[patch 1/2] Perform a namespace lookup at every block level

Sami Wagiaalla
2009-08-18T20:34:32Z

> cp_lookup_symbol_namespace did two things look in the current namespace
> as well as examine applicable imports. I realized that we didnt need to
> examine imports at each scope level. We can simply look at the import
> destination.
>
> This patch separates the two kinds of lookups (imports and scopes) and
> performs the import lookup at every block level.
>

Same as above, but I fixed a couple of issues with the previous patch.
The first issue is that even while we iterate over blocks the original
scope should be used. Secondly, the call to lookup_symbol_name space
in valops.c must also perform a per block search. The final issue is
recursive search which is discussed in part 2 of this patch.

----

2009-08-11 Sami Wagiaalla <swagiaal@redhat.com>

* dwarf2read.c (read_lexical_block_scope): Create blocks for scopes
which contain using directives even if they contain no declarations.
* symtab.c (lookup_symbol_aux): Pass lowest level
block to la_lookup_symbol_nonlocal.
* cp-namespace.c (cp_lookup_symbol_nonlocal): call
cp_lookup_symbol_namespace.
(cp_lookup_symbol_namespace): Perform an import lookup at every block
level.
(cp_lookup_symbol_imports): New function.
(cp_lookup_symbol_in_namespace): New function.

2009-08-11 Sami Wagiaalla <swagiaal@redhat.com>

* gdb.cp/namespace-using.exp: Add test for printing of namespaces
imported into file scope.
Marked test as xfail.
* gdb.cp/namespace-using.cc (marker5): New function.

diff --git a/gdb/cp-namespace.c b/gdb/cp-namespace.c
index d2d8f2e..a0ccd7f 100644
--- a/gdb/cp-namespace.c
+++ b/gdb/cp-namespace.c
@@ -42,6 +42,18 @@ static struct symbol *lookup_namespace_scope (const char *name,
const char *scope,
int scope_len);

+static struct symbol *cp_lookup_symbol_imports (const char *scope,
+ const char *name,
+ const char *linkage_name,
+ const struct block *block,
+ const domain_enum domain);
+
+static struct symbol *cp_lookup_symbol_in_namespace (const char *namespace,
+ const char *name,
+ const char *linkage_name,
+ const struct block *block,
+ const domain_enum domain);
+
static struct symbol *lookup_symbol_file (const char *name,
const char *linkage_name,
const struct block *block,
@@ -265,8 +277,41 @@ cp_lookup_symbol_nonlocal (const char *name,
const struct block *block,
const domain_enum domain)
{
- return lookup_namespace_scope (name, linkage_name, block, domain,
- block_scope (block), 0);
+ struct symbol *sym;
+ const char *scope = block_scope (block);
+
+ sym = lookup_namespace_scope (name, linkage_name, block, domain, scope, 0);
+ if ( sym != NULL)
+ return sym;
+
+ return cp_lookup_symbol_namespace(scope, name, linkage_name, block, domain);
+}
+
+/* Searches for NAME in the current namespace, and by applying relevant import
+ statements belonging to BLOCK and its parents. SCOPE is the namespace scope
+ of the context in which the search is being evaluated. */
+
+struct symbol*
+cp_lookup_symbol_namespace (const char *scope,
+ const char *name,
+ const char *linkage_name,
+ const struct block *block,
+ const domain_enum domain)
+{
+ struct symbol *sym;
+
+ /* Search for name in namespaces imported to this and parent blocks. */
+ while (block != NULL)
+ {
+ sym = cp_lookup_symbol_imports(scope,name, linkage_name, block, domain);
+
+ if (sym)
+ return sym;
+
+ block = BLOCK_SUPERBLOCK(block);
+ }
+
+ return NULL;
}

/* Lookup NAME at namespace scope (or, in C terms, in static and
@@ -320,25 +365,59 @@ lookup_namespace_scope (const char *name,
namespace = alloca (scope_len + 1);
strncpy (namespace, scope, scope_len);
namespace[scope_len] = '\0';
- return cp_lookup_symbol_namespace (namespace, name, linkage_name,
+ return cp_lookup_symbol_in_namespace (namespace, name, linkage_name,
block, domain);
}

