Add support for fetching inlining context (stack of source code locations)

by instruction address from DWARF.

Add --inlining flag to llvm-dwarfdump to demonstrate and test this functionality,
so that "llvm-dwarfdump --inlining --address=0x..." now works much like
"addr2line -i 0x...", provided that the binary has debug info
(Clang's -gline-tables-only *is* enough).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163128 91177308-0d34-0410-b5e6-96231b3b80d8

8 files changed, 279 insertions, 79 deletions

diff --git a/lib/DebugInfo/DWARFCompileUnit.cpp b/lib/DebugInfo/DWARFCompileUnit.cpp
index d32fd6dd7e..bdd65b77e4 100644
--- a/lib/DebugInfo/DWARFCompileUnit.cpp
+++ b/lib/DebugInfo/DWARFCompileUnit.cpp
@@ -75,6 +75,15 @@ DWARFCompileUnit::extract(uint32_t offset, DataExtractor debug_info_data,
   return 0;
 }
 
+bool DWARFCompileUnit::extractRangeList(uint32_t RangeListOffset,
+                                        DWARFDebugRangeList &RangeList) const {
+  // Require that compile unit is extracted.
+  assert(DieArray.size() > 0);
+  DataExtractor RangesData(Context.getRangeSection(),
+                           Context.isLittleEndian(), AddrSize);
+  return RangeList.extract(RangesData, &RangeListOffset);
+}
+
 void DWARFCompileUnit::clear() {
   Offset = 0;
   Length = 0;
@@ -246,12 +255,21 @@ DWARFCompileUnit::buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
     clearDIEs(true);
 }
 
-const DWARFDebugInfoEntryMinimal*
-DWARFCompileUnit::getFunctionDIEForAddress(int64_t address) {
+DWARFDebugInfoEntryMinimal::InlinedChain
+DWARFCompileUnit::getInlinedChainForAddress(uint64_t Address) {
+  // First, find a subprogram that contains the given address (the root
+  // of inlined chain).
   extractDIEsIfNeeded(false);
+  const DWARFDebugInfoEntryMinimal *SubprogramDIE = 0;
   for (size_t i = 0, n = DieArray.size(); i != n; i++) {
-    if (DieArray[i].addressRangeContainsAddress(this, address))
-      return &DieArray[i];
+    if (DieArray[i].isSubprogramDIE() &&
+        DieArray[i].addressRangeContainsAddress(this, Address)) {
+      SubprogramDIE = &DieArray[i];
+      break;
+    }
   }
-  return 0;
+  // Get inlined chain rooted at this subprogram DIE.
+  if (!SubprogramDIE)
+    return DWARFDebugInfoEntryMinimal::InlinedChain();
+  return SubprogramDIE->getInlinedChainForAddress(this, Address);
 }
diff --git a/lib/DebugInfo/DWARFCompileUnit.h b/lib/DebugInfo/DWARFCompileUnit.h
index b34a5965af..03e28620d4 100644
--- a/lib/DebugInfo/DWARFCompileUnit.h
+++ b/lib/DebugInfo/DWARFCompileUnit.h
@@ -12,6 +12,7 @@
 
 #include "DWARFDebugAbbrev.h"
 #include "DWARFDebugInfoEntry.h"
+#include "DWARFDebugRangeList.h"
 #include <vector>
 
 namespace llvm {
@@ -45,6 +46,11 @@ public:
   /// extractDIEsIfNeeded - Parses a compile unit and indexes its DIEs if it
   /// hasn't already been done. Returns the number of DIEs parsed at this call.
   size_t extractDIEsIfNeeded(bool cu_die_only);
+  /// extractRangeList - extracts the range list referenced by this compile
+  /// unit from .debug_ranges section. Returns true on success.
+  /// Requires that compile unit is already extracted.
+  bool extractRangeList(uint32_t RangeListOffset,
+                        DWARFDebugRangeList &RangeList) const;
   void clear();
   void dump(raw_ostream &OS);
   uint32_t getOffset() const { return Offset; }
@@ -106,11 +112,11 @@ public:
 
