DWARFDebugInfoEntry.cpp revision cd61455798777446f35723fdb77f54a17e602009 
1//===-- DWARFDebugInfoEntry.cpp -------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#include "DWARFDebugInfoEntry.h"
11#include "DWARFCompileUnit.h"
12#include "DWARFContext.h"
13#include "DWARFDebugAbbrev.h"
14#include "llvm/DebugInfo/DWARFFormValue.h"
15#include "llvm/Support/Debug.h"
16#include "llvm/Support/Dwarf.h"
17#include "llvm/Support/Format.h"
18#include "llvm/Support/raw_ostream.h"
19using namespace llvm;
20using namespace dwarf;
21
22void DWARFDebugInfoEntryMinimal::dump(raw_ostream &OS,
23                                      const DWARFCompileUnit *cu,
24                                      unsigned recurseDepth,
25                                      unsigned indent) const {
26  DataExtractor debug_info_data = cu->getDebugInfoExtractor();
27  uint32_t offset = Offset;
28
29  if (debug_info_data.isValidOffset(offset)) {
30    uint32_t abbrCode = debug_info_data.getULEB128(&offset);
31
32    OS << format("\n0x%8.8x: ", Offset);
33    if (abbrCode) {
34      if (AbbrevDecl) {
35        const char *tagString = TagString(getTag());
36        if (tagString)
37          OS.indent(indent) << tagString;
38        else
39          OS.indent(indent) << format("DW_TAG_Unknown_%x", getTag());
40        OS << format(" [%u] %c\n", abbrCode,
41                     AbbrevDecl->hasChildren() ? '*' : ' ');
42
43        // Dump all data in the DIE for the attributes.
44        const uint32_t numAttributes = AbbrevDecl->getNumAttributes();
45        for (uint32_t i = 0; i != numAttributes; ++i) {
46          uint16_t attr = AbbrevDecl->getAttrByIndex(i);
47          uint16_t form = AbbrevDecl->getFormByIndex(i);
48          dumpAttribute(OS, cu, &offset, attr, form, indent);
49        }
50
51        const DWARFDebugInfoEntryMinimal *child = getFirstChild();
52        if (recurseDepth > 0 && child) {
53          while (child) {
54            child->dump(OS, cu, recurseDepth-1, indent+2);
55            child = child->getSibling();
56          }
57        }
58      } else {
59        OS << "Abbreviation code not found in 'debug_abbrev' class for code: "
60           << abbrCode << '\n';
61      }
62    } else {
63      OS.indent(indent) << "NULL\n";
64    }
65  }
66}
67
68void DWARFDebugInfoEntryMinimal::dumpAttribute(raw_ostream &OS,
69                                               const DWARFCompileUnit *cu,
70                                               uint32_t* offset_ptr,
71                                               uint16_t attr,
72                                               uint16_t form,
73                                               unsigned indent) const {
74  OS << format("0x%8.8x: ", *offset_ptr);
75  OS.indent(indent+2);
76  const char *attrString = AttributeString(attr);
77  if (attrString)
78    OS << attrString;
79  else
80    OS << format("DW_AT_Unknown_%x", attr);
81  const char *formString = FormEncodingString(form);
82  if (formString)
83    OS << " [" << formString << ']';
84  else
85    OS << format(" [DW_FORM_Unknown_%x]", form);
86
87  DWARFFormValue formValue(form);
88
89  if (!formValue.extractValue(cu->getDebugInfoExtractor(), offset_ptr, cu))
90    return;
91
92  OS << "\t(";
93  formValue.dump(OS, cu);
94  OS << ")\n";
95}
96
97bool DWARFDebugInfoEntryMinimal::extractFast(const DWARFCompileUnit *CU,
98                                             const uint8_t *FixedFormSizes,
99                                             uint32_t *OffsetPtr) {
100  Offset = *OffsetPtr;
101  DataExtractor DebugInfoData = CU->getDebugInfoExtractor();
102  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
103  if (0 == AbbrCode) {
104    // NULL debug tag entry.
