DWARF: Put all the pieces we have together and provide a single accessor to DIContext that provides line information when given an address.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139836 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/DebugInfo/DIContext.h

@@ -7,7 +7,7 @@
 //
 //===----------------------------------------------------------------------===//
 //
-// This file defines DIContext, and abstract data structure that holds
+// This file defines DIContext, an abstract data structure that holds
 // debug information data.
 //
 //===----------------------------------------------------------------------===//
@@ -21,6 +21,20 @@ namespace llvm {
 
 class raw_ostream;
 
+/// DILineInfo - a format-neutral container for source line information.
+class DILineInfo {
+  const char *FileName;
+  uint32_t Line;
+  uint32_t Column;
+public:
+  DILineInfo(const char *fileName, uint32_t line, uint32_t column)
+    : FileName(fileName), Line(line), Column(column) {}
+
+  const char *getFileName() const { return FileName; }
+  uint32_t getLine() const { return Line; }
+  uint32_t getColumn() const { return Column; }
+};
+
 class DIContext {
 public:
   virtual ~DIContext();
@@ -34,6 +48,8 @@ public:
                                     StringRef stringSection = StringRef());
 
   virtual void dump(raw_ostream &OS) = 0;
+
+  virtual DILineInfo getLineInfoForAddress(uint64_t address) = 0;
 };
 
 }

lib/DebugInfo/DWARFContext.cpp

@@ -11,6 +11,7 @@
 #include "llvm/Support/Dwarf.h"
 #include "llvm/Support/Format.h"
 #include "llvm/Support/raw_ostream.h"
+#include <algorithm>
 using namespace llvm;
 using namespace dwarf;
 
@@ -112,3 +113,51 @@ void DWARFContext::parseCompileUnits() {
     offset = CUs.back().getNextCompileUnitOffset();
   }
 }
+
+namespace {
+  struct OffsetComparator {
+    bool operator()(const DWARFCompileUnit &LHS,
+                    const DWARFCompileUnit &RHS) const {
+      return LHS.getOffset() < RHS.getOffset();
+    }
+    bool operator()(const DWARFCompileUnit &LHS, uint32_t RHS) const {
+      return LHS.getOffset() < RHS;
+    }
+    bool operator()(uint32_t LHS, const DWARFCompileUnit &RHS) const {
+      return LHS < RHS.getOffset();
+    }
+  };
+}
+
+DWARFCompileUnit *DWARFContext::getCompileUnitForOffset(uint32_t offset) {
+  if (CUs.empty())
+    parseCompileUnits();
+
+  DWARFCompileUnit *i = std::lower_bound(CUs.begin(), CUs.end(), offset,
+                                         OffsetComparator());
+  if (i != CUs.end())
+    return &*i;
+  return 0;
+}
+
+DILineInfo DWARFContext::getLineInfoForAddress(uint64_t address) {
+  // First, get the index for the arange.
+  uint32_t arangeIndex = getDebugAranges()->findAddress(address);
+  // From there, get the offset of the compile unit.
+  uint32_t cuOffset = getDebugAranges()->offsetAtIndex(arangeIndex);
+  // Retrieve the compile unit.
+  DWARFCompileUnit *cu = getCompileUnitForOffset(cuOffset);
+  // Get the line table for this compile unit.
+  const DWARFDebugLine::LineTable *lineTable = getLineTableForCompileUnit(cu);
+  // Get the index of the row we're looking for in the line table.
+  uint64_t hiPC =
+    cu->getCompileUnitDIE()->getAttributeValueAsUnsigned(cu, DW_AT_high_pc,
+                                                         -1ULL);
+  uint32_t rowIndex = lineTable->lookupAddress(address, hiPC);
+
+  // From here, contruct the DILineInfo.
+  const DWARFDebugLine::Row &row = lineTable->Rows[rowIndex];
+  const std::string &fileName = lineTable->Prologue.FileNames[row.File-1].Name;
+
+  return DILineInfo(fileName.c_str(), row.Line, row.Column);
+}

lib/DebugInfo/DWARFContext.h

@@ -53,6 +53,9 @@ public:
     return &CUs[index];
   }
 
+  /// Return the compile unit that includes an offset (relative to .debug_info).
+  DWARFCompileUnit *getCompileUnitForOffset(uint32_t offset);
+
   /// Get a pointer to the parsed DebugAbbrev object.
   const DWARFDebugAbbrev *getDebugAbbrev();
 
@@ -63,6 +66,8 @@ public:
   const DWARFDebugLine::LineTable *
   getLineTableForCompileUnit(DWARFCompileUnit *cu);
 
+  virtual DILineInfo getLineInfoForAddress(uint64_t address);
+
   bool isLittleEndian() const { return IsLittleEndian; }
 
   virtual StringRef getInfoSection() = 0;

lib/DebugInfo/DWARFDebugLine.cpp

@@ -122,7 +122,9 @@ DWARFDebugLine::getOrParseLineTable(DataExtractor debug_line_data,
     State state;
     if (!parseStatementTable(debug_line_data, &offset, state))
       return 0;
-    pos->second = state;
+    // FIXME: double lookup.
+    LineTableMap[offset] = state;
+    return &LineTableMap[offset];
   }
   return &pos->second;
 }