   void buildAddressRangeTable(DWARFDebugAranges *debug_aranges,
                               bool clear_dies_if_already_not_parsed);
-  /// getFunctionDIEForAddress - Returns pointer to parsed subprogram DIE,
-  /// address ranges of which contain the provided address,
-  /// or NULL if there is no such subprogram. The pointer
-  /// is valid until DWARFCompileUnit::clear() or clearDIEs() is called.
-  const DWARFDebugInfoEntryMinimal *getFunctionDIEForAddress(int64_t address);
+
+  /// getInlinedChainForAddress - fetches inlined chain for a given address.
+  /// Returns empty chain if there is no subprogram containing address.
+  DWARFDebugInfoEntryMinimal::InlinedChain getInlinedChainForAddress(
+      uint64_t Address);
 };
 
 }
diff --git a/lib/DebugInfo/DWARFContext.cpp b/lib/DebugInfo/DWARFContext.cpp
index 3f9edd305b..241f55eaed 100644
--- a/lib/DebugInfo/DWARFContext.cpp
+++ b/lib/DebugInfo/DWARFContext.cpp
@@ -183,15 +183,11 @@ static bool getFileNameForCompileUnit(
   return true;
 }
 
-bool
-DWARFContext::getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
-                                            uint64_t Address,
-                                            bool NeedsAbsoluteFilePath,
-                                            std::string &FileName,
-                                            uint32_t &Line, uint32_t &Column) {
-  // Get the line table for this compile unit.
-  const DWARFDebugLine::LineTable *LineTable = getLineTableForCompileUnit(CU);
-  if (!LineTable)
+static bool getFileLineInfoForCompileUnit(
+    DWARFCompileUnit *CU, const DWARFDebugLine::LineTable *LineTable,
+    uint64_t Address, bool NeedsAbsoluteFilePath, std::string &FileName,
+    uint32_t &Line, uint32_t &Column) {
+  if (CU == 0 || LineTable == 0)
     return false;
   // Get the index of row we're looking for in the line table.
   uint32_t RowIndex = LineTable->lookupAddress(Address);
@@ -217,21 +213,84 @@ DILineInfo DWARFContext::getLineInfoForAddress(uint64_t Address,
   uint32_t Line = 0;
   uint32_t Column = 0;
   if (Specifier.needs(DILineInfoSpecifier::FunctionName)) {
-    const DWARFDebugInfoEntryMinimal *FunctionDIE =
-        CU->getFunctionDIEForAddress(Address);
-    if (FunctionDIE) {
-      if (const char *Name = FunctionDIE->getSubprogramName(CU))
+    // The address may correspond to instruction in some inlined function,
+    // so we have to build the chain of inlined functions and take the
+    // name of the topmost function in it.
+    const DWARFDebugInfoEntryMinimal::InlinedChain &InlinedChain =
+        CU->getInlinedChainForAddress(Address);
+    if (InlinedChain.size() > 0) {
+      const DWARFDebugInfoEntryMinimal &TopFunctionDIE = InlinedChain[0];
+      if (const char *Name = TopFunctionDIE.getSubroutineName(CU))
         FunctionName = Name;
     }
   }
   if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
+    const DWARFDebugLine::LineTable *LineTable =
+        getLineTableForCompileUnit(CU);
     const bool NeedsAbsoluteFilePath =
         Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
-    getFileLineInfoForCompileUnit(CU, Address, NeedsAbsoluteFilePath,
+    getFileLineInfoForCompileUnit(CU, LineTable, Address,
+                                  NeedsAbsoluteFilePath,
                                   FileName, Line, Column);
   }
   return DILineInfo(StringRef(FileName), StringRef(FunctionName),
                     Line, Column);
 }
 