105    AbbrevDecl = NULL;
106    return true;
107  }
108  AbbrevDecl = CU->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
109  assert(AbbrevDecl);
110  assert(FixedFormSizes); // For best performance this should be specified!
111
112  // Skip all data in the .debug_info for the attributes
113  for (uint32_t i = 0, n = AbbrevDecl->getNumAttributes(); i < n; ++i) {
114    uint16_t Form = AbbrevDecl->getFormByIndex(i);
115
116    // FIXME: Currently we're checking if this is less than the last
117    // entry in the fixed_form_sizes table, but this should be changed
118    // to use dynamic dispatch.
119    uint8_t FixedFormSize =
120        (Form < DW_FORM_ref_sig8) ? FixedFormSizes[Form] : 0;
121    if (FixedFormSize)
122      *OffsetPtr += FixedFormSize;
123    else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr,
124                                        CU)) {
125      // Restore the original offset.
126      *OffsetPtr = Offset;
127      return false;
128    }
129  }
130  return true;
131}
132
133bool
134DWARFDebugInfoEntryMinimal::extract(const DWARFCompileUnit *CU,
135                                    uint32_t *OffsetPtr) {
136  DataExtractor DebugInfoData = CU->getDebugInfoExtractor();
137  const uint32_t CUEndOffset = CU->getNextCompileUnitOffset();
138  Offset = *OffsetPtr;
139  if ((Offset >= CUEndOffset) || !DebugInfoData.isValidOffset(Offset))
140    return false;
141  uint64_t AbbrCode = DebugInfoData.getULEB128(OffsetPtr);
142  if (0 == AbbrCode) {
143    // NULL debug tag entry.
144    AbbrevDecl = NULL;
145    return true;
146  }
147  AbbrevDecl = CU->getAbbreviations()->getAbbreviationDeclaration(AbbrCode);
148  if (0 == AbbrevDecl) {
149    // Restore the original offset.
150    *OffsetPtr = Offset;
151    return false;
152  }
153  bool IsCompileUnitTag = (AbbrevDecl->getTag() == DW_TAG_compile_unit);
154  if (IsCompileUnitTag)
155    const_cast<DWARFCompileUnit*>(CU)->setBaseAddress(0);
156
157  // Skip all data in the .debug_info for the attributes
158  for (uint32_t i = 0, n = AbbrevDecl->getNumAttributes(); i < n; ++i) {
159    uint16_t Attr = AbbrevDecl->getAttrByIndex(i);
160    uint16_t Form = AbbrevDecl->getFormByIndex(i);
161
162    if (IsCompileUnitTag &&
163        ((Attr == DW_AT_entry_pc) || (Attr == DW_AT_low_pc))) {
164      DWARFFormValue FormValue(Form);
165      if (FormValue.extractValue(DebugInfoData, OffsetPtr, CU)) {
166        if (Attr == DW_AT_low_pc || Attr == DW_AT_entry_pc)
167          const_cast<DWARFCompileUnit*>(CU)
168            ->setBaseAddress(FormValue.getUnsigned());
169      }
170    } else if (!DWARFFormValue::skipValue(Form, DebugInfoData, OffsetPtr,
171                                          CU)) {
172      // Restore the original offset.
