[PATCH v2 28/42] Remove dwarf2_per_cu_data::objfile ()

Simon Marchi
2020-05-12T21:15:19Z

Since dwarf2_per_cu_data objects are going to become
objfile-independent, the backlink from dwarf2_per_cu_data to one
particular objfile must be removed. Instead, users of
dwarf2_per_cu_data that need an objfile must know from somewhere else in
the context of which objfile they are using this CU.

This also helps remove a dwarf2_per_cu_data::dwarf2_per_objfile
reference (from where the objfile was obtained).

Note that the dwarf2_per_cu_data::objfile method has a special case to
make sure to return the main objfile, if the objfile associated to the
dwarf2_per_cu_data is a separate debug objfile. I don't really know if
this is necessary: I ignored that, and didn't see any regression when
testing with the various Dejagnu boards with separate debug info, so I
presume it wasn't needed. If it turns out this was needed, then we can
have a helper method on the objfile type for that.

gdb/ChangeLog:

* dwarf2/read.h (struct dwarf2_per_cu_data) <objfile>: Remove.
* dwarf2/read.c (dwarf2_compute_name): Pass per_objfile down.
(read_call_site_scope): Assign per_objfile.
(dwarf2_per_cu_data::objfile): Remove.
* gdbtypes.h (struct call_site) <per_objfile>: New member.
* dwarf2/loc.h (dwarf2_evaluate_loc_desc): Add
dwarf2_per_objfile parameter.
* dwarf2/loc.c (dwarf2_evaluate_loc_desc_full): Add
dwarf2_per_objfile parameter.
(dwarf_expr_reg_to_entry_parameter): Add output
dwarf2_per_objfile parameter.
(locexpr_get_frame_base): Update.
(class dwarf_evaluate_loc_desc) <get_tls_address>: Update.
<push_dwarf_reg_entry_value>: Update.
<call_site_to_target_addr>: Update.
(dwarf_entry_parameter_to_value): Add dwarf2_per_objfile
parameter.
(value_of_dwarf_reg_entry): Update.
(rw_pieced_value): Update.
(indirect_synthetic_pointer): Update.
(dwarf2_evaluate_property): Update.
(dwarf2_loc_desc_get_symbol_read_needs): Add dwarf2_per_objfile
parameter.
(locexpr_read_variable): Update.
(locexpr_get_symbol_read_needs): Update.
(loclist_read_variable): Update.
---
gdb/dwarf2/loc.c | 94 ++++++++++++++++++++++++++---------------------
gdb/dwarf2/loc.h | 3 +-
gdb/dwarf2/read.c | 19 ++--------
gdb/dwarf2/read.h | 5 ---
gdb/gdbtypes.h | 8 +++-
5 files changed, 65 insertions(+), 64 deletions(-)

diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
index c1ccbda8235..a4b7edf7bff 100644
--- a/gdb/dwarf2/loc.c
+++ b/gdb/dwarf2/loc.c
@@ -47,19 +47,17 @@
#include "gdbsupport/underlying.h"
#include "gdbsupport/byte-vector.h"

-static struct value *dwarf2_evaluate_loc_desc_full (struct type *type,
- struct frame_info *frame,
- const gdb_byte *data,
- size_t size,
- struct dwarf2_per_cu_data *per_cu,
- struct type *subobj_type,
- LONGEST subobj_byte_offset);
+static struct value *dwarf2_evaluate_loc_desc_full
+ (struct type *type, struct frame_info *frame, const gdb_byte *data,
+ size_t size, dwarf2_per_cu_data *per_cu, dwarf2_per_objfile *per_objfile,
+ struct type *subobj_type, LONGEST subobj_byte_offset);

static struct call_site_parameter *dwarf_expr_reg_to_entry_parameter
(struct frame_info *frame,
enum call_site_parameter_kind kind,
union call_site_parameter_u kind_u,
- struct dwarf2_per_cu_data **per_cu_return);
+ dwarf2_per_cu_data **per_cu_return,
+ dwarf2_per_objfile **per_objfile_return);

static struct value *indirect_synthetic_pointer
(sect_offset die, LONGEST byte_offset,
@@ -476,7 +474,7 @@ locexpr_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
(framefunc, get_frame_pc (frame), &start, &length);
result = dwarf2_evaluate_loc_desc (type, frame, start, length,
- dlbaton->per_cu);
+ dlbaton->per_cu, dlbaton->per_objfile);

/* The DW_AT_frame_base attribute contains a location description which
computes the base address itself. However, the call to
@@ -533,7 +531,7 @@ loclist_get_frame_base (struct symbol *framefunc, struct frame_info *frame)
SYMBOL_BLOCK_OPS (framefunc)->find_frame_base_location
(framefunc, get_frame_pc (frame), &start, &length);
result = dwarf2_evaluate_loc_desc (type, frame, start, length,
- dlbaton->per_cu);
+ dlbaton->per_cu, dlbaton->per_objfile);