-/* Look up NAME in the C++ namespace NAMESPACE, applying the using
- directives that are active in BLOCK. Other arguments are as in
+/* Look up NAME in the C++ namespace NAMESPACE. Other arguments are as in
cp_lookup_symbol_nonlocal. */

-struct symbol *
-cp_lookup_symbol_namespace (const char *namespace,
- const char *name,
- const char *linkage_name,
- const struct block *block,
- const domain_enum domain)
+static struct symbol *
+cp_lookup_symbol_in_namespace (const char *namespace,
+ const char *name,
+ const char *linkage_name,
+ const struct block *block,
+ const domain_enum domain)
+{
+
+ if (namespace[0] == '\0')
+ {
+ return lookup_symbol_file (name, linkage_name, block,
+ domain, 0);
+ }
+ else
+ {
+ char *concatenated_name
+ = alloca (strlen (namespace) + 2 + strlen (name) + 1);
+ strcpy (concatenated_name, namespace);
+ strcat (concatenated_name, "::");
+ strcat (concatenated_name, name);
+ return lookup_symbol_file (concatenated_name, linkage_name,
+ block, domain,
+ cp_is_anonymous (namespace));
+ }
+}
+
+/* Search for NAME by applying all import statements belonging
+ to BLOCK which are applicable in SCOPE. */
+
+static struct symbol *
+cp_lookup_symbol_imports (const char *scope,
+ const char *name,
+ const char *linkage_name,
+ const struct block *block,
+ const domain_enum domain)
{
const struct using_direct *current;
struct symbol *sym;

- /* First, go through the using directives. If any of them add new
+ /* First, try to find the symbol in the given namespace. */
+ sym = cp_lookup_symbol_in_namespace (scope, name, linkage_name, block,
+ domain);
+ if ( sym != NULL)
+ return sym;
+
+ /* Go through the using directives. If any of them add new
names to the namespace we're searching in, see if we can find a
match by applying them. */

@@ -346,9 +425,12 @@ cp_lookup_symbol_namespace (const char *namespace,
current != NULL;
current = current->next)
{
- if (strcmp (namespace, current->import_dest) == 0)
+
+ /* If the import destination is the current scope or one of its ancestors then
+ it is applicable. */
+ if (strncmp (scope, current->import_dest, strlen(current->import_dest)) == 0)
{
- sym = cp_lookup_symbol_namespace (current->import_src,
+ sym = cp_lookup_symbol_in_namespace (current->import_src,
name,
linkage_name,
block,
@@ -358,27 +440,7 @@ cp_lookup_symbol_namespace (const char *namespace,
}
}

- /* We didn't find anything by applying any of the using directives
- that are still applicable; so let's see if we've got a match
- using the current namespace. */
-
- if (namespace[0] == '\0')
- {
- return lookup_symbol_file (name, linkage_name, block,
- domain, 0);
- }
- else
- {
- char *concatenated_name
- = alloca (strlen (namespace) + 2 + strlen (name) + 1);
- strcpy (concatenated_name, namespace);
- strcat (concatenated_name, "::");
- strcat (concatenated_name, name);
- sym = lookup_symbol_file (concatenated_name, linkage_name,
- block, domain,
- cp_is_anonymous (namespace));
- return sym;
- }
+ return NULL;
}

/* Look up NAME in BLOCK's static block and in global blocks. If
@@ -461,7 +523,7 @@ cp_lookup_nested_type (struct type *parent_type,
lookup_symbol_namespace works when looking them up. */

const char *parent_name = TYPE_TAG_NAME (parent_type);
- struct symbol *sym = cp_lookup_symbol_namespace (parent_name,
+ struct symbol *sym = cp_lookup_symbol_in_namespace (parent_name,
nested_name,
NULL,
block,
diff --git a/gdb/dwarf2read.c b/gdb/dwarf2read.c
index 445bab8..f18d804 100644
--- a/gdb/dwarf2read.c
+++ b/gdb/dwarf2read.c
@@ -3922,7 +3922,7 @@ read_lexical_block_scope (struct die_info *die, struct dwarf2_cu *cu)
}
new = pop_context ();

