Re: [PATCH 3/4] [gdb/symtab] Add call_site::pc ()

Tom de Vries via Gdb-patches
2021-10-04T16:45:29Z

[-- Attachment #1: Type: text/plain, Size: 5677 bytes --]

On 10/1/21 8:10 PM, Simon Marchi wrote:
> On 2021-10-01 8:33 a.m., Tom de Vries via Gdb-patches wrote:
>> From: Simon Marchi <simon.marchi@polymtl.ca>
>>
>> Add member function call_site::pc () and update all uses.
>>
>> Tested on x86_64-linux.
>>
>> Co-Authored-By: Tom de Vries <tdevries@suse.de>
>> ---
>> gdb/dwarf2/frame-tailcall.c | 4 ++--
>> gdb/dwarf2/loc.c | 18 +++++++++---------
>> gdb/dwarf2/read.c | 2 +-
>> gdb/gdbtypes.c | 9 +++++++++
>> gdb/gdbtypes.h | 6 +++++-
>> 5 files changed, 26 insertions(+), 13 deletions(-)
>>
>> diff --git a/gdb/dwarf2/frame-tailcall.c b/gdb/dwarf2/frame-tailcall.c
>> index f112b4ecca4..9fe498b0924 100644
>> --- a/gdb/dwarf2/frame-tailcall.c
>> +++ b/gdb/dwarf2/frame-tailcall.c
>> @@ -240,14 +240,14 @@ pretend_pc (struct frame_info *this_frame, struct tailcall_cache *cache)
>> gdb_assert (next_levels >= 0);
>>
>> if (next_levels < chain->callees)
>> - return chain->call_site[chain->length - next_levels - 1]->pc;
>> + return chain->call_site[chain->length - next_levels - 1]->pc ();
>> next_levels -= chain->callees;
>>
>> /* Otherwise CHAIN->CALLEES are already covered by CHAIN->CALLERS. */
>> if (chain->callees != chain->length)
>> {
>> if (next_levels < chain->callers)
>> - return chain->call_site[chain->callers - next_levels - 1]->pc;
>> + return chain->call_site[chain->callers - next_levels - 1]->pc ();
>> next_levels -= chain->callers;
>> }
>>
>> diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
>> index 2322a01f396..27a1c97682a 100644
>> --- a/gdb/dwarf2/loc.c
>> +++ b/gdb/dwarf2/loc.c
>> @@ -654,10 +654,10 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
>> {
>> struct bound_minimal_symbol msym;
>>
>> - msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
>> + msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
>> throw_error (NO_ENTRY_VALUE_ERROR,
>> _("DW_AT_call_target is not specified at %s in %s"),
>> - paddress (call_site_gdbarch, call_site->pc),
>> + paddress (call_site_gdbarch, call_site->pc ()),
>> (msym.minsym == NULL ? "???"
>> : msym.minsym->print_name ()));
>>
>> @@ -666,12 +666,12 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
>> {
>> struct bound_minimal_symbol msym;
>>
>> - msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
>> + msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
>> throw_error (NO_ENTRY_VALUE_ERROR,
>> _("DW_AT_call_target DWARF block resolving "
>> "requires known frame which is currently not "
>> "available at %s in %s"),
>> - paddress (call_site_gdbarch, call_site->pc),
>> + paddress (call_site_gdbarch, call_site->pc ()),
>> (msym.minsym == NULL ? "???"
>> : msym.minsym->print_name ()));
>>
>> @@ -700,11 +700,11 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
>> msym = lookup_minimal_symbol (physname, NULL, NULL);
>> if (msym.minsym == NULL)
>> {
>> - msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
>> + msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
>> throw_error (NO_ENTRY_VALUE_ERROR,
>> _("Cannot find function \"%s\" for a call site target "
>> "at %s in %s"),
>> - physname, paddress (call_site_gdbarch, call_site->pc),
>> + physname, paddress (call_site_gdbarch, call_site->pc ()),
>> (msym.minsym == NULL ? "???"
>> : msym.minsym->print_name ()));
>>
>> @@ -810,7 +810,7 @@ func_verify_no_selftailcall (struct gdbarch *gdbarch, CORE_ADDR verify_addr)
>> static void
>> tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site)
>> {
>> - CORE_ADDR addr = call_site->pc;
>> + CORE_ADDR addr = call_site->pc ();
>> struct bound_minimal_symbol msym = lookup_minimal_symbol_by_pc (addr - 1);
>>
>> fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr),
>> @@ -986,7 +986,7 @@ call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
>>
>> if (target_call_site)
>> {
>> - if (addr_hash.insert (target_call_site->pc).second)
>> + if (addr_hash.insert (target_call_site->pc ()).second)
>> {
>> /* Successfully entered TARGET_CALL_SITE. */
>>
>> @@ -1005,7 +1005,7 @@ call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
>> call_site = chain.back ();
>> chain.pop_back ();
>>
>> - size_t removed = addr_hash.erase (call_site->pc);
>> + size_t removed = addr_hash.erase (call_site->pc ());
>> gdb_assert (removed == 1);
>>
>> target_call_site = call_site->tail_call_next;
>> diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
>> index ac8460df9a4..d0460674d10 100644
>> --- a/gdb/dwarf2/read.c
>> +++ b/gdb/dwarf2/read.c
>> @@ -13405,7 +13405,7 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
>> + (sizeof (*call_site->parameter) * (nparams - 1))));
>> *slot = call_site;
>> memset (call_site, 0, sizeof (*call_site) - sizeof (*call_site->parameter));
>> - call_site->pc = pc;
>> + call_site->m_pc = pc;
>
> I did this as a quick hack in my proof of concept patch, but I think we
> should make this a bit nicer than setting the (conceptually) private
> field here. We can have add a constructor to call_site and use
> placement new, see patch below (only built-tested).
>
>