/* The DW_AT_frame_base attribute contains a location description which
computes the base address itself. However, the call to
@@ -654,9 +652,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
current thread's thread-local storage with offset OFFSET. */
CORE_ADDR get_tls_address (CORE_ADDR offset) override
{
- struct objfile *objfile = per_cu->objfile ();
-
- return target_translate_tls_address (objfile, offset);
+ return target_translate_tls_address (per_objfile->objfile, offset);
}

/* Helper interface of per_cu_dwarf_call for
@@ -716,7 +712,8 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
int deref_size) override
{
struct frame_info *caller_frame;
- struct dwarf2_per_cu_data *caller_per_cu;
+ dwarf2_per_cu_data *caller_per_cu;
+ dwarf2_per_objfile *caller_per_objfile;
struct call_site_parameter *parameter;
const gdb_byte *data_src;
size_t size;
@@ -724,10 +721,13 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
caller_frame = get_prev_frame (frame);

parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
- &caller_per_cu);
+ &caller_per_cu,
+ &caller_per_objfile);
data_src = deref_size == -1 ? parameter->value : parameter->data_value;
size = deref_size == -1 ? parameter->value_size : parameter->data_value_size;

+ gdb_assert (this->per_objfile == caller_per_objfile);
+
/* DEREF_SIZE size is not verified here. */
if (data_src == NULL)
throw_error (NO_ENTRY_VALUE_ERROR,
@@ -741,7 +741,7 @@ class dwarf_evaluate_loc_desc : public dwarf_expr_context
(CORE_ADDR) 0);

scoped_restore save_arch = make_scoped_restore (&this->gdbarch);
- this->gdbarch = per_cu->objfile ()->arch ();
+ this->gdbarch = this->per_objfile->objfile->arch ();
scoped_restore save_addr_size = make_scoped_restore (&this->addr_size);
this->addr_size = per_cu->addr_size ();

@@ -869,7 +869,8 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
caller_core_addr_type = builtin_type (caller_arch)->builtin_func_ptr;
val = dwarf2_evaluate_loc_desc (caller_core_addr_type, caller_frame,
dwarf_block->data, dwarf_block->size,
- dwarf_block->per_cu);
+ dwarf_block->per_cu,
+ dwarf_block->per_objfile);
/* DW_AT_call_target is a DWARF expression, not a DWARF location. */
if (VALUE_LVAL (val) == lval_memory)
return value_address (val);
@@ -1290,7 +1291,8 @@ static struct call_site_parameter *
dwarf_expr_reg_to_entry_parameter (struct frame_info *frame,
enum call_site_parameter_kind kind,
union call_site_parameter_u kind_u,
- struct dwarf2_per_cu_data **per_cu_return)
+ dwarf2_per_cu_data **per_cu_return,
+ dwarf2_per_objfile **per_objfile_return)
{
CORE_ADDR func_addr, caller_pc;
struct gdbarch *gdbarch;
@@ -1381,6 +1383,7 @@ dwarf_expr_reg_to_entry_parameter (struct frame_info *frame,
}

*per_cu_return = call_site->per_cu;
+ *per_objfile_return = call_site->per_objfile;
return parameter;
}

@@ -1398,7 +1401,8 @@ static struct value *
dwarf_entry_parameter_to_value (struct call_site_parameter *parameter,
CORE_ADDR deref_size, struct type *type,
struct frame_info *caller_frame,
- struct dwarf2_per_cu_data *per_cu)
+ dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile)
{
const gdb_byte *data_src;
gdb_byte *data;
@@ -1419,7 +1423,8 @@ dwarf_entry_parameter_to_value (struct call_site_parameter *parameter,
memcpy (data, data_src, size);
data[size] = DW_OP_stack_value;

- return dwarf2_evaluate_loc_desc (type, caller_frame, data, size + 1, per_cu);
+ return dwarf2_evaluate_loc_desc (type, caller_frame, data, size + 1, per_cu,
+ per_objfile);
}

/* VALUE must be of type lval_computed with entry_data_value_funcs. Perform
@@ -1493,14 +1498,17 @@ value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
struct frame_info *caller_frame = get_prev_frame (frame);
struct value *outer_val, *target_val, *val;
struct call_site_parameter *parameter;
- struct dwarf2_per_cu_data *caller_per_cu;
+ dwarf2_per_cu_data *caller_per_cu;
+ dwarf2_per_objfile *caller_per_objfile;

parameter = dwarf_expr_reg_to_entry_parameter (frame, kind, kind_u,
- &caller_per_cu);
+ &caller_per_cu,
+ &caller_per_objfile);

outer_val = dwarf_entry_parameter_to_value (parameter, -1 /* deref_size */,
type, caller_frame,
- caller_per_cu);
+ caller_per_cu,
+ caller_per_objfile);

