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* dwarf_reader.cc (next_generation_count): New static var.

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(Addr2line_cache_entry): New struct.
	(addr2line_cache): New static var.
	(Dwarf_line_info::one_addr2line): Added caching.
	(Dwarf_line_info::clear_addr2line_cache): New function.
	* dwarf_reader.h (Dwarf_line_info::one_addr2line): Add
	cache-size parameter.
	(Dwarf_line_info::one_addr2line_cache): New function.
	* symtab.cc (Symbol_table::detect_odr_violations): Pass
	new cache-size argument to one_addr2line(), and clear cache.
This commit is contained in:
Craig Silverstein
2008-05-01 00:25:33 +00:00
parent f089c43345
commit e4e5049b7b
4 changed files with 134 additions and 23 deletions
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118
gold/dwarf_reader.cc
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@@ -23,6 +23,7 @@
#include "gold.h"
#include <algorithm>
#include <vector>
#include "elfcpp_swap.h"
#include "dwarf.h"
@@ -799,35 +800,120 @@ Sized_dwarf_line_info<size, big_endian>::do_addr2line(unsigned int shndx,
// Dwarf_line_info routines.
static unsigned int next_generation_count = 0;
struct Addr2line_cache_entry
{
Object* object;
unsigned int shndx;
Dwarf_line_info* dwarf_line_info;
unsigned int generation_count;
unsigned int access_count;
Addr2line_cache_entry(Object* o, unsigned int s, Dwarf_line_info* d)
: object(o), shndx(s), dwarf_line_info(d),
generation_count(next_generation_count), access_count(0)
{
if (next_generation_count < (1U << 31))
++next_generation_count;
}
};
// We expect this cache to be small, so don't bother with a hashtable
// or priority queue or anything: just use a simple vector.
static std::vector<Addr2line_cache_entry> addr2line_cache;
std::string
Dwarf_line_info::one_addr2line(Object* object,
unsigned int shndx, off_t offset)
unsigned int shndx, off_t offset,
size_t cache_size)
{
switch (parameters->size_and_endianness())
Dwarf_line_info* lineinfo = NULL;
std::vector<Addr2line_cache_entry>::iterator it;
// First, check the cache. If we hit, update the counts.
for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it)
{
if (it->object == object && it->shndx == shndx)
{
lineinfo = it->dwarf_line_info;
it->generation_count = next_generation_count;
// We cap generation_count at 2^31 -1 to avoid overflow.
if (next_generation_count < (1U << 31))
++next_generation_count;
// We cap access_count at 31 so 2^access_count doesn't overflow
if (it->access_count < 31)
++it->access_count;
break;
}
}
// If we don't hit the cache, create a new object and insert into the
// cache.
if (lineinfo == NULL)
{
switch (parameters->size_and_endianness())
{
#ifdef HAVE_TARGET_32_LITTLE
case Parameters::TARGET_32_LITTLE:
return Sized_dwarf_line_info<32, false>(object, shndx).addr2line(shndx,
offset);
case Parameters::TARGET_32_LITTLE:
lineinfo = new Sized_dwarf_line_info<32, false>(object, shndx); break;
#endif
#ifdef HAVE_TARGET_32_BIG
case Parameters::TARGET_32_BIG:
return Sized_dwarf_line_info<32, true>(object, shndx).addr2line(shndx,
offset);
case Parameters::TARGET_32_BIG:
lineinfo = new Sized_dwarf_line_info<32, true>(object, shndx); break;
#endif
#ifdef HAVE_TARGET_64_LITTLE
case Parameters::TARGET_64_LITTLE:
return Sized_dwarf_line_info<64, false>(object, shndx).addr2line(shndx,
offset);
case Parameters::TARGET_64_LITTLE:
lineinfo = new Sized_dwarf_line_info<64, false>(object, shndx); break;
#endif
#ifdef HAVE_TARGET_64_BIG
case Parameters::TARGET_64_BIG:
return Sized_dwarf_line_info<64, true>(object, shndx).addr2line(shndx,
offset);
case Parameters::TARGET_64_BIG:
lineinfo = new Sized_dwarf_line_info<64, true>(object, shndx); break;
#endif
default:
gold_unreachable();
default:
gold_unreachable();
}
addr2line_cache.push_back(Addr2line_cache_entry(object, shndx, lineinfo));
}
// Now that we have our object, figure out the answer
std::string retval = lineinfo->addr2line(shndx, offset);
// Finally, if our cache has grown too big, delete old objects. We
// assume the common (probably only) case is deleting only one object.
// We use a pretty simple scheme to evict: function of LRU and MFU.
while (addr2line_cache.size() > cache_size)
{
unsigned int lowest_score = ~0U;
std::vector<Addr2line_cache_entry>::iterator lowest
= addr2line_cache.end();
for (it = addr2line_cache.begin(); it != addr2line_cache.end(); ++it)
{
const unsigned int score = (it->generation_count
+ (1U << it->access_count));
if (score < lowest_score)
{
lowest_score = score;
lowest = it;
}
}
if (lowest != addr2line_cache.end())
{
delete lowest->dwarf_line_info;
addr2line_cache.erase(lowest);
}
}
return retval;
}
void
Dwarf_line_info::clear_addr2line_cache()
{
for (std::vector<Addr2line_cache_entry>::iterator it = addr2line_cache.begin();
it != addr2line_cache.end();
++it)
delete it->dwarf_line_info;
addr2line_cache.clear();
}
#ifdef HAVE_TARGET_32_LITTLE