[PATCH 16/22] Remove dwarf2_cu::base_known

Tom Tromey
2020-03-22T18:45:29Z

This removes dwarf2_cu::base_known, changing base_address to be a
gdb::optional.

gdb/ChangeLog
2020-03-22 Tom Tromey <tom@tromey.com>

* dwarf2/read.c (struct dwarf2_cu) <base_known>: Remove.
<base_address>: Now an optional.
(dwarf2_find_base_address, dwarf2_rnglists_process)
(dwarf2_ranges_process, fill_in_loclist_baton)
(dwarf2_symbol_mark_computed): Update.
---
gdb/ChangeLog | 8 ++++++++
gdb/dwarf2/read.c | 47 +++++++++++++++++------------------------------
2 files changed, 25 insertions(+), 30 deletions(-)

diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c
index 8b9b6bc3ea0..3479cd55a2e 100644
--- a/gdb/dwarf2/read.c
+++ b/gdb/dwarf2/read.c
@@ -393,10 +393,7 @@ struct dwarf2_cu
struct comp_unit_head header {};

/* Base address of this compilation unit. */
- CORE_ADDR base_address = 0;
-
- /* Non-zero if base_address has been set. */
- int base_known = 0;
+ gdb::optional<CORE_ADDR> base_address;

/* The language we are debugging. */
enum language language = language_unknown;
@@ -5783,23 +5780,16 @@ dwarf2_find_base_address (struct die_info *die, struct dwarf2_cu *cu)
{
struct attribute *attr;

- cu->base_known = 0;
- cu->base_address = 0;
+ cu->base_address.reset ();

attr = dwarf2_attr (die, DW_AT_entry_pc, cu);
if (attr != nullptr)
- {
- cu->base_address = attr->value_as_address ();
- cu->base_known = 1;
- }
+ cu->base_address = attr->value_as_address ();
else
{
attr = dwarf2_attr (die, DW_AT_low_pc, cu);
if (attr != nullptr)
- {
- cu->base_address = attr->value_as_address ();
- cu->base_known = 1;
- }
+ cu->base_address = attr->value_as_address ();
}
}

@@ -13441,13 +13431,11 @@ dwarf2_rnglists_process (unsigned offset, struct dwarf2_cu *cu,
struct objfile *objfile = dwarf2_per_objfile->objfile;
bfd *obfd = objfile->obfd;
/* Base address selection entry. */
- CORE_ADDR base;
- int found_base;
+ gdb::optional<CORE_ADDR> base;
const gdb_byte *buffer;
CORE_ADDR baseaddr;
bool overflow = false;

- found_base = cu->base_known;
base = cu->base_address;

dwarf2_per_objfile->rnglists.read (objfile);
@@ -13486,7 +13474,6 @@ dwarf2_rnglists_process (unsigned offset, struct dwarf2_cu *cu,
break;
}
base = cu->header.read_address (obfd, buffer, &bytes_read);
- found_base = 1;
buffer += bytes_read;
break;
case DW_RLE_start_length:
@@ -13544,7 +13531,7 @@ dwarf2_rnglists_process (unsigned offset, struct dwarf2_cu *cu,
if (rlet == DW_RLE_base_address)
continue;

- if (!found_base)
+ if (!base.has_value ())
{
/* We have no valid base address for the ranges
data. */
@@ -13563,8 +13550,8 @@ dwarf2_rnglists_process (unsigned offset, struct dwarf2_cu *cu,
if (range_beginning == range_end)
continue;

- range_beginning += base;
- range_end += base;
+ range_beginning += *base;
+ range_end += *base;

/* A not-uncommon case of bad debug info.
Don't pollute the addrmap with bad data. */
@@ -13608,8 +13595,7 @@ dwarf2_ranges_process (unsigned offset, struct dwarf2_cu *cu,
unsigned int addr_size = cu_header->addr_size;
CORE_ADDR mask = ~(~(CORE_ADDR)1 << (addr_size * 8 - 1));
/* Base address selection entry. */
- CORE_ADDR base;
- int found_base;
+ gdb::optional<CORE_ADDR> base;
unsigned int dummy;
const gdb_byte *buffer;
CORE_ADDR baseaddr;
@@ -13617,7 +13603,6 @@ dwarf2_ranges_process (unsigned offset, struct dwarf2_cu *cu,
if (cu_header->version >= 5)
return dwarf2_rnglists_process (offset, cu, callback);

- found_base = cu->base_known;
base = cu->base_address;

dwarf2_per_objfile->ranges.read (objfile);
@@ -13654,11 +13639,10 @@ dwarf2_ranges_process (unsigned offset, struct dwarf2_cu *cu,
/* If we found the largest possible address, then we already
have the base address in range_end. */
base = range_end;
- found_base = 1;
continue;
}

- if (!found_base)
+ if (!base.has_value ())
{
/* We have no valid base address for the ranges
data. */
@@ -13677,8 +13661,8 @@ dwarf2_ranges_process (unsigned offset, struct dwarf2_cu *cu,
if (range_beginning == range_end)
continue;

- range_beginning += base;
- range_end += base;
+ range_beginning += *base;
+ range_end += *base;

/* A not-uncommon case of bad debug info.
Don't pollute the addrmap with bad data. */
@@ -22758,7 +22742,10 @@ fill_in_loclist_baton (struct dwarf2_cu *cu,
don't run off the edge of the section. */
baton->size = section->size - DW_UNSND (attr);
baton->data = section->buffer + DW_UNSND (attr);
- baton->base_address = cu->base_address;
+ if (cu->base_address.has_value ())
+ baton->base_address = *cu->base_address;
+ else
+ baton->base_address = 0;
baton->from_dwo = cu->dwo_unit != NULL;
}

@@ -22783,7 +22770,7 @@ dwarf2_symbol_mark_computed (const struct attribute *attr, struct symbol *sym,

fill_in_loclist_baton (cu, baton, attr);

- if (cu->base_known == 0)
+ if (!cu->base_address.has_value ())
complaint (_("Location list used without "
"specifying the CU base address."));

--
2.17.2