1 //===-- DWARFCompileUnit.cpp ----------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 #include "DWARFCompileUnit.h"
11 #include "DWARFContext.h"
12 #include "DWARFFormValue.h"
13 #include "llvm/Support/Dwarf.h"
14 #include "llvm/Support/Format.h"
15 #include "llvm/Support/raw_ostream.h"
17 using namespace dwarf;
19 DataExtractor DWARFCompileUnit::getDebugInfoExtractor() const {
20 return DataExtractor(Context.getInfoSection(),
21 Context.isLittleEndian(), getAddressByteSize());
24 bool DWARFCompileUnit::extract(DataExtractor debug_info, uint32_t *offset_ptr) {
29 if (debug_info.isValidOffset(*offset_ptr)) {
31 const DWARFDebugAbbrev *abbr = Context.getDebugAbbrev();
32 Length = debug_info.getU32(offset_ptr);
33 Version = debug_info.getU16(offset_ptr);
34 abbrOffset = debug_info.getU32(offset_ptr);
35 AddrSize = debug_info.getU8(offset_ptr);
37 bool lengthOK = debug_info.isValidOffset(getNextCompileUnitOffset()-1);
38 bool versionOK = DWARFContext::isSupportedVersion(Version);
39 bool abbrOffsetOK = Context.getAbbrevSection().size() > abbrOffset;
40 bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
42 if (lengthOK && versionOK && addrSizeOK && abbrOffsetOK && abbr != NULL) {
43 Abbrevs = abbr->getAbbreviationDeclarationSet(abbrOffset);
47 // reset the offset to where we tried to parse from if anything went wrong
55 DWARFCompileUnit::extract(uint32_t offset, DataExtractor debug_info_data,
56 const DWARFAbbreviationDeclarationSet *abbrevs) {
61 if (debug_info_data.isValidOffset(offset)) {
62 Length = debug_info_data.getU32(&offset);
63 Version = debug_info_data.getU16(&offset);
64 bool abbrevsOK = debug_info_data.getU32(&offset) == abbrevs->getOffset();
66 AddrSize = debug_info_data.getU8 (&offset);
68 bool versionOK = DWARFContext::isSupportedVersion(Version);
69 bool addrSizeOK = AddrSize == 4 || AddrSize == 8;
71 if (versionOK && addrSizeOK && abbrevsOK &&
72 debug_info_data.isValidOffset(offset))
78 void DWARFCompileUnit::clear() {
88 void DWARFCompileUnit::dump(raw_ostream &OS) {
89 OS << format("0x%08x", Offset) << ": Compile Unit:"
90 << " length = " << format("0x%08x", Length)
91 << " version = " << format("0x%04x", Version)
92 << " abbr_offset = " << format("0x%04x", Abbrevs->getOffset())
93 << " addr_size = " << format("0x%02x", AddrSize)
94 << " (next CU at " << format("0x%08x", getNextCompileUnitOffset())
97 getCompileUnitDIE(false)->dump(OS, this, -1U);
100 void DWARFCompileUnit::setDIERelations() {
101 if (DieArray.empty())
103 DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
104 DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
105 DWARFDebugInfoEntryMinimal *curr_die;
106 // We purposely are skipping the last element in the array in the loop below
107 // so that we can always have a valid next item
108 for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
109 // Since our loop doesn't include the last element, we can always
110 // safely access the next die in the array.
111 DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
113 const DWARFAbbreviationDeclaration *curr_die_abbrev =
114 curr_die->getAbbreviationDeclarationPtr();
116 if (curr_die_abbrev) {
118 if (curr_die_abbrev->hasChildren())
119 next_die->setParent(curr_die);
121 curr_die->setSibling(next_die);
123 // NULL DIE that terminates a sibling chain
124 DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
126 parent->setSibling(next_die);
130 // Since we skipped the last element, we need to fix it up!
131 if (die_array_begin < die_array_end)
132 curr_die->setParent(die_array_begin);
135 size_t DWARFCompileUnit::extractDIEsIfNeeded(bool cu_die_only) {
136 const size_t initial_die_array_size = DieArray.size();
137 if ((cu_die_only && initial_die_array_size > 0) ||
138 initial_die_array_size > 1)
139 return 0; // Already parsed
141 // Set the offset to that of the first DIE and calculate the start of the
142 // next compilation unit header.
143 uint32_t offset = getFirstDIEOffset();
144 uint32_t next_cu_offset = getNextCompileUnitOffset();
146 DWARFDebugInfoEntryMinimal die;
147 // Keep a flat array of the DIE for binary lookup by DIE offset
149 // We are in our compile unit, parse starting at the offset
150 // we were told to parse
152 const uint8_t *fixed_form_sizes =
153 DWARFFormValue::getFixedFormSizesForAddressSize(getAddressByteSize());
155 while (offset < next_cu_offset &&
156 die.extractFast(this, fixed_form_sizes, &offset)) {
160 die.getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
161 if (base_addr == -1U)
162 base_addr = die.getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
163 setBaseAddress(base_addr);
170 else if (depth == 0 && initial_die_array_size == 1) {
171 // Don't append the CU die as we already did that
176 const DWARFAbbreviationDeclaration *abbrDecl =
177 die.getAbbreviationDeclarationPtr();
180 if (abbrDecl->hasChildren())
187 break; // We are done with this compile unit!
192 // Give a little bit of info if we encounter corrupt DWARF (our offset
193 // should always terminate at or before the start of the next compilation
195 if (offset > next_cu_offset) {
196 fprintf (stderr, "warning: DWARF compile unit extends beyond its bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), offset);
200 return DieArray.size();
203 void DWARFCompileUnit::clearDIEs(bool keep_compile_unit_die) {
204 if (DieArray.size() > 1) {
205 // std::vectors never get any smaller when resized to a smaller size,
206 // or when clear() or erase() are called, the size will report that it
207 // is smaller, but the memory allocated remains intact (call capacity()
208 // to see this). So we need to create a temporary vector and swap the
209 // contents which will cause just the internal pointers to be swapped
210 // so that when "tmp_array" goes out of scope, it will destroy the
213 // Save at least the compile unit DIE
214 std::vector<DWARFDebugInfoEntryMinimal> tmpArray;
215 DieArray.swap(tmpArray);
216 if (keep_compile_unit_die)
217 DieArray.push_back(tmpArray.front());
222 DWARFCompileUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
223 bool clear_dies_if_already_not_parsed){
224 // This function is usually called if there in no .debug_aranges section
225 // in order to produce a compile unit level set of address ranges that
226 // is accurate. If the DIEs weren't parsed, then we don't want all dies for
227 // all compile units to stay loaded when they weren't needed. So we can end
228 // up parsing the DWARF and then throwing them all away to keep memory usage
230 const bool clear_dies = extractDIEsIfNeeded(false) > 1;
232 DieArray[0].buildAddressRangeTable(this, debug_aranges);
234 // Keep memory down by clearing DIEs if this generate function
235 // caused them to be parsed.