+DIInliningInfo DWARFContext::getInliningInfoForAddress(uint64_t Address,
+    DILineInfoSpecifier Specifier) {
+  DWARFCompileUnit *CU = getCompileUnitForAddress(Address);
+  if (!CU)
+    return DIInliningInfo();
+
+  const DWARFDebugInfoEntryMinimal::InlinedChain &InlinedChain =
+      CU->getInlinedChainForAddress(Address);
+  if (InlinedChain.size() == 0)
+    return DIInliningInfo();
+
+  DIInliningInfo InliningInfo;
+  uint32_t CallFile = 0, CallLine = 0, CallColumn = 0;
+  const DWARFDebugLine::LineTable *LineTable = 0;
+  for (uint32_t i = 0, n = InlinedChain.size(); i != n; i++) {
+    const DWARFDebugInfoEntryMinimal &FunctionDIE = InlinedChain[i];
+    std::string FileName = "<invalid>";
+    std::string FunctionName = "<invalid>";
+    uint32_t Line = 0;
+    uint32_t Column = 0;
+    // Get function name if necessary.
+    if (Specifier.needs(DILineInfoSpecifier::FunctionName)) {
+      if (const char *Name = FunctionDIE.getSubroutineName(CU))
+        FunctionName = Name;
+    }
+    if (Specifier.needs(DILineInfoSpecifier::FileLineInfo)) {
+      const bool NeedsAbsoluteFilePath =
+          Specifier.needs(DILineInfoSpecifier::AbsoluteFilePath);
+      if (i == 0) {
+        // For the topmost frame, initialize the line table of this
+        // compile unit and fetch file/line info from it.
+        LineTable = getLineTableForCompileUnit(CU);
+        // For the topmost routine, get file/line info from line table.
+        getFileLineInfoForCompileUnit(CU, LineTable, Address,
+                                      NeedsAbsoluteFilePath,
+                                      FileName, Line, Column);
+      } else {
+        // Otherwise, use call file, call line and call column from
+        // previous DIE in inlined chain.
+        getFileNameForCompileUnit(CU, LineTable, CallFile,
+                                  NeedsAbsoluteFilePath, FileName);
+        Line = CallLine;
+        Column = CallColumn;
+      }
+      // Get call file/line/column of a current DIE.
+      if (i + 1 < n) {
+        FunctionDIE.getCallerFrame(CU, CallFile, CallLine, CallColumn);
+      }
+    }
+    DILineInfo Frame(StringRef(FileName), StringRef(FunctionName),
+                     Line, Column);
+    InliningInfo.addFrame(Frame);
+  }
+  return InliningInfo;
+}
+
 void DWARFContextInMemory::anchor() { }
diff --git a/lib/DebugInfo/DWARFContext.h b/lib/DebugInfo/DWARFContext.h
index ff343de716..76339979dd 100644
--- a/lib/DebugInfo/DWARFContext.h
+++ b/lib/DebugInfo/DWARFContext.h
@@ -66,6 +66,8 @@ public:
 
   virtual DILineInfo getLineInfoForAddress(uint64_t Address,
       DILineInfoSpecifier Specifier = DILineInfoSpecifier());
+  virtual DIInliningInfo getInliningInfoForAddress(uint64_t Address,
+      DILineInfoSpecifier Specifier = DILineInfoSpecifier());
 
   bool isLittleEndian() const { return IsLittleEndian; }
 
@@ -86,14 +88,6 @@ private:
   /// Return the compile unit which contains instruction with provided
   /// address.
   DWARFCompileUnit *getCompileUnitForAddress(uint64_t Address);
-
-  /// Fetches filename, line and column number for given address and
-  /// compile unit. Returns true on success.
-  bool getFileLineInfoForCompileUnit(DWARFCompileUnit *CU,
-                                     uint64_t Address,
-                                     bool NeedsAbsoluteFilePath,
-                                     std::string &FileName,
-                                     uint32_t &Line, uint32_t &Column);
 };
 
 /// DWARFContextInMemory is the simplest possible implementation of a
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.cpp b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
index b5a4f9450a..1bfd126a12 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.cpp
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.cpp
@@ -364,6 +364,16 @@ DWARFDebugInfoEntryMinimal::extract(const DWARFCompileUnit *cu,
   return false;
 }
 