/* Check if DW_AT_call_data_value cannot be used. If it should be
used and it is not available do not fall back to OUTER_VAL - dereferencing
@@ -1514,7 +1522,8 @@ value_of_dwarf_reg_entry (struct type *type, struct frame_info *frame,
target_val = dwarf_entry_parameter_to_value (parameter,
TYPE_LENGTH (target_type),
target_type, caller_frame,
- caller_per_cu);
+ caller_per_cu,
+ caller_per_objfile);

val = allocate_computed_value (type, &entry_data_value_funcs,
release_value (target_val).release ());
@@ -1831,8 +1840,7 @@ rw_pieced_value (struct value *v, struct value *from)
break;
}

- struct objfile *objfile = c->per_cu->objfile ();
- struct gdbarch *objfile_gdbarch = objfile->arch ();
+ gdbarch *objfile_gdbarch = c->per_objfile->objfile->arch ();
ULONGEST stack_value_size_bits
= 8 * TYPE_LENGTH (value_type (p->v.value));

@@ -2023,6 +2031,7 @@ indirect_synthetic_pointer (sect_offset die, LONGEST byte_offset,
if (baton.data != NULL)
return dwarf2_evaluate_loc_desc_full (orig_type, frame, baton.data,
baton.size, baton.per_cu,
+ baton.per_objfile,
TYPE_TARGET_TYPE (type),
byte_offset);
else
@@ -2187,12 +2196,12 @@ static const struct lval_funcs pieced_value_funcs = {
static struct value *
dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
const gdb_byte *data, size_t size,
- struct dwarf2_per_cu_data *per_cu,
+ dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile,
struct type *subobj_type,
LONGEST subobj_byte_offset)
{
struct value *retval;
- struct objfile *objfile = per_cu->objfile ();

if (subobj_type == NULL)
{
@@ -2205,7 +2214,6 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
if (size == 0)
return allocate_optimized_out_value (subobj_type);

- dwarf2_per_objfile *per_objfile = get_dwarf2_per_objfile (objfile);
dwarf_evaluate_loc_desc ctx (per_objfile);
ctx.frame = frame;
ctx.per_cu = per_cu;
@@ -2213,7 +2221,7 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,

scoped_value_mark free_values;

- ctx.gdbarch = objfile->arch ();
+ ctx.gdbarch = per_objfile->objfile->arch ();
ctx.addr_size = per_cu->addr_size ();
ctx.ref_addr_size = per_cu->ref_addr_size ();

@@ -2336,7 +2344,7 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
size_t n = TYPE_LENGTH (value_type (value));
size_t len = TYPE_LENGTH (subobj_type);
size_t max = TYPE_LENGTH (type);
- struct gdbarch *objfile_gdbarch = objfile->arch ();
+ gdbarch *objfile_gdbarch = per_objfile->objfile->arch ();

if (subobj_byte_offset + len > max)
invalid_synthetic_pointer ();
@@ -2399,10 +2407,11 @@ dwarf2_evaluate_loc_desc_full (struct type *type, struct frame_info *frame,
struct value *
dwarf2_evaluate_loc_desc (struct type *type, struct frame_info *frame,
const gdb_byte *data, size_t size,
- struct dwarf2_per_cu_data *per_cu)
+ dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile)
{
return dwarf2_evaluate_loc_desc_full (type, frame, data, size, per_cu,
- NULL, 0);
+ per_objfile, NULL, 0);
}

/* A specialization of dwarf_evaluate_loc_desc that is used by
@@ -2603,7 +2612,8 @@ dwarf2_evaluate_property (const struct dynamic_prop *prop,
if (data != NULL)
{
val = dwarf2_evaluate_loc_desc (baton->property_type, frame, data,
- size, baton->loclist.per_cu);
+ size, baton->loclist.per_cu,
+ baton->loclist.per_objfile);
if (!value_optimized_out (val))
{
*value = value_as_address (val);
@@ -2806,18 +2816,18 @@ class symbol_needs_eval_context : public dwarf_expr_context

static enum symbol_needs_kind
dwarf2_loc_desc_get_symbol_read_needs (const gdb_byte *data, size_t size,
- struct dwarf2_per_cu_data *per_cu)
+ dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile)
{
int in_reg;
- struct objfile *objfile = per_cu->objfile ();

scoped_value_mark free_values;

- symbol_needs_eval_context ctx (get_dwarf2_per_objfile (objfile));
+ symbol_needs_eval_context ctx (per_objfile);

ctx.needs = SYMBOL_NEEDS_NONE;
ctx.per_cu = per_cu;
- ctx.gdbarch = objfile->arch ();
+ ctx.gdbarch = per_objfile->objfile->arch ();
ctx.addr_size = per_cu->addr_size ();
ctx.ref_addr_size = per_cu->ref_addr_size ();

