#include "gold.h"
#include <algorithm>
+#include <vector>
#include "elfcpp_swap.h"
#include "dwarf.h"
// 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
addr2line(unsigned int shndx, off_t offset)
{ return do_addr2line(shndx, offset); }
- // A helper function for a single addr2line lookup. It uses
- // parameters() to figure out the size and endianness. This is less
- // efficient than using the templatized size and endianness, so only
- // call this from an un-templatized context.
+ // A helper function for a single addr2line lookup. It also keeps a
+ // cache of the last CACHE_SIZE Dwarf_line_info objects it created;
+ // set to 0 not to cache at all. The larger CACHE_SIZE is, the more
+ // chance this routine won't have to re-create a Dwarf_line_info
+ // object for its addr2line computation; such creations are slow.
+ // NOTE: Not thread-safe, so only call from one thread at a time.
static std::string
- one_addr2line(Object* object, unsigned int shndx, off_t offset);
+ one_addr2line(Object* object, unsigned int shndx, off_t offset,
+ size_t cache_size);
+
+ // This reclaims all the memory that one_addr2line may have cached.
+ // Use this when you know you will not be calling one_addr2line again.
+ static void
+ clear_addr2line_cache();
private:
virtual std::string
// want to run this in a general Task for better
// performance, we will need one Task for object, plus
// appropriate locking to ensure that we don't conflict with
- // other uses of the object.
+ // other uses of the object. Also note, one_addr2line is not
+ // currently thread-safe.
Task_lock_obj<Object> tl(task, locs->object);
+ // 16 is the size of the object-cache that one_addr2line should use.
std::string lineno = Dwarf_line_info::one_addr2line(
- locs->object, locs->shndx, locs->offset);
+ locs->object, locs->shndx, locs->offset, 16);
if (!lineno.empty())
line_nums.insert(lineno);
}
fprintf(stderr, " %s\n", it2->c_str());
}
}
+ // We only call one_addr2line() in this function, so we can clear its cache.
+ Dwarf_line_info::clear_addr2line_cache();
}
// Warnings functions.
projects / deliverable / binutils-gdb.git / commitdiff