+bool DWARFDebugInfoEntryMinimal::isSubprogramDIE() const {
+  return getTag() == DW_TAG_subprogram;
+}
+
+bool DWARFDebugInfoEntryMinimal::isSubroutineDIE() const {
+  uint32_t Tag = getTag();
+  return Tag == DW_TAG_subprogram ||
+         Tag == DW_TAG_inlined_subroutine;
+}
+
 uint32_t
 DWARFDebugInfoEntryMinimal::getAttributeValue(const DWARFCompileUnit *cu,
                                               const uint16_t attr,
@@ -446,24 +456,31 @@ DWARFDebugInfoEntryMinimal::getAttributeValueAsReference(
   return fail_value;
 }
 
+bool DWARFDebugInfoEntryMinimal::getLowAndHighPC(const DWARFCompileUnit *CU,
+    uint64_t &LowPC, uint64_t &HighPC) const {
+  HighPC = -1ULL;
+  LowPC = getAttributeValueAsUnsigned(CU, DW_AT_low_pc, -1ULL);
+  if (LowPC != -1ULL)
+    HighPC = getAttributeValueAsUnsigned(CU, DW_AT_high_pc, -1ULL);
+  return (HighPC != -1ULL);
+}
+
 void
-DWARFDebugInfoEntryMinimal::buildAddressRangeTable(const DWARFCompileUnit *cu,
-                                               DWARFDebugAranges *debug_aranges)
+DWARFDebugInfoEntryMinimal::buildAddressRangeTable(const DWARFCompileUnit *CU,
+                                               DWARFDebugAranges *DebugAranges)
                                                    const {
   if (AbbrevDecl) {
-    uint16_t tag = AbbrevDecl->getTag();
-    if (tag == DW_TAG_subprogram) {
-      uint64_t hi_pc = -1ULL;
-      uint64_t lo_pc = getAttributeValueAsUnsigned(cu, DW_AT_low_pc, -1ULL);
-      if (lo_pc != -1ULL)
-        hi_pc = getAttributeValueAsUnsigned(cu, DW_AT_high_pc, -1ULL);
-      if (hi_pc != -1ULL)
-        debug_aranges->appendRange(cu->getOffset(), lo_pc, hi_pc);
+    if (isSubprogramDIE()) {
+      uint64_t LowPC, HighPC;
+      if (getLowAndHighPC(CU, LowPC, HighPC)) {
+        DebugAranges->appendRange(CU->getOffset(), LowPC, HighPC);
+      }
+      // FIXME: try to append ranges from .debug_ranges section.
     }
 
     const DWARFDebugInfoEntryMinimal *child = getFirstChild();
     while (child) {
-      child->buildAddressRangeTable(cu, debug_aranges);
+      child->buildAddressRangeTable(CU, DebugAranges);
       child = child->getSibling();
     }
   }
@@ -471,51 +488,90 @@ DWARFDebugInfoEntryMinimal::buildAddressRangeTable(const DWARFCompileUnit *cu,
 
 bool
 DWARFDebugInfoEntryMinimal::addressRangeContainsAddress(
-    const DWARFCompileUnit *cu, const uint64_t address) const {
-  if (!isNULL() && getTag() == DW_TAG_subprogram) {
-    uint64_t hi_pc = -1ULL;
-    uint64_t lo_pc = getAttributeValueAsUnsigned(cu, DW_AT_low_pc, -1ULL);
-    if (lo_pc != -1ULL)
-      hi_pc = getAttributeValueAsUnsigned(cu, DW_AT_high_pc, -1ULL);
-    if (hi_pc != -1ULL) {
-      return (lo_pc <= address && address < hi_pc);
-    }
+    const DWARFCompileUnit *CU, const uint64_t Address) const {
+  if (isNULL())
+    return false;
+  uint64_t LowPC, HighPC;
+  if (getLowAndHighPC(CU, LowPC, HighPC))
+    return (LowPC <= Address && Address <= HighPC);
+  // Try to get address ranges from .debug_ranges section.
+  uint32_t RangesOffset = getAttributeValueAsReference(CU, DW_AT_ranges, -1U);
+  if (RangesOffset != -1U) {
+    DWARFDebugRangeList RangeList;
+    if (CU->extractRangeList(RangesOffset, RangeList))
+      return RangeList.containsAddress(CU->getBaseAddress(), Address);
   }
   return false;
 }
 