173      *OffsetPtr = Offset;
174      return false;
175    }
176  }
177  return true;
178}
179
180bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
181  return getTag() == DW_TAG_subprogram;
182}
183
184bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
185  uint32_t Tag = getTag();
186  return Tag == DW_TAG_subprogram ||
187         Tag == DW_TAG_inlined_subroutine;
188}
189
190uint32_t
191DWARFDebugInfoEntryMinimal::getAttributeValue(const DWARFCompileUnit *cu,
192                                              const uint16_t attr,
193                                              DWARFFormValue &form_value,
194                                              uint32_t *end_attr_offset_ptr)
195                                              const {
196  if (AbbrevDecl) {
197    uint32_t attr_idx = AbbrevDecl->findAttributeIndex(attr);
198
199    if (attr_idx != -1U) {
200      uint32_t offset = getOffset();
201
202      DataExtractor debug_info_data = cu->getDebugInfoExtractor();
203
204      // Skip the abbreviation code so we are at the data for the attributes
205      debug_info_data.getULEB128(&offset);
206
207      uint32_t idx = 0;
208      while (idx < attr_idx)
209        DWARFFormValue::skipValue(AbbrevDecl->getFormByIndex(idx++),
210                                  debug_info_data, &offset, cu);
211
212      const uint32_t attr_offset = offset;
213      form_value = DWARFFormValue(AbbrevDecl->getFormByIndex(idx));
214      if (form_value.extractValue(debug_info_data, &offset, cu)) {
215        if (end_attr_offset_ptr)
216          *end_attr_offset_ptr = offset;
217        return attr_offset;
218      }
219    }
220  }
221
222  return 0;
223}
224
225const char*
226DWARFDebugInfoEntryMinimal::getAttributeValueAsString(
227                                                     const DWARFCompileUnit* cu,
228                                                     const uint16_t attr,
229                                                     const char* fail_value)
230                                                     const {
231  DWARFFormValue form_value;
232  if (getAttributeValue(cu, attr, form_value)) {
233    DataExtractor stringExtractor(cu->getStringSection(), false, 0);
234    return form_value.getAsCString(&stringExtractor);
235  }
236  return fail_value;
237}
238
239uint64_t
240DWARFDebugInfoEntryMinimal::getAttributeValueAsUnsigned(
241                                                    const DWARFCompileUnit* cu,
242                                                    const uint16_t attr,
243                                                    uint64_t fail_value) const {
244  DWARFFormValue form_value;
245  if (getAttributeValue(cu, attr, form_value))
246      return form_value.getUnsigned();
247  return fail_value;
248}
249
250int64_t
251DWARFDebugInfoEntryMinimal::getAttributeValueAsSigned(
252                                                     const DWARFCompileUnit* cu,
253                                                     const uint16_t attr,
254                                                     int64_t fail_value) const {
255  DWARFFormValue form_value;
256  if (getAttributeValue(cu, attr, form_value))
257      return form_value.getSigned();
258  return fail_value;
259}
260
261uint64_t
262DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
263                                                     const DWARFCompileUnit* cu,
264                                                     const uint16_t attr,
265                                                     uint64_t fail_value)
266                                                     const {
267  DWARFFormValue form_value;
268  if (getAttributeValue(cu, attr, form_value))
269      return form_value.getReference(cu);
270  return fail_value;
271}
272
273bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFCompileUnit *CU,
274                                                 uint64_t &LowPC,
275                                                 uint64_t &HighPC) const {
276  HighPC = -1ULL;
277  LowPC = getAttributeValueAsUnsigned(CU, DW_AT_low_pc, -1ULL);
278  if (LowPC != -1ULL)
279    HighPC = getAttributeValueAsUnsigned(CU, DW_AT_high_pc, -1ULL);
280  return (HighPC != -1ULL);
281}
282
283void
284DWARFDebugInfoEntryMinimal::buildAddressRangeTable(const DWARFCompileUnit *CU,
285                                               DWARFDebugAranges *DebugAranges)
286                                                   const {
287  if (AbbrevDecl) {
288    if (isSubprogramDIE()) {
289      uint64_t LowPC, HighPC;
290      if (getLowAndHighPC(CU, LowPC, HighPC)) {
291        DebugAranges->appendRange(CU->getOffset(), LowPC, HighPC);
292      }
293      // FIXME: try to append ranges from .debug_ranges section.
