//===-- DWARFDebugArangeSet.cpp ---------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "DWARFDebugArangeSet.h"
#include <assert.h>
#include "lldb/Core/Stream.h"
#include "SymbolFileDWARF.h"
using namespace lldb_private;
DWARFDebugArangeSet::DWARFDebugArangeSet() :
m_offset(DW_INVALID_OFFSET),
m_header(),
m_arange_descriptors()
{
m_header.length = 0;
m_header.version = 0;
m_header.cu_offset = 0;
m_header.addr_size = 0;
m_header.seg_size = 0;
}
void
DWARFDebugArangeSet::Clear()
{
m_offset = DW_INVALID_OFFSET;
m_header.length = 0;
m_header.version = 0;
m_header.cu_offset = 0;
m_header.addr_size = 0;
m_header.seg_size = 0;
m_arange_descriptors.clear();
}
void
DWARFDebugArangeSet::SetHeader
(
uint16_t version,
uint32_t cu_offset,
uint8_t addr_size,
uint8_t seg_size
)
{
m_header.version = version;
m_header.cu_offset = cu_offset;
m_header.addr_size = addr_size;
m_header.seg_size = seg_size;
}
void
DWARFDebugArangeSet::Compact()
{
if (m_arange_descriptors.empty())
return;
// Iterate through all arange descriptors and combine any ranges that
// overlap or have matching boundaries. The m_arange_descriptors are assumed
// to be in ascending order after being built by adding descriptors
// using the AddDescriptor method.
uint32_t i = 0;
while (i + 1 < m_arange_descriptors.size())
{
if (m_arange_descriptors[i].end_address() >= m_arange_descriptors[i+1].address)
{
// The current range ends at or exceeds the start of the next address range.
// Compute the max end address between the two and use that to make the new
// length.
const dw_addr_t max_end_addr = std::max(m_arange_descriptors[i].end_address(), m_arange_descriptors[i+1].end_address());
m_arange_descriptors[i].length = max_end_addr - m_arange_descriptors[i].address;
// Now remove the next entry as it was just combined with the previous one.
m_arange_descriptors.erase(m_arange_descriptors.begin()+i+1);
}
else
{
// Discontiguous address range, just proceed to the next one.
++i;
}
}
}
//----------------------------------------------------------------------
// Compare function DWARFDebugArangeSet::Descriptor structures
//----------------------------------------------------------------------
static bool DescriptorLessThan (const DWARFDebugArangeSet::Descriptor& range1, const DWARFDebugArangeSet::Descriptor& range2)
{
return range1.address < range2.address;
}
//----------------------------------------------------------------------
// Add a range descriptor and keep things sorted so we can easily
// compact the ranges before being saved or used.
//----------------------------------------------------------------------
void
DWARFDebugArangeSet::AddDescriptor(const DWARFDebugArangeSet::Descriptor& range)
{
if (m_arange_descriptors.empty())
{
m_arange_descriptors.push_back(range);
return;
}
DescriptorIter end = m_arange_descriptors.end();
DescriptorIter pos = lower_bound(m_arange_descriptors.begin(), end, range, DescriptorLessThan);
const dw_addr_t range_end_addr = range.end_address();
if (pos != end)
{
const dw_addr_t found_end_addr = pos->end_address();
if (range.address < pos->address)
{
if (range_end_addr < pos->address)
{
// Non-contiguous entries, add this one before the found entry
m_arange_descriptors.insert(pos, range);
}
else if (range_end_addr == pos->address)
{
// The top end of 'range' is the lower end of the entry
// pointed to by 'pos'. We can combine range with the
// entry we found by setting the starting address and
// increasing the length since they don't overlap.
pos->address = range.address;
pos->length += range.length;
}
else
{
// We can combine these two and make sure the largest end
// address is used to make end address.
pos->address = range.address;
pos->length = std::max(found_end_addr, range_end_addr) - pos->address;
}
}
else if (range.address == pos->address)
{
pos->length = std::max(pos->length, range.length);
}
}
else
{
// NOTE: 'pos' points to entry past the end which is ok for insert,
// don't use otherwise!!!