 const char*
-DWARFDebugInfoEntryMinimal::getSubprogramName(
-    const DWARFCompileUnit *cu) const {
-  if (isNULL() || getTag() != DW_TAG_subprogram)
+DWARFDebugInfoEntryMinimal::getSubroutineName(
+    const DWARFCompileUnit *CU) const {
+  if (!isSubroutineDIE())
     return 0;
   // Try to get mangled name if possible.
   if (const char *name =
-      getAttributeValueAsString(cu, DW_AT_MIPS_linkage_name, 0))
+      getAttributeValueAsString(CU, DW_AT_MIPS_linkage_name, 0))
     return name;
-  if (const char *name = getAttributeValueAsString(cu, DW_AT_linkage_name, 0))
+  if (const char *name = getAttributeValueAsString(CU, DW_AT_linkage_name, 0))
     return name;
-  if (const char *name = getAttributeValueAsString(cu, DW_AT_name, 0))
+  if (const char *name = getAttributeValueAsString(CU, DW_AT_name, 0))
     return name;
   // Try to get name from specification DIE.
   uint32_t spec_ref =
-      getAttributeValueAsReference(cu, DW_AT_specification, -1U);
+      getAttributeValueAsReference(CU, DW_AT_specification, -1U);
   if (spec_ref != -1U) {
     DWARFDebugInfoEntryMinimal spec_die;
-    if (spec_die.extract(cu, &spec_ref)) {
-      if (const char *name = spec_die.getSubprogramName(cu))
+    if (spec_die.extract(CU, &spec_ref)) {
+      if (const char *name = spec_die.getSubroutineName(CU))
         return name;
     }
   }
   // Try to get name from abstract origin DIE.
   uint32_t abs_origin_ref =
-      getAttributeValueAsReference(cu, DW_AT_abstract_origin, -1U);
+      getAttributeValueAsReference(CU, DW_AT_abstract_origin, -1U);
   if (abs_origin_ref != -1U) {
     DWARFDebugInfoEntryMinimal abs_origin_die;
-    if (abs_origin_die.extract(cu, &abs_origin_ref)) {
-      if (const char *name = abs_origin_die.getSubprogramName(cu))
+    if (abs_origin_die.extract(CU, &abs_origin_ref)) {
+      if (const char *name = abs_origin_die.getSubroutineName(CU))
         return name;
     }
   }
   return 0;
 }
+
+void DWARFDebugInfoEntryMinimal::getCallerFrame(
+    const DWARFCompileUnit *CU, uint32_t &CallFile, uint32_t &CallLine,
+    uint32_t &CallColumn) const {
+  CallFile = getAttributeValueAsUnsigned(CU, DW_AT_call_file, 0);
+  CallLine = getAttributeValueAsUnsigned(CU, DW_AT_call_line, 0);
+  CallColumn = getAttributeValueAsUnsigned(CU, DW_AT_call_column, 0);
+}
+
+DWARFDebugInfoEntryMinimal::InlinedChain
+DWARFDebugInfoEntryMinimal::getInlinedChainForAddress(
+    const DWARFCompileUnit *CU, const uint64_t Address) const {
+  DWARFDebugInfoEntryMinimal::InlinedChain InlinedChain;
+  if (isNULL())
+    return InlinedChain;
+  for (const DWARFDebugInfoEntryMinimal *DIE = this; DIE; ) {
+    // Append current DIE to inlined chain only if it has correct tag
+    // (e.g. it is not a lexical block).
+    if (DIE->isSubroutineDIE()) {
+      InlinedChain.push_back(*DIE);
+    }
+    // Try to get child which also contains provided address.
+    const DWARFDebugInfoEntryMinimal *Child = DIE->getFirstChild();
+    while (Child) {
+      if (Child->addressRangeContainsAddress(CU, Address)) {
+        // Assume there is only one such child.
+        break;
+      }
+      Child = Child->getSibling();
+    }
+    DIE = Child;
+  }
+  // Reverse the obtained chain to make the root of inlined chain last.
+  std::reverse(InlinedChain.begin(), InlinedChain.end());
+  return InlinedChain;
+}
diff --git a/lib/DebugInfo/DWARFDebugInfoEntry.h b/lib/DebugInfo/DWARFDebugInfoEntry.h
index d5d86b9ec0..9c1b2be0a7 100644
--- a/lib/DebugInfo/DWARFDebugInfoEntry.h
+++ b/lib/DebugInfo/DWARFDebugInfoEntry.h
@@ -11,6 +11,7 @@
 #define LLVM_DEBUGINFO_DWARFDEBUGINFOENTRY_H
 
