Re: [PATCH v3] gdb: CTF support

[Andrew Burgess <andrew.burgess@embecosm.com>]

* Tom de Vries <tdevries@suse.de> [2019-10-07 11:33:12 +0200]:

> On 04-10-19 00:56, Weimin Pan wrote:
> > +/* The routines that read and process fields/members of a C struct, union,
> > +   or enumeration, pass lists of data member fields in an instance of a
> > +   field_info structure. It is derived from dwarf2read.c.  */
> > +
> > +struct nextfield
> > +{
> > +  struct field field {};
> > +};
> > +
> > +struct field_info
> 
> Hi,
> 
> not only is field_info derived from dwarf2read.c, it uses the same name
> for the type.  This is a C++ One-Definition-Rule violation, which causes
> most of the test-suite to start failing for me.
> 
> What happens is that here:
> ...
>   if (die->child != NULL && ! die_is_declaration (die, cu))
>     {
>       struct field_info fi;
>       std::vector<struct symbol *> template_args;
> ...
> the constructor for field_info is called, but it calls the constructor
> for field_info defined in ctfread.c rather than dwarf2read.c.

Tom,

Thanks for tracking this down.  I had just run into the same issue.
I've pushed the patch below which I believe fixes this issue.

Weimin,

Hopefully you're happy with this fix, I guess if you'd rather see an
alternative solution then feel free to propose one.

Thanks,
Andrew

---

From b2caee6aaa78106d7ae3c46dda3a84a325e43a1d Mon Sep 17 00:00:00 2001
From: Andrew Burgess <andrew.burgess@embecosm.com>
Date: Mon, 7 Oct 2019 12:34:51 +0100
Subject: [PATCH] gdb: Rename structures within ctfread.c

Commit:

  commit 30d1f0184953478d14641c495261afd06ebfabac
  Date:   Mon Oct 7 00:46:52 2019 +0000

      gdb: CTF support

Introduces some structures with names that are already in use within
GBB, this violates C++'s one-definition rule.  Specifically the
structures 'nextfield' and 'field_info' are now defined in
dwarf2read.c and ctfread.c.

This commit renames the new structures (in ctfread.c), adding a 'ctf_'
prefix.  Maybe we should consider renaming the DWARF versions too in
the future to avoid accidental conflicts.

gdb/ChangeLog:

	* ctfread.c (struct nextfield): Renamed to ...
	(struct ctf_nextfield): ... this.
	(struct field_info): Renamed to ...
	(strut ctf_field_info): ... this.
	(attach_fields_to_type): Update for renamed structures.
	(ctf_add_member_cb): Likewise.
	(ctf_add_enum_member_cb): Likewise.
	(process_struct_members): Likewise.
	(process_enum_type): Likewise.
---
 gdb/ChangeLog | 12 ++++++++++++
 gdb/ctfread.c | 28 ++++++++++++++--------------
 2 files changed, 26 insertions(+), 14 deletions(-)

diff --git a/gdb/ctfread.c b/gdb/ctfread.c
index 3e3bd89d5f1..44ccff62ae3 100644
--- a/gdb/ctfread.c
+++ b/gdb/ctfread.c
@@ -98,17 +98,17 @@ typedef struct ctf_context
 
 /* The routines that read and process fields/members of a C struct, union,
    or enumeration, pass lists of data member fields in an instance of a
-   field_info structure. It is derived from dwarf2read.c.  */
+   ctf_field_info structure. It is derived from dwarf2read.c.  */
 
-struct nextfield
+struct ctf_nextfield
 {
   struct field field {};
 };
 
-struct field_info
+struct ctf_field_info
 {
   /* List of data member fields.  */
-  std::vector<struct nextfield> fields;
+  std::vector<struct ctf_nextfield> fields;
 
   /* Context.  */
   ctf_context_t *cur_context;
@@ -269,7 +269,7 @@ set_symbol_address (struct objfile *of, struct symbol *sym, const char *name)
 /* Create the vector of fields, and attach it to TYPE.  */
 
 static void
-attach_fields_to_type (struct field_info *fip, struct type *type)
+attach_fields_to_type (struct ctf_field_info *fip, struct type *type)
 {
   int nfields = fip->fields.size ();
 
@@ -284,7 +284,7 @@ attach_fields_to_type (struct field_info *fip, struct type *type)
   /* Copy the saved-up fields into the field vector.  */
   for (int i = 0; i < nfields; ++i)
     {
-      struct nextfield &field = fip->fields[i];
+      struct ctf_nextfield &field = fip->fields[i];
       TYPE_FIELD (type, i) = field.field;
     }
 }
@@ -314,7 +314,7 @@ ctf_init_float_type (struct objfile *objfile,
 
 /* Callback to add member NAME to a struct/union type. TID is the type
    of struct/union member, OFFSET is the offset of member in bits,
-   and ARG contains the field_info.  */
+   and ARG contains the ctf_field_info.  */
 
 static int
 ctf_add_member_cb (const char *name,
@@ -322,9 +322,9 @@ ctf_add_member_cb (const char *name,
 		   unsigned long offset,
 		   void *arg)
 {
-  struct field_info *fip = (struct field_info *) arg;
+  struct ctf_field_info *fip = (struct ctf_field_info *) arg;
   ctf_context_t *ccp = fip->cur_context;
-  struct nextfield new_field;
+  struct ctf_nextfield new_field;
   struct field *fp;
   struct type *t;
   uint32_t kind;
@@ -358,13 +358,13 @@ ctf_add_member_cb (const char *name,
 }
 
 /* Callback to add member NAME of EVAL to an enumeration type.
-   ARG contains the field_info.  */
+   ARG contains the ctf_field_info.  */
 
 static int
 ctf_add_enum_member_cb (const char *name, int enum_value, void *arg)
 {
-  struct field_info *fip = (struct field_info *) arg;
-  struct nextfield new_field;
+  struct ctf_field_info *fip = (struct ctf_field_info *) arg;
+  struct ctf_nextfield new_field;
   struct field *fp;
   ctf_context_t *ccp = fip->cur_context;
 
@@ -587,7 +587,7 @@ process_struct_members (ctf_context_t *ccp,
 			ctf_id_t tid,
 			struct type *type)
 {
-  struct field_info fi;
+  struct ctf_field_info fi;
 
   fi.cur_context = ccp;
   if (ctf_member_iter (ccp->fp, tid, ctf_add_member_cb, &fi) == CTF_ERR)
@@ -665,7 +665,7 @@ static void
 process_enum_type (ctf_context_t *ccp, ctf_id_t tid)
 {
   struct type *type;
-  struct field_info fi;
+  struct ctf_field_info fi;
 
   type = read_enum_type (ccp, tid);
 
-- 
2.14.5