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 extractDIEsIfNeeded(false);
98 DieArray[0].dump(OS, this, -1U);
101 void DWARFCompileUnit::setDIERelations() {
102 if (DieArray.empty())
104 DWARFDebugInfoEntryMinimal *die_array_begin = &DieArray.front();
105 DWARFDebugInfoEntryMinimal *die_array_end = &DieArray.back();
106 DWARFDebugInfoEntryMinimal *curr_die;
107 // We purposely are skipping the last element in the array in the loop below
108 // so that we can always have a valid next item
109 for (curr_die = die_array_begin; curr_die < die_array_end; ++curr_die) {
110 // Since our loop doesn't include the last element, we can always
111 // safely access the next die in the array.
112 DWARFDebugInfoEntryMinimal *next_die = curr_die + 1;
114 const DWARFAbbreviationDeclaration *curr_die_abbrev =
115 curr_die->getAbbreviationDeclarationPtr();
117 if (curr_die_abbrev) {
119 if (curr_die_abbrev->hasChildren())
120 next_die->setParent(curr_die);
122 curr_die->setSibling(next_die);
124 // NULL DIE that terminates a sibling chain
125 DWARFDebugInfoEntryMinimal *parent = curr_die->getParent();
127 parent->setSibling(next_die);
131 // Since we skipped the last element, we need to fix it up!
132 if (die_array_begin < die_array_end)
133 curr_die->setParent(die_array_begin);
136 size_t DWARFCompileUnit::extractDIEsIfNeeded(bool cu_die_only) {
137 const size_t initial_die_array_size = DieArray.size();
138 if ((cu_die_only && initial_die_array_size > 0) ||
139 initial_die_array_size > 1)
140 return 0; // Already parsed
142 // Set the offset to that of the first DIE and calculate the start of the
143 // next compilation unit header.
144 uint32_t offset = getFirstDIEOffset();
145 uint32_t next_cu_offset = getNextCompileUnitOffset();
147 DWARFDebugInfoEntryMinimal die;
148 // Keep a flat array of the DIE for binary lookup by DIE offset
150 // We are in our compile unit, parse starting at the offset
151 // we were told to parse
153 const uint8_t *fixed_form_sizes =
154 DWARFFormValue::getFixedFormSizesForAddressSize(getAddressByteSize());
156 while (offset < next_cu_offset &&
157 die.extractFast(this, fixed_form_sizes, &offset)) {
161 die.getAttributeValueAsUnsigned(this, DW_AT_low_pc, -1U);
162 if (base_addr == -1U)
163 base_addr = die.getAttributeValueAsUnsigned(this, DW_AT_entry_pc, 0);
164 setBaseAddress(base_addr);
171 else if (depth == 0 && initial_die_array_size == 1) {
172 // Don't append the CU die as we already did that
177 const DWARFAbbreviationDeclaration *abbrDecl =
178 die.getAbbreviationDeclarationPtr();
181 if (abbrDecl->hasChildren())
188 break; // We are done with this compile unit!
193 // Give a little bit of info if we encounter corrupt DWARF (our offset
194 // should always terminate at or before the start of the next compilation
196 if (offset > next_cu_offset) {
197 fprintf (stderr, "warning: DWARF compile unit extends beyond its bounds cu 0x%8.8x at 0x%8.8x'\n", getOffset(), offset);
201 return DieArray.size();
204 void DWARFCompileUnit::clearDIEs(bool keep_compile_unit_die) {
205 if (DieArray.size() > 1) {
206 // std::vectors never get any smaller when resized to a smaller size,
207 // or when clear() or erase() are called, the size will report that it
208 // is smaller, but the memory allocated remains intact (call capacity()
209 // to see this). So we need to create a temporary vector and swap the
210 // contents which will cause just the internal pointers to be swapped
211 // so that when "tmp_array" goes out of scope, it will destroy the
214 // Save at least the compile unit DIE
215 std::vector<DWARFDebugInfoEntryMinimal> tmpArray;
216 DieArray.swap(tmpArray);
217 if (keep_compile_unit_die)
218 DieArray.push_back(tmpArray.front());
223 DWARFCompileUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
224 bool clear_dies_if_already_not_parsed){
225 // This function is usually called if there in no .debug_aranges section
226 // in order to produce a compile unit level set of address ranges that
227 // is accurate. If the DIEs weren't parsed, then we don't want all dies for
228 // all compile units to stay loaded when they weren't needed. So we can end
229 // up parsing the DWARF and then throwing them all away to keep memory usage
231 const bool clear_dies = extractDIEsIfNeeded(false) > 1;
233 DieArray[0].buildAddressRangeTable(this, debug_aranges);
235 // Keep memory down by clearing DIEs if this generate function
236 // caused them to be parsed.