Ack, integrated in patch, and renamed $subject to indicate larger scope
of patch.

Also some trivial updates due to commit "[gdb/symtab] Add call_site_eq
and call_site_hash".

Committed as attached.

Thanks,
- Tom

[-- Attachment #2: 0002-gdb-symtab-C-ify-call_site.patch --]
[-- Type: text/x-patch, Size: 10646 bytes --]

[gdb/symtab] C++-ify call_site

- add constructor
- add member function call_site::pc ()

Tested on x86_64-linux.

Co-Authored-By: Tom de Vries <tdevries@suse.de>

---
gdb/dwarf2/frame-tailcall.c | 4 +--
gdb/dwarf2/loc.c | 18 ++++++------
gdb/dwarf2/read.c | 27 +++++++++---------
gdb/gdbtypes.c | 9 ++++++
gdb/gdbtypes.h | 67 +++++++++++++++++++++++++++++----------------
gdb/symtab.c | 3 +-
6 files changed, 77 insertions(+), 51 deletions(-)

diff --git a/gdb/dwarf2/frame-tailcall.c b/gdb/dwarf2/frame-tailcall.c
index f112b4ecca4..9fe498b0924 100644
--- a/gdb/dwarf2/frame-tailcall.c
+++ b/gdb/dwarf2/frame-tailcall.c
@@ -240,14 +240,14 @@ pretend_pc (struct frame_info *this_frame, struct tailcall_cache *cache)
gdb_assert (next_levels >= 0);

if (next_levels < chain->callees)
- return chain->call_site[chain->length - next_levels - 1]->pc;
+ return chain->call_site[chain->length - next_levels - 1]->pc ();
next_levels -= chain->callees;

/* Otherwise CHAIN->CALLEES are already covered by CHAIN->CALLERS. */
if (chain->callees != chain->length)
{
if (next_levels < chain->callers)
- return chain->call_site[chain->callers - next_levels - 1]->pc;
+ return chain->call_site[chain->callers - next_levels - 1]->pc ();
next_levels -= chain->callers;
}

diff --git a/gdb/dwarf2/loc.c b/gdb/dwarf2/loc.c
index 2322a01f396..27a1c97682a 100644
--- a/gdb/dwarf2/loc.c
+++ b/gdb/dwarf2/loc.c
@@ -654,10 +654,10 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
{
struct bound_minimal_symbol msym;

- msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
+ msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
throw_error (NO_ENTRY_VALUE_ERROR,
_("DW_AT_call_target is not specified at %s in %s"),
- paddress (call_site_gdbarch, call_site->pc),
+ paddress (call_site_gdbarch, call_site->pc ()),
(msym.minsym == NULL ? "???"
: msym.minsym->print_name ()));

@@ -666,12 +666,12 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
{
struct bound_minimal_symbol msym;

- msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
+ msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
throw_error (NO_ENTRY_VALUE_ERROR,
_("DW_AT_call_target DWARF block resolving "
"requires known frame which is currently not "
"available at %s in %s"),
- paddress (call_site_gdbarch, call_site->pc),
+ paddress (call_site_gdbarch, call_site->pc ()),
(msym.minsym == NULL ? "???"
: msym.minsym->print_name ()));