const dw_addr_t max_addr = m_arange_descriptors.back().end_address();
if (max_addr < range.address)
{
// Non-contiguous entries, add this one before the found entry
m_arange_descriptors.insert(pos, range);
}
else if (max_addr == range.address)
{
m_arange_descriptors.back().length += range.length;
}
else
{
m_arange_descriptors.back().length = std::max(max_addr, range_end_addr) - m_arange_descriptors.back().address;
}
}
}
bool
DWARFDebugArangeSet::Extract(const DataExtractor &data, lldb::offset_t *offset_ptr)
{
if (data.ValidOffset(*offset_ptr))
{
m_arange_descriptors.clear();
m_offset = *offset_ptr;
// 7.20 Address Range Table
//
// Each set of entries in the table of address ranges contained in
// the .debug_aranges section begins with a header consisting of: a
// 4-byte length containing the length of the set of entries for this
// compilation unit, not including the length field itself; a 2-byte
// version identifier containing the value 2 for DWARF Version 2; a
// 4-byte offset into the.debug_infosection; a 1-byte unsigned integer
// containing the size in bytes of an address (or the offset portion of
// an address for segmented addressing) on the target system; and a
// 1-byte unsigned integer containing the size in bytes of a segment
// descriptor on the target system. This header is followed by a series
// of tuples. Each tuple consists of an address and a length, each in
// the size appropriate for an address on the target architecture.
m_header.length = data.GetU32(offset_ptr);
m_header.version = data.GetU16(offset_ptr);
m_header.cu_offset = data.GetU32(offset_ptr);
m_header.addr_size = data.GetU8(offset_ptr);
m_header.seg_size = data.GetU8(offset_ptr);
// The first tuple following the header in each set begins at an offset
// that is a multiple of the size of a single tuple (that is, twice the
// size of an address). The header is padded, if necessary, to the
// appropriate boundary.
const uint32_t header_size = *offset_ptr - m_offset;
const uint32_t tuple_size = m_header.addr_size << 1;
uint32_t first_tuple_offset = 0;
while (first_tuple_offset < header_size)
first_tuple_offset += tuple_size;
*offset_ptr = m_offset + first_tuple_offset;
Descriptor arangeDescriptor;
assert(sizeof(arangeDescriptor.address) == sizeof(arangeDescriptor.length));
assert(sizeof(arangeDescriptor.address) >= m_header.addr_size);
while (data.ValidOffset(*offset_ptr))
{
arangeDescriptor.address = data.GetMaxU64(offset_ptr, m_header.addr_size);
arangeDescriptor.length = data.GetMaxU64(offset_ptr, m_header.addr_size);
// Each set of tuples is terminated by a 0 for the address and 0
// for the length.
if (arangeDescriptor.address || arangeDescriptor.length)
m_arange_descriptors.push_back(arangeDescriptor);
else
break; // We are done if we get a zero address and length
}
return !m_arange_descriptors.empty();
}
return false;
}
dw_offset_t
DWARFDebugArangeSet::GetOffsetOfNextEntry() const
{
return m_offset + m_header.length + 4;
}
void
DWARFDebugArangeSet::Dump(Stream *s) const
{
s->Printf("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
m_header.length ,m_header.version, m_header.cu_offset, m_header.addr_size, m_header.seg_size);
const uint32_t hex_width = m_header.addr_size * 2;
DescriptorConstIter pos;
DescriptorConstIter end = m_arange_descriptors.end();
for (pos = m_arange_descriptors.begin(); pos != end; ++pos)
s->Printf("[0x%*.*" PRIx64 " - 0x%*.*" PRIx64 ")\n",
hex_width, hex_width, pos->address,
hex_width, hex_width, pos->end_address());
}
class DescriptorContainsAddress
{
public:
DescriptorContainsAddress (dw_addr_t address) : m_address(address) {}
bool operator() (const DWARFDebugArangeSet::Descriptor& desc) const
{
return (m_address >= desc.address) && (m_address < (desc.address + desc.length));
}
private:
const dw_addr_t m_address;
};
dw_offset_t
DWARFDebugArangeSet::FindAddress(dw_addr_t address) const
{
DescriptorConstIter end = m_arange_descriptors.end();
DescriptorConstIter pos = std::find_if( m_arange_descriptors.begin(), end, // Range
DescriptorContainsAddress(address));// Predicate
if (pos != end)
return m_header.cu_offset;
return DW_INVALID_OFFSET;
}