_initializer): Attach the source
	location of this initializer to a dummy EMPTY_CLASS_EXPR
	within the TREE_TYPE of the list node.
	* pt.c (tsubst_initializer_list): Preserve TREE_TYPE of the
	member initializer list node.

gcc/testsuite/ChangeLog:

	PR c++/94024
	* g++.dg/diagnostic/mem-init1.C: New test.
---
 gcc/cp/init.c                               |  6 +++++
 gcc/cp/parser.c                             | 13 ++++++++-
 gcc/cp/pt.c                                 |  3 +++
 gcc/testsuite/g++.dg/diagnostic/mem-init1.C | 29 +++++++++++++++++++++
 4 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/diagnostic/mem-init1.C

diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index cb9bd2dbfba..3f089404cf2 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1151,6 +1151,8 @@ sort_mem_initializers (tree t, tree mem_inits)
 
       /* Record the initialization.  */
       TREE_VALUE (subobject_init) = TREE_VALUE (init);
+      /* Carry over the dummy TREE_TYPE node containing the source location.  */
+      TREE_TYPE (subobject_init) = TREE_TYPE (init);
       next_subobject = subobject_init;
     }
 
@@ -1367,6 +1369,10 @@ emit_mem_initializers (tree mem_inits)
   /* Initialize the data members.  */
   while (mem_inits)
     {
+      /* If this initializer was explicitly provided, then the dummy TREE_TYPE
+	 node contains the source location.  */
+      iloc_sentinel ils (EXPR_LOCATION (TREE_TYPE (mem_inits)));
+
       perform_member_init (TREE_PURPOSE (mem_inits),
 			   TREE_VALUE (mem_inits));
       mem_inits = TREE_CHAIN (mem_inits);
diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index ab088874ba7..8b11e478c83 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -15411,7 +15411,18 @@ cp_parser_mem_initializer (cp_parser* parser)
 
   in_base_initializer = 0;
 
-  return member ? build_tree_list (member, expression_list) : error_mark_node;
+  if (!member)
+    return error_mark_node;
+
+  tree node = build_tree_list (member, expression_list);
+  /* We can't attach the source location of this initializer directly to
+     the list node, so we instead attach it to a dummy EMPTY_CLASS_EXPR
+     within the TREE_TYPE of the list node.  */
+  TREE_TYPE (node) = build0 (EMPTY_CLASS_EXPR, NULL_TREE);
+  SET_EXPR_LOCATION (TREE_TYPE (node),
+		     make_location (token->location,
+				    token->location, parser->lexer));
+  return node;
 }
 
 /* Parse a mem-initializer-id.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 524c0bfe2d6..721eb5262d6 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -26014,6 +26014,9 @@ tsubst_initializer_list (tree t, tree argvec)
           if (decl)
             {
               init = build_tree_list (decl, init);
+	      /* Carry over the dummy TREE_TYPE node containing the source
+		 location.  */
+	      TREE_TYPE (init) = TREE_TYPE (t);
               TREE_CHAIN (init) = inits;
               inits = init;
             }
diff --git a/gcc/testsuite/g++.dg/diagnostic/mem-init1.C b/gcc/testsuite/g++.dg/diagnostic/mem-init1.C
new file mode 100644
index 00000000000..b749c72cd8b
--- /dev/null
+++ b/gcc/testsuite/g++.dg/diagnostic/mem-init1.C
@@ -0,0 +1,29 @@
+// PR c++/94024
+// { dg-do compile }
+
+struct A {
+    A()
+    : a()       // { dg-error "reference type" }
+    , b(1)      // { dg-error "incompatible" }
+    , c(0)      // { dg-bogus "" }
+    {}
+
+    int &a;
+    int b[1];
+    char c;
+};
+
+template<typename T, typename U>
+struct B {
+    B()
+    : a()       // { dg-error "reference type" }
+    , b(1)      // { dg-error "incompatible" }
+    , c(0)      // { dg-bogus "" }
+    {}
+
+    T a;
+    U b;
+    char c;
+};
+
+B<int&, int[1]> b;
-- 
2.28.0.89.g85b4e0a6dc



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