@@ -700,11 +700,11 @@ call_site_to_target_addr (struct gdbarch *call_site_gdbarch,
msym = lookup_minimal_symbol (physname, NULL, NULL);
if (msym.minsym == NULL)
{
- msym = lookup_minimal_symbol_by_pc (call_site->pc - 1);
+ msym = lookup_minimal_symbol_by_pc (call_site->pc () - 1);
throw_error (NO_ENTRY_VALUE_ERROR,
_("Cannot find function \"%s\" for a call site target "
"at %s in %s"),
- physname, paddress (call_site_gdbarch, call_site->pc),
+ physname, paddress (call_site_gdbarch, call_site->pc ()),
(msym.minsym == NULL ? "???"
: msym.minsym->print_name ()));

@@ -810,7 +810,7 @@ func_verify_no_selftailcall (struct gdbarch *gdbarch, CORE_ADDR verify_addr)
static void
tailcall_dump (struct gdbarch *gdbarch, const struct call_site *call_site)
{
- CORE_ADDR addr = call_site->pc;
+ CORE_ADDR addr = call_site->pc ();
struct bound_minimal_symbol msym = lookup_minimal_symbol_by_pc (addr - 1);

fprintf_unfiltered (gdb_stdlog, " %s(%s)", paddress (gdbarch, addr),
@@ -986,7 +986,7 @@ call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,

if (target_call_site)
{
- if (addr_hash.insert (target_call_site->pc).second)
+ if (addr_hash.insert (target_call_site->pc ()).second)
{
/* Successfully entered TARGET_CALL_SITE. */

@@ -1005,7 +1005,7 @@ call_site_find_chain_1 (struct gdbarch *gdbarch, CORE_ADDR caller_pc,
call_site = chain.back ();
chain.pop_back ();

- size_t removed = addr_hash.erase (call_site->pc);
+ size_t removed = addr_hash.erase (call_site->pc ());
gdb_assert (removed == 1);

target_call_site = call_site->tail_call_next;
diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index f8421aeb344..230eb6a04b1 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -13341,7 +13341,6 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
struct gdbarch *gdbarch = objfile->arch ();
CORE_ADDR pc, baseaddr;
struct attribute *attr;
- struct call_site *call_site, call_site_local;
void **slot;
int nparams;
struct die_info *child_die;
@@ -13366,10 +13365,11 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
pc = gdbarch_adjust_dwarf2_addr (gdbarch, pc);

if (cu->call_site_htab == NULL)
- cu->call_site_htab = htab_create_alloc_ex (16, call_site_hash, call_site_eq,
- NULL, &objfile->objfile_obstack,
+ cu->call_site_htab = htab_create_alloc_ex (16, call_site::hash,
+ call_site::eq, NULL,
+ &objfile->objfile_obstack,
hashtab_obstack_allocate, NULL);
- call_site_local.pc = pc;
+ struct call_site call_site_local (pc, nullptr, nullptr);
slot = htab_find_slot (cu->call_site_htab, &call_site_local, INSERT);
if (*slot != NULL)
{
@@ -13399,14 +13399,16 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
nparams++;
}

- call_site
- = ((struct call_site *)
- obstack_alloc (&objfile->objfile_obstack,
- sizeof (*call_site)
- + (sizeof (*call_site->parameter) * (nparams - 1))));
+ struct call_site *call_site
+ = new (XOBNEWVAR (&objfile->objfile_obstack,
+ struct call_site,
+ sizeof (*call_site) + sizeof (call_site->parameter[0]) * nparams))
+ struct call_site (pc, cu->per_cu, per_objfile);
*slot = call_site;
- memset (call_site, 0, sizeof (*call_site) - sizeof (*call_site->parameter));
- call_site->pc = pc;
+
+ /* We never call the destructor of call_site, so we must ensure it is
+ trivially destructible. */
+ gdb_static_assert(std::is_trivially_destructible<struct call_site>::value);

if (dwarf2_flag_true_p (die, DW_AT_call_tail_call, cu)
|| dwarf2_flag_true_p (die, DW_AT_GNU_tail_call, cu))
@@ -13527,9 +13529,6 @@ read_call_site_scope (struct die_info *die, struct dwarf2_cu *cu)
"block nor reference, for DIE %s [in module %s]"),
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;
child_die = child_die->sibling)
diff --git a/gdb/gdbtypes.c b/gdb/gdbtypes.c
index 97f016fccd1..8954c370b7b 100644
--- a/gdb/gdbtypes.c
+++ b/gdb/gdbtypes.c
@@ -37,6 +37,7 @@
#include "cp-support.h"
#include "bcache.h"
#include "dwarf2/loc.h"
+#include "dwarf2/read.h"
#include "gdbcore.h"
#include "floatformat.h"
#include "f-lang.h"
@@ -6308,6 +6309,14 @@ objfile_type (struct objfile *objfile)
return objfile_type;
}

