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//===-- DWARFDebugArangeSet.cpp -------------------------------------------===//
//
// 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 "llvm/Support/Format.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
using namespace llvm;
void DWARFDebugArangeSet::clear() {
Offset = -1U;
std::memset(&Header, 0, sizeof(Header));
ArangeDescriptors.clear();
}
void DWARFDebugArangeSet::compact() {
if (ArangeDescriptors.empty())
return;
// Iterate through all arange descriptors and combine any ranges that
// overlap or have matching boundaries. The ArangeDescriptors are assumed
// to be in ascending order.
uint32_t i = 0;
while (i + 1 < ArangeDescriptors.size()) {
if (ArangeDescriptors[i].getEndAddress() >= ArangeDescriptors[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 uint64_t max_end_addr =
std::max(ArangeDescriptors[i].getEndAddress(),
ArangeDescriptors[i+1].getEndAddress());
ArangeDescriptors[i].Length = max_end_addr - ArangeDescriptors[i].Address;
// Now remove the next entry as it was just combined with the previous one
ArangeDescriptors.erase(ArangeDescriptors.begin()+i+1);
} else {
// Discontiguous address range, just proceed to the next one.
++i;
}
}
}
bool
DWARFDebugArangeSet::extract(DataExtractor data, uint32_t *offset_ptr) {
if (data.isValidOffset(*offset_ptr)) {
ArangeDescriptors.clear();
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.
Header.Length = data.getU32(offset_ptr);
Header.Version = data.getU16(offset_ptr);
Header.CuOffset = data.getU32(offset_ptr);
Header.AddrSize = data.getU8(offset_ptr);
Header.SegSize = data.getU8(offset_ptr);
// Perform basic validation of the header fields.
if (!data.isValidOffsetForDataOfSize(Offset, Header.Length) ||
(Header.AddrSize != 4 && Header.AddrSize != 8)) {
clear();
return false;
}
// 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 - Offset;
const uint32_t tuple_size = Header.AddrSize * 2;
uint32_t first_tuple_offset = 0;
while (first_tuple_offset < header_size)
first_tuple_offset += tuple_size;
*offset_ptr = Offset + first_tuple_offset;
Descriptor arangeDescriptor;
assert(sizeof(arangeDescriptor.Address) == sizeof(arangeDescriptor.Length));
assert(sizeof(arangeDescriptor.Address) >= Header.AddrSize);
while (data.isValidOffset(*offset_ptr)) {
arangeDescriptor.Address = data.getUnsigned(offset_ptr, Header.AddrSize);
arangeDescriptor.Length = data.getUnsigned(offset_ptr, Header.AddrSize);
// Each set of tuples is terminated by a 0 for the address and 0
// for the length.
if (arangeDescriptor.Address || arangeDescriptor.Length)
ArangeDescriptors.push_back(arangeDescriptor);
else
break; // We are done if we get a zero address and length
}
return !ArangeDescriptors.empty();
}
return false;
}
void DWARFDebugArangeSet::dump(raw_ostream &OS) const {
OS << format("Address Range Header: length = 0x%8.8x, version = 0x%4.4x, ",
Header.Length, Header.Version)
<< format("cu_offset = 0x%8.8x, addr_size = 0x%2.2x, seg_size = 0x%2.2x\n",
Header.CuOffset, Header.AddrSize, Header.SegSize);
const uint32_t hex_width = Header.AddrSize * 2;
for (DescriptorConstIter pos = ArangeDescriptors.begin(),
end = ArangeDescriptors.end(); pos != end; ++pos)
OS << format("[0x%*.*" PRIx64 " -", hex_width, hex_width, pos->Address)
<< format(" 0x%*.*" PRIx64 ")\n",
hex_width, hex_width, pos->getEndAddress());
}
namespace {
class DescriptorContainsAddress {
const uint64_t Address;
public:
DescriptorContainsAddress(uint64_t address) : Address(address) {}
bool operator()(const DWARFDebugArangeSet::Descriptor &desc) const {
return Address >= desc.Address && Address < (desc.Address + desc.Length);
}
};
}
uint32_t DWARFDebugArangeSet::findAddress(uint64_t address) const {
DescriptorConstIter end = ArangeDescriptors.end();
DescriptorConstIter pos =
std::find_if(ArangeDescriptors.begin(), end, // Range
DescriptorContainsAddress(address)); // Predicate
if (pos != end)
return Header.CuOffset;
return -1U;
}