294    }
295
296    const DWARFDebugInfoEntryMinimal *child = getFirstChild();
297    while (child) {
298      child->buildAddressRangeTable(CU, DebugAranges);
299      child = child->getSibling();
300    }
301  }
302}
303
304bool
305DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
306                                                     const DWARFCompileUnit *CU,
307                                                     const uint64_t Address)
308                                                     const {
309  if (isNULL())
310    return false;
311  uint64_t LowPC, HighPC;
312  if (getLowAndHighPC(CU, LowPC, HighPC))
313    return (LowPC <= Address && Address <= HighPC);
314  // Try to get address ranges from .debug_ranges section.
315  uint32_t RangesOffset = getAttributeValueAsReference(CU, DW_AT_ranges, -1U);
316  if (RangesOffset != -1U) {
317    DWARFDebugRangeList RangeList;
318    if (CU->extractRangeList(RangesOffset, RangeList))
319      return RangeList.containsAddress(CU->getBaseAddress(), Address);
320  }
321  return false;
322}
323
324const char*
325DWARFDebugInfoEntryMinimal::getSubroutineName(const DWARFCompileUnit *CU)
326                                                                         const {
327  if (!isSubroutineDIE())
328    return 0;
329  // Try to get mangled name if possible.
330  if (const char *name =
331      getAttributeValueAsString(CU, DW_AT_MIPS_linkage_name, 0))
332    return name;
333  if (const char *name = getAttributeValueAsString(CU, DW_AT_linkage_name, 0))
334    return name;
335  if (const char *name = getAttributeValueAsString(CU, DW_AT_name, 0))
336    return name;
337  // Try to get name from specification DIE.
338  uint32_t spec_ref =
339      getAttributeValueAsReference(CU, DW_AT_specification, -1U);
340  if (spec_ref != -1U) {
341    DWARFDebugInfoEntryMinimal spec_die;
342    if (spec_die.extract(CU, &spec_ref)) {
343      if (const char *name = spec_die.getSubroutineName(CU))
344        return name;
345    }
346  }
347  // Try to get name from abstract origin DIE.
348  uint32_t abs_origin_ref =
349      getAttributeValueAsReference(CU, DW_AT_abstract_origin, -1U);
350  if (abs_origin_ref != -1U) {
351    DWARFDebugInfoEntryMinimal abs_origin_die;
352    if (abs_origin_die.extract(CU, &abs_origin_ref)) {
353      if (const char *name = abs_origin_die.getSubroutineName(CU))
354        return name;
355    }
356  }
357  return 0;
358}
359
360void DWARFDebugInfoEntryMinimal::getCallerFrame(const DWARFCompileUnit *CU,
361                                                uint32_t &CallFile,
362                                                uint32_t &CallLine,
363                                                uint32_t &CallColumn) const {
364  CallFile = getAttributeValueAsUnsigned(CU, DW_AT_call_file, 0);
365  CallLine = getAttributeValueAsUnsigned(CU, DW_AT_call_line, 0);
366  CallColumn = getAttributeValueAsUnsigned(CU, DW_AT_call_column, 0);
367}
368
369DWARFDebugInfoEntryMinimal::InlinedChain
370DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
371                                                     const DWARFCompileUnit *CU,
372                                                     const uint64_t Address)
373                                                     const {
374  DWARFDebugInfoEntryMinimal::InlinedChain InlinedChain;
375  if (isNULL())
376    return InlinedChain;
377  for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
378    // Append current DIE to inlined chain only if it has correct tag
379    // (e.g. it is not a lexical block).
380    if (DIE->isSubroutineDIE()) {
381      InlinedChain.push_back(*DIE);
382    }
383    // Try to get child which also contains provided address.
384    const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
385    while (Child) {
386      if (Child->addressRangeContainsAddress(CU, Address)) {
387        // Assume there is only one such child.
388        break;
389      }
390      Child = Child->getSibling();
391    }
392    DIE = Child;
393  }
394  // Reverse the obtained chain to make the root of inlined chain last.
395  std::reverse(InlinedChain.begin(), InlinedChain.end());
396  return InlinedChain;
397}
398