+/* See gdbtypes.h. */
+
+CORE_ADDR
+call_site::pc () const
+{
+ return m_pc;
+}
+
void _initialize_gdbtypes ();
void
_initialize_gdbtypes ()
diff --git a/gdb/gdbtypes.h b/gdb/gdbtypes.h
index 8021cb21ecc..5fe10cb7f1e 100644
--- a/gdb/gdbtypes.h
+++ b/gdb/gdbtypes.h
@@ -1793,52 +1793,71 @@ struct call_site_parameter

struct call_site
{
- /* Address of the first instruction after this call. */
-
- CORE_ADDR pc;
+ call_site (CORE_ADDR pc, dwarf2_per_cu_data *per_cu,
+ dwarf2_per_objfile *per_objfile)
+ : per_cu (per_cu), per_objfile (per_objfile), m_pc (pc)
+ {}
+
+ static int
+ eq (const call_site *a, const call_site *b)
+ {
+ return core_addr_eq (&a->m_pc, &b->m_pc);
+ }
+
+ static hashval_t
+ hash (const call_site *a)
+ {
+ return core_addr_hash (&a->m_pc);
+ }
+
+ static int
+ eq (const void *a, const void *b)
+ {
+ return eq ((const call_site *)a, (const call_site *)b);
+ }
+
+ static hashval_t
+ hash (const void *a)
+ {
+ return hash ((const call_site *)a);
+ }
+
+ /* Return the address of the first instruction after this call. */
+
+ CORE_ADDR pc () const;

/* * List successor with head in FUNC_TYPE.TAIL_CALL_LIST. */

- struct call_site *tail_call_next;
+ struct call_site *tail_call_next = nullptr;

/* * Describe DW_AT_call_target. Missing attribute uses
FIELD_LOC_KIND_DWARF_BLOCK with FIELD_DWARF_BLOCK == NULL. */

- struct call_site_target target;
+ struct call_site_target target {};

/* * Size of the PARAMETER array. */

- unsigned parameter_count;
+ unsigned parameter_count = 0;

/* * CU of the function where the call is located. It gets used
for DWARF blocks execution in the parameter array below. */

- dwarf2_per_cu_data *per_cu;
+ dwarf2_per_cu_data *const per_cu = nullptr;

/* objfile of the function where the call is located. */

- dwarf2_per_objfile *per_objfile;
+ dwarf2_per_objfile *const per_objfile = nullptr;

+ private:
+ /* Address of the first instruction after this call. */
+ const CORE_ADDR m_pc;
+
+ public:
/* * Describe DW_TAG_call_site's DW_TAG_formal_parameter. */

- struct call_site_parameter parameter[1];
+ struct call_site_parameter parameter[];
};

-static inline int
-call_site_eq (const void *a_, const void *b_)
-{
- const struct call_site *a = (const call_site *)a_;
- const struct call_site *b = (const call_site *)b_;
- return core_addr_eq (&a->pc, &b->pc);
-}
-
-static inline hashval_t
-call_site_hash (const void *a_)
-{
- const struct call_site *a = (const call_site *)a_;
- return core_addr_hash (&a->pc);
-}
-
/* The type-specific info for TYPE_CODE_FIXED_POINT types. */

struct fixed_point_type_info
diff --git a/gdb/symtab.c b/gdb/symtab.c
index bd1eb429b94..cb583846efa 100644
--- a/gdb/symtab.c
+++ b/gdb/symtab.c
@@ -334,11 +334,10 @@ search_domain_name (enum search_domain e)
call_site *
compunit_symtab::find_call_site (CORE_ADDR pc) const
{
- struct call_site call_site_local;
if (m_call_site_htab == nullptr)
return nullptr;

- call_site_local.pc = pc;
+ struct call_site call_site_local (pc, nullptr, nullptr);
void **slot
= htab_find_slot (m_call_site_htab, &call_site_local, NO_INSERT);
if (slot == nullptr)