 #include "DWARFAbbreviationDeclaration.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/Support/DataTypes.h"
 
 namespace llvm {
@@ -19,6 +20,7 @@ class DWARFDebugAranges;
 class DWARFCompileUnit;
 class DWARFContext;
 class DWARFFormValue;
+class DWARFInlinedSubroutineChain;
 
 /// DWARFDebugInfoEntryMinimal - A DIE with only the minimum required data.
 class DWARFDebugInfoEntryMinimal {
@@ -52,6 +54,13 @@ public:
 
   uint32_t getTag() const { return AbbrevDecl ? AbbrevDecl->getTag() : 0; }
   bool isNULL() const { return AbbrevDecl == 0; }
+
+  /// Returns true if DIE represents a subprogram (not inlined).
+  bool isSubprogramDIE() const;
+  /// Returns true if DIE represents a subprogram or an inlined
+  /// subroutine.
+  bool isSubroutineDIE() const;
+
   uint32_t getOffset() const { return Offset; }
   uint32_t getNumAttributes() const {
     return !isNULL() ? AbbrevDecl->getNumAttributes() : 0;
@@ -126,17 +135,40 @@ public:
                                     const uint16_t attr,
                                     int64_t fail_value) const;
 
-  void buildAddressRangeTable(const DWARFCompileUnit *cu,
-                              DWARFDebugAranges *debug_aranges) const;
-
-  bool addressRangeContainsAddress(const DWARFCompileUnit *cu,
-                                   const uint64_t address) const;
-
-  // If a DIE represents a subprogram, returns its mangled name
-  // (or short name, if mangled is missing). This name may be fetched
-  // from specification or abstract origin for this subprogram.
-  // Returns null if no name is found.
-  const char* getSubprogramName(const DWARFCompileUnit *cu) const;
+  /// Retrieves DW_AT_low_pc and DW_AT_high_pc from CU.
+  /// Returns true if both attributes are present.
+  bool getLowAndHighPC(const DWARFCompileUnit *CU,
+                       uint64_t &LowPC, uint64_t &HighPC) const;
+
+  void buildAddressRangeTable(const DWARFCompileUnit *CU,
+                              DWARFDebugAranges *DebugAranges) const;
+
+  bool addressRangeContainsAddress(const DWARFCompileUnit *CU,
+                                   const uint64_t Address) const;
+
+  /// If a DIE represents a subprogram (or inlined subroutine),
+  /// returns its mangled name (or short name, if mangled is missing).
+  /// This name may be fetched from specification or abstract origin
+  /// for this subprogram. Returns null if no name is found.
+  const char* getSubroutineName(const DWARFCompileUnit *CU) const;
+
+  /// Retrieves values of DW_AT_call_file, DW_AT_call_line and
+  /// DW_AT_call_column from DIE (or zeroes if they are missing).
+  void getCallerFrame(const DWARFCompileUnit *CU, uint32_t &CallFile,
+                      uint32_t &CallLine, uint32_t &CallColumn) const;
+
+  /// InlinedChain - represents a chain of inlined_subroutine
+  /// DIEs, (possibly ending with subprogram DIE), all of which are contained
+  /// in some concrete inlined instance tree. Address range for each DIE
+  /// (except the last DIE) in this chain is contained in address
+  /// range for next DIE in the chain.
+  typedef SmallVector<DWARFDebugInfoEntryMinimal, 4> InlinedChain;
+
+  /// Get inlined chain for a given address, rooted at the current DIE.
+  /// Returns empty chain if address is not contained in address range
+  /// of current DIE.
+  InlinedChain getInlinedChainForAddress(const DWARFCompileUnit *CU,
+                                         const uint64_t Address) const;
 };
 