- if (local_symbols != NULL)
+ if (local_symbols != NULL || using_directives != NULL)
{
struct block *block
= finish_block (0, &local_symbols, new->old_blocks, new->start_addr,
diff --git a/gdb/symtab.c b/gdb/symtab.c
index c88156a..cebbb4b 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -1304,13 +1304,14 @@ lookup_symbol_aux (const char *name, const char *linkage_name,
&& block != NULL)
{
struct symbol *sym = NULL;
+ const struct block *function_block = block;
/* 'this' is only defined in the function's block, so find the
enclosing function block. */
- for (; block && !BLOCK_FUNCTION (block);
- block = BLOCK_SUPERBLOCK (block));
+ for (; function_block && !BLOCK_FUNCTION (function_block);
+ function_block = BLOCK_SUPERBLOCK (function_block));

- if (block && !dict_empty (BLOCK_DICT (block)))
- sym = lookup_block_symbol (block, langdef->la_name_of_this,
+ if (function_block && !dict_empty (BLOCK_DICT (function_block)))
+ sym = lookup_block_symbol (function_block, langdef->la_name_of_this,
NULL, VAR_DOMAIN);
if (sym)
{
@@ -1334,11 +1335,14 @@ lookup_symbol_aux (const char *name, const char *linkage_name,
return NULL;
}
}
- }

- /* Now do whatever is appropriate for LANGUAGE to look
- up static and global variables. */
+ /* C++ language specific lookup requires the lowest block level. */
+ if (language != language_cplus)
+ block = function_block;
+
+ }

+ /* Now do whatever is appropriate for LANGUAGE specific lookup. */
sym = langdef->la_lookup_symbol_nonlocal (name, linkage_name, block, domain);
if (sym != NULL)
return sym;
diff --git a/gdb/testsuite/gdb.cp/namespace-using.cc b/gdb/testsuite/gdb.cp/namespace-using.cc
index 4786fd5..091b4cc 100644
--- a/gdb/testsuite/gdb.cp/namespace-using.cc
+++ b/gdb/testsuite/gdb.cp/namespace-using.cc
@@ -1,3 +1,16 @@
+namespace C
+{
+ int cc = 3;
+}
+
+using namespace C;
+int marker5()
+{
+ cc;
+ return 0;
+}
+
+
namespace A
{
int _a = 1;
@@ -6,7 +19,7 @@ namespace A

int marker4(){
using A::x;
- return 0;
+ return marker5();
}

int marker3(){
diff --git a/gdb/testsuite/gdb.cp/namespace-using.exp b/gdb/testsuite/gdb.cp/namespace-using.exp
index f24973f..bd1016b 100644
--- a/gdb/testsuite/gdb.cp/namespace-using.exp
+++ b/gdb/testsuite/gdb.cp/namespace-using.exp
@@ -28,6 +28,11 @@ if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {deb
return -1
}

+if [get_compiler_info ${binfile}] {
+ return -1;
+}
+
+
# Get things started.

gdb_exit
@@ -73,7 +78,13 @@ gdb_test "print B::a" "= 1"
gdb_breakpoint "marker3"
gdb_continue_to_breakpoint "marker3"

-gdb_test "print _a" "No symbol \"_a\" in current context." "Print a without import"
+# gcc-4-3 puts import statements for aliases in
+# the global scope instead of the corresponding
+# function scope. These wrong import statements throw
+# this test off. This is fixed in gcc-4-4.
+if [test_compiler_info gcc-4-3-*] then { setup_xfail *-*-* }
+
+gdb_test "print _a" "No symbol \"_a\" in current context." "Print _a without import"

############################################
# Test printing of individually imported elements
@@ -85,3 +96,14 @@ if ![runto marker4] then {
}

gdb_test "print x" "= 2"
+
+############################################
+# test printing of namespace imported into
+# file scope.
+
+if ![runto marker5] then {
+ perror "couldn't run to marker5"
+ continue
+}
+
+gdb_test "print cc" "= 3"