Allow DWARF expression to push the initial address

Some DWARF expressions must be evaluated by first pushing the object
address onto the evaluation stack.  This patch adds this ability.
This functionality is not used yet, but it will be used in a later
patch.  This is split out for easier review and also because it
improved the patch series ordering.

gdb/ChangeLog
2020-04-24  Tom Tromey  <tromey@adacore.com>

	* dwarf2/loc.c (dwarf2_locexpr_baton_eval): Add
	"push_initial_value" parameter.
	(dwarf2_evaluate_property): Likewise.
	* dwarf2/loc.h (dwarf2_evaluate_property): Update.
This commit is contained in:
Tom Tromey 2020-04-24 13:40:31 -06:00
parent ef83a141a2
commit 61122aa9ed
3 changed files with 24 additions and 6 deletions

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@ -1,3 +1,10 @@
2020-04-24 Tom Tromey <tromey@adacore.com>
* dwarf2/loc.c (dwarf2_locexpr_baton_eval): Add
"push_initial_value" parameter.
(dwarf2_evaluate_property): Likewise.
* dwarf2/loc.h (dwarf2_evaluate_property): Update.
2020-04-24 Tom Tromey <tromey@adacore.com>
* gdbtypes.c (is_dynamic_type_internal): Check for variant parts.

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@ -2388,13 +2388,16 @@ dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
that the dwarf expression only produces a single CORE_ADDR. FRAME is the
frame in which the expression is evaluated. ADDR is a context (location of
a variable) and might be needed to evaluate the location expression.
Returns 1 on success, 0 otherwise. */
PUSH_INITIAL_VALUE is true if ADDR should be pushed on the stack
before evaluating the expression; this is required by certain
forms of DWARF expression. Returns 1 on success, 0 otherwise. */
static int
dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
struct frame_info *frame,
CORE_ADDR addr,
CORE_ADDR *valp)
CORE_ADDR *valp,
bool push_initial_value)
{
struct objfile *objfile;
@ -2414,6 +2417,9 @@ dwarf2_locexpr_baton_eval (const struct dwarf2_locexpr_baton *dlbaton,
ctx.ref_addr_size = dlbaton->per_cu->ref_addr_size ();
ctx.offset = dlbaton->per_cu->text_offset ();
if (push_initial_value)
ctx.push_address (addr, false);
try
{
ctx.eval (dlbaton->data, dlbaton->size);
@ -2462,7 +2468,8 @@ bool
dwarf2_evaluate_property (const struct dynamic_prop *prop,
struct frame_info *frame,
const struct property_addr_info *addr_stack,
CORE_ADDR *value)
CORE_ADDR *value,
bool push_initial_value)
{
if (prop == NULL)
return false;
@ -2480,7 +2487,7 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
if (dwarf2_locexpr_baton_eval (&baton->locexpr, frame,
addr_stack ? addr_stack->addr : 0,
value))
value, push_initial_value))
{
if (baton->locexpr.is_reference)
{

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@ -92,12 +92,16 @@ struct property_addr_info
be NULL.
Returns true if PROP could be converted and the static value is passed
back into VALUE, otherwise returns false. */
back into VALUE, otherwise returns false.
If PUSH_INITIAL_VALUE is true, then the top value of ADDR_STACK
will be pushed before evaluating a location expression. */
bool dwarf2_evaluate_property (const struct dynamic_prop *prop,
struct frame_info *frame,
const struct property_addr_info *addr_stack,
CORE_ADDR *value);
CORE_ADDR *value,
bool push_initial_value = false);
/* A helper for the compiler interface that compiles a single dynamic
property to C code.