 }
diff --git a/lib/DebugInfo/DWARFDebugRangeList.cpp b/lib/DebugInfo/DWARFDebugRangeList.cpp
index fa15bb0ee5..1806beee72 100644
--- a/lib/DebugInfo/DWARFDebugRangeList.cpp
+++ b/lib/DebugInfo/DWARFDebugRangeList.cpp
@@ -37,10 +37,7 @@ bool DWARFDebugRangeList::extract(DataExtractor data, uint32_t *offset_ptr) {
       clear();
       return false;
     }
-    // The end of any given range list is marked by an end of list entry,
-    // which consists of a 0 for the beginning address offset
-    // and a 0 for the ending address offset.
-    if (entry.StartAddress == 0 && entry.EndAddress == 0)
+    if (entry.isEndOfListEntry())
       break;
     Entries.push_back(entry);
   }
@@ -57,3 +54,14 @@ void DWARFDebugRangeList::dump(raw_ostream &OS) const {
   }
   OS << format("%08x <End of list>\n", Offset);
 }
+
+bool DWARFDebugRangeList::containsAddress(uint64_t BaseAddress,
+                                          uint64_t Address) const {
+  for (int i = 0, n = Entries.size(); i != n; ++i) {
+    if (Entries[i].isBaseAddressSelectionEntry(AddressSize))
+      BaseAddress = Entries[i].EndAddress;
+    else if (Entries[i].containsAddress(BaseAddress, Address))
+      return true;
+  }
+  return false;
+}
diff --git a/lib/DebugInfo/DWARFDebugRangeList.h b/lib/DebugInfo/DWARFDebugRangeList.h
index b8d334f7ba..4e34a916f4 100644
--- a/lib/DebugInfo/DWARFDebugRangeList.h
+++ b/lib/DebugInfo/DWARFDebugRangeList.h
@@ -31,6 +31,29 @@ public:
     // address past the end of the address range. The ending address must
     // be greater than or equal to the beginning address.
     uint64_t EndAddress;
+    // The end of any given range list is marked by an end of list entry,
+    // which consists of a 0 for the beginning address offset
+    // and a 0 for the ending address offset.
+    bool isEndOfListEntry() const {
+      return (StartAddress == 0) && (EndAddress == 0);
+    }
+    // A base address selection entry consists of:
+    // 1. The value of the largest representable address offset
+    // (for example, 0xffffffff when the size of an address is 32 bits).
+    // 2. An address, which defines the appropriate base address for
+    // use in interpreting the beginning and ending address offsets of
+    // subsequent entries of the location list.
+    bool isBaseAddressSelectionEntry(uint8_t AddressSize) const {
+      assert(AddressSize == 4 || AddressSize == 8);
+      if (AddressSize == 4)
+        return StartAddress == -1U;
+      else
+        return StartAddress == -1ULL;
+    }
+    bool containsAddress(uint64_t BaseAddress, uint64_t Address) const {
+      return (BaseAddress + StartAddress <= Address) &&
+             (Address < BaseAddress + EndAddress);
+    }
   };
 
 private:
@@ -44,6 +67,10 @@ public:
   void clear();
   void dump(raw_ostream &OS) const;
   bool extract(DataExtractor data, uint32_t *offset_ptr);
+  /// containsAddress - Returns true if range list contains the given
+  /// address. Has to be passed base address of the compile unit that
+  /// references this range list.
+  bool containsAddress(uint64_t BaseAddress, uint64_t Address) const;
 };
 
 }  // namespace llvm