[PATCH 3/7] jit: c++-ify gdb_symtab

Simon Marchi
2019-12-13T06:03:33Z

This patch makes the gdb_symtab bit more c++y. It changes the fields to
use automatic memory management, in the form of std::string and
gdb::unique_xmalloc_ptr, and adds a constructor and a destructor.

gdb/ChangeLog:

* jit.c (struct gdb_symtab): Add constructor, destructor,
initialize fields.
<linetable>: Change type to unique_xmalloc_ptr.
<file_name>: Change type to std::string.
(jit_symtab_open_impl): Allocate gdb_symtab with new.
(jit_symtab_line_mapping_add_impl): Adjust.
(finalize_symtab): Call delete on stab.
---
gdb/jit.c | 63 +++++++++++++++++++++++++++++--------------------------
1 file changed, 33 insertions(+), 30 deletions(-)

diff --git a/gdb/jit.c b/gdb/jit.c
index 672a74044af3..eace83e583d3 100644
--- a/gdb/jit.c
+++ b/gdb/jit.c
@@ -450,18 +450,37 @@ struct gdb_block

struct gdb_symtab
{
+ gdb_symtab (const char *file_name)
+ : file_name (file_name != nullptr ? file_name : "")
+ {}
+
+ ~gdb_symtab ()
+ {
+ gdb_block *gdb_block_iter, *gdb_block_iter_tmp;
+
+ for ((gdb_block_iter = this->blocks,
+ gdb_block_iter_tmp = gdb_block_iter->next);
+ gdb_block_iter;
+ gdb_block_iter = gdb_block_iter_tmp)
+ {
+ gdb_block_iter_tmp = gdb_block_iter->next;
+ xfree ((void *) gdb_block_iter->name);
+ xfree (gdb_block_iter);
+ }
+ }
+
/* The list of blocks in this symtab. These will eventually be
converted to real blocks. */
- struct gdb_block *blocks;
+ struct gdb_block *blocks = nullptr;

/* The number of blocks inserted. */
- int nblocks;
+ int nblocks = 0;

/* A mapping between line numbers to PC. */
- struct linetable *linetable;
+ gdb::unique_xmalloc_ptr<struct linetable> linetable;

/* The source file for this symtab. */
- const char *file_name;
+ std::string file_name;
};

/* Proxy object for building an object. */
@@ -511,14 +530,11 @@ jit_symtab_open_impl (struct gdb_symbol_callbacks *cb,
struct gdb_object *object,
const char *file_name)
{
- struct gdb_symtab *ret;
-
/* CB stays unused. See comment in jit_object_open_impl. */

- ret = XCNEW (struct gdb_symtab);
- ret->file_name = file_name ? xstrdup (file_name) : xstrdup ("");
- object->symtabs.push_back (ret);
- return ret;
+ gdb_symtab *symtab = new gdb_symtab (file_name);
+ object->symtabs.push_back (symtab);
+ return symtab;
}

/* Returns true if the block corresponding to old should be placed
@@ -603,7 +619,7 @@ jit_symtab_line_mapping_add_impl (struct gdb_symbol_callbacks *cb,

alloc_len = sizeof (struct linetable)
+ (nlines - 1) * sizeof (struct linetable_entry);
- stab->linetable = (struct linetable *) xmalloc (alloc_len);
+ stab->linetable.reset (XNEWVAR (struct linetable, alloc_len));
stab->linetable->nitems = nlines;
for (i = 0; i < nlines; i++)
{
@@ -630,7 +646,7 @@ static void
finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
{
struct compunit_symtab *cust;
- struct gdb_block *gdb_block_iter, *gdb_block_iter_tmp;
+ struct gdb_block *gdb_block_iter;
struct block *block_iter;
int actual_nblocks, i;
size_t blockvector_size;
@@ -639,8 +655,8 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)

actual_nblocks = FIRST_LOCAL_BLOCK + stab->nblocks;

- cust = allocate_compunit_symtab (objfile, stab->file_name);
- allocate_symtab (cust, stab->file_name);
+ cust = allocate_compunit_symtab (objfile, stab->file_name.c_str ());
+ allocate_symtab (cust, stab->file_name.c_str ());
add_compunit_symtab_to_objfile (cust);

/* JIT compilers compile in memory. */
@@ -654,8 +670,8 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
+ sizeof (struct linetable));
SYMTAB_LINETABLE (COMPUNIT_FILETABS (cust))
= (struct linetable *) obstack_alloc (&objfile->objfile_obstack, size);
- memcpy (SYMTAB_LINETABLE (COMPUNIT_FILETABS (cust)), stab->linetable,
- size);
+ memcpy (SYMTAB_LINETABLE (COMPUNIT_FILETABS (cust)),
+ stab->linetable.get (), size);
}

blockvector_size = (sizeof (struct blockvector)
@@ -756,20 +772,7 @@ finalize_symtab (struct gdb_symtab *stab, struct objfile *objfile)
}
}

- /* Free memory. */
- gdb_block_iter = stab->blocks;
-
- for (gdb_block_iter = stab->blocks, gdb_block_iter_tmp = gdb_block_iter->next;
- gdb_block_iter;
- gdb_block_iter = gdb_block_iter_tmp)
- {
- gdb_block_iter_tmp = gdb_block_iter->next;
- xfree ((void *) gdb_block_iter->name);
- xfree (gdb_block_iter);
- }
- xfree (stab->linetable);
- xfree ((char *) stab->file_name);
- xfree (stab);
+ delete stab;
}

/* Called when closing a gdb_objfile. Converts OBJ to a proper
--
2.24.1