Files
clang-p2996/lldb/tools/debugserver/source/DNBBreakpoint.cpp
Greg Clayton d8cf1a119d Huge performance improvements when one breakpoint contains many locations.
325,000 breakpoints for running "breakpoint set --func-regex ." on lldb itself (after hitting a breakpoint at main so that LLDB.framework is loaded) used to take up to an hour to set, now we are down under a minute. With warm file caches, we are at 40 seconds, and that is with setting 325,000 breakpoint through the GDB remote API. Linux and the native debuggers might be faster. I haven't timed what how much is debug info parsing and how much is the protocol traffic to/from GDB remote.

That there were many performance issues. Most of them were due to storing breakpoints in the wrong data structures, or using the wrong iterators to traverse the lists, traversing the lists in inefficient ways, and not optimizing certain function name lookups/symbol merges correctly.

Debugging after that is also now very efficient. There were issues with replacing the breakpoint opcodes in memory that was read, and those routines were also fixed.

llvm-svn: 183820
2013-06-12 00:46:38 +00:00

226 lines
6.3 KiB
C++

//===-- DNBBreakpoint.cpp ---------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Created by Greg Clayton on 6/29/07.
//
//===----------------------------------------------------------------------===//
#include "DNBBreakpoint.h"
#include "MachProcess.h"
#include <assert.h>
#include <algorithm>
#include <inttypes.h>
#include "DNBLog.h"
#pragma mark -- DNBBreakpoint
DNBBreakpoint::DNBBreakpoint(nub_addr_t addr, nub_size_t byte_size, bool hardware) :
m_retain_count (1),
m_byte_size (byte_size),
m_opcode(),
m_addr(addr),
m_enabled(0),
m_hw_preferred(hardware),
m_is_watchpoint(0),
m_watch_read(0),
m_watch_write(0),
m_hw_index(INVALID_NUB_HW_INDEX)
{
}
DNBBreakpoint::~DNBBreakpoint()
{
}
void
DNBBreakpoint::Dump() const
{
if (IsBreakpoint())
{
DNBLog ("DNBBreakpoint addr = 0x%llx state = %s type = %s breakpoint hw_index = %i",
(uint64_t)m_addr,
m_enabled ? "enabled " : "disabled",
IsHardware() ? "hardware" : "software",
GetHardwareIndex());
}
else
{
DNBLog ("DNBBreakpoint addr = 0x%llx size = %llu state = %s type = %s watchpoint (%s%s) hw_index = %i",
(uint64_t)m_addr,
(uint64_t)m_byte_size,
m_enabled ? "enabled " : "disabled",
IsHardware() ? "hardware" : "software",
m_watch_read ? "r" : "",
m_watch_write ? "w" : "",
GetHardwareIndex());
}
}
#pragma mark -- DNBBreakpointList
DNBBreakpointList::DNBBreakpointList()
{
}
DNBBreakpointList::~DNBBreakpointList()
{
}
DNBBreakpoint *
DNBBreakpointList::Add(nub_addr_t addr, nub_size_t length, bool hardware)
{
m_breakpoints.insert(std::make_pair(addr, DNBBreakpoint(addr, length, hardware)));
iterator pos = m_breakpoints.find (addr);
return &pos->second;
}
bool
DNBBreakpointList::Remove (nub_addr_t addr)
{
iterator pos = m_breakpoints.find(addr);
if (pos != m_breakpoints.end())
{
m_breakpoints.erase(pos);
return true;
}
return false;
}
DNBBreakpoint *
DNBBreakpointList::FindByAddress (nub_addr_t addr)
{
iterator pos = m_breakpoints.find(addr);
if (pos != m_breakpoints.end())
return &pos->second;
return NULL;
}
const DNBBreakpoint *
DNBBreakpointList::FindByAddress (nub_addr_t addr) const
{
const_iterator pos = m_breakpoints.find(addr);
if (pos != m_breakpoints.end())
return &pos->second;
return NULL;
}
// Finds the next breakpoint at an address greater than or equal to "addr"
size_t
DNBBreakpointList::FindBreakpointsThatOverlapRange (nub_addr_t addr,
nub_addr_t size,
std::vector<DNBBreakpoint *> &bps)
{
bps.clear();
iterator end = m_breakpoints.end();
// Find the first breakpoint with an address >= to "addr"
iterator pos = m_breakpoints.lower_bound(addr);
if (pos != end)
{
if (pos != m_breakpoints.begin())
{
// Watch out for a breakpoint at an address less than "addr" that might still overlap
iterator prev_pos = pos;
--prev_pos;
if (prev_pos->second.IntersectsRange (addr, size, NULL, NULL, NULL))
bps.push_back (&pos->second);
}
while (pos != end)
{
// When we hit a breakpoint whose start address is greater than "addr + size" we are done.
// Do the math in a way that doesn't risk unsigned overflow with bad input.
if ((pos->second.Address() - addr) >= size)
break;
// Check if this breakpoint overlaps, and if it does, add it to the list
if (pos->second.IntersectsRange (addr, size, NULL, NULL, NULL))
{
bps.push_back (&pos->second);
++pos;
}
}
}
return bps.size();
}
void
DNBBreakpointList::Dump() const
{
const_iterator pos;
const_iterator end = m_breakpoints.end();
for (pos = m_breakpoints.begin(); pos != end; ++pos)
pos->second.Dump();
}
void
DNBBreakpointList::DisableAll ()
{
iterator pos, end = m_breakpoints.end();
for (pos = m_breakpoints.begin(); pos != end; ++pos)
pos->second.SetEnabled(false);
}
void
DNBBreakpointList::RemoveTrapsFromBuffer (nub_addr_t addr, nub_size_t size, void *p) const
{
uint8_t *buf = (uint8_t *)p;
const_iterator end = m_breakpoints.end();
const_iterator pos = m_breakpoints.lower_bound(addr);
while (pos != end && (pos->first < (addr + size)))
{
nub_addr_t intersect_addr;
nub_size_t intersect_size;
nub_size_t opcode_offset;
const DNBBreakpoint &bp = pos->second;
if (bp.IntersectsRange(addr, size, &intersect_addr, &intersect_size, &opcode_offset))
{
assert(addr <= intersect_addr && intersect_addr < addr + size);
assert(addr < intersect_addr + intersect_size && intersect_addr + intersect_size <= addr + size);
assert(opcode_offset + intersect_size <= bp.ByteSize());
nub_size_t buf_offset = intersect_addr - addr;
::memcpy(buf + buf_offset, bp.SavedOpcodeBytes() + opcode_offset, intersect_size);
}
++pos;
}
}
void
DNBBreakpointList::DisableAllBreakpoints(MachProcess *process)
{
iterator pos, end = m_breakpoints.end();
for (pos = m_breakpoints.begin(); pos != end; ++pos)
process->DisableBreakpoint(pos->second.Address(), false);
}
void
DNBBreakpointList::DisableAllWatchpoints(MachProcess *process)
{
iterator pos, end = m_breakpoints.end();
for (pos = m_breakpoints.begin(); pos != end; ++pos)
process->DisableWatchpoint(pos->second.Address(), false);
}
void
DNBBreakpointList::RemoveDisabled()
{
iterator pos = m_breakpoints.begin();
while (pos != m_breakpoints.end())
{
if (!pos->second.IsEnabled())
pos = m_breakpoints.erase(pos);
else
++pos;
}
}