@@ -3641,7 +3651,8 @@ locexpr_read_variable (struct symbol *symbol, struct frame_info *frame)
struct value *val;

val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, dlbaton->data,
- dlbaton->size, dlbaton->per_cu);
+ dlbaton->size, dlbaton->per_cu,
+ dlbaton->per_objfile);

return val;
}
@@ -3670,7 +3681,8 @@ locexpr_get_symbol_read_needs (struct symbol *symbol)
= (struct dwarf2_locexpr_baton *) SYMBOL_LOCATION_BATON (symbol);

return dwarf2_loc_desc_get_symbol_read_needs (dlbaton->data, dlbaton->size,
- dlbaton->per_cu);
+ dlbaton->per_cu,
+ dlbaton->per_objfile);
}

/* Return true if DATA points to the end of a piece. END is one past
@@ -4460,7 +4472,7 @@ loclist_read_variable (struct symbol *symbol, struct frame_info *frame)

data = dwarf2_find_location_expression (dlbaton, &size, pc);
val = dwarf2_evaluate_loc_desc (SYMBOL_TYPE (symbol), frame, data, size,
- dlbaton->per_cu);
+ dlbaton->per_cu, dlbaton->per_objfile);

return val;
}
diff --git a/gdb/dwarf2/loc.h b/gdb/dwarf2/loc.h
index 51f242ec431..907455b72c1 100644
--- a/gdb/dwarf2/loc.h
+++ b/gdb/dwarf2/loc.h
@@ -61,7 +61,8 @@ struct value *dwarf2_evaluate_loc_desc (struct type *type,
struct frame_info *frame,
const gdb_byte *data,
size_t size,
- struct dwarf2_per_cu_data *per_cu);
+ dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile);

/* A chain of addresses that might be needed to resolve a dynamic
property. */
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index d221d0148c0..63449cf2c6f 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -10316,7 +10316,8 @@ dwarf2_compute_name (const char *name,
v = dwarf2_evaluate_loc_desc (type, NULL,
baton->data,
baton->size,
- baton->per_cu);
+ baton->per_cu,
+ baton->per_objfile);
else if (bytes != NULL)
{
v = allocate_value (type);
@@ -13460,6 +13461,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
sect_offset_str (die->sect_off), objfile_name (objfile));

call_site->per_cu = cu->per_cu;
+ call_site->per_objfile = per_objfile;

for (child_die = die->child;
child_die && child_die->tag;
@@ -23277,21 +23279,6 @@ dwarf2_symbol_mark_computed (const struct attribute *attr, struct symbol *sym,
}
}

-/* See read.h. */
-
-struct objfile *
-dwarf2_per_cu_data::objfile () const
-{
- struct objfile *objfile = dwarf2_per_objfile->objfile;
-
- /* Return the master objfile, so that we can report and look up the
- correct file containing this variable. */
- if (objfile->separate_debug_objfile_backlink)
- objfile = objfile->separate_debug_objfile_backlink;
-
- return objfile;
-}
-
/* Return comp_unit_head for PER_CU, either already available in PER_CU->CU
(CU_HEADERP is unused in such case) or prepare a temporary copy at
CU_HEADERP first. */
diff --git a/gdb/dwarf2/read.h b/gdb/dwarf2/read.h
index c6d236b4778..dda5ed71c4d 100644
--- a/gdb/dwarf2/read.h
+++ b/gdb/dwarf2/read.h
@@ -491,11 +491,6 @@ struct dwarf2_per_cu_data
imported_symtabs = nullptr;
}

- /* Return the OBJFILE associated with this compilation unit. If
- this compilation unit came from a separate debuginfo file, then
- the master objfile is returned. */
- struct objfile *objfile () const;
-
/* Return the address size given in the compilation unit header for
this CU. */
int addr_size () const;
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 7514bd27f7c..c8338f38495 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -58,6 +58,8 @@ struct field;
struct block;
struct value_print_options;
struct language_defn;
+struct dwarf2_per_cu_data;
+struct dwarf2_per_objfile;

/* These declarations are DWARF-specific as some of the gdbtypes.h data types
are already DWARF-specific. */
@@ -1333,7 +1335,11 @@ struct call_site
/* * CU of the function where the call is located. It gets used
for DWARF blocks execution in the parameter array below. */

- struct dwarf2_per_cu_data *per_cu;
+ dwarf2_per_cu_data *per_cu;
+
+ /* objfile of the function where the call is located. */
+
+ dwarf2_per_objfile *per_objfile;

/* * Describe DW_TAG_call_site's DW_TAG_formal_parameter. */

--
2.26.2