Add support for applying in-memory relocations to the .debug_line section and, in the case of ELF files, using symbol addresses when available for relocations to the .debug_info section. Also extending the llvm-rtdyld tool to add the ability to dump line number information for testing purposes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@173517 91177308-0d34-0410-b5e6-96231b3b80d8

lib/DebugInfo/DWARFCompileUnit.h

@@ -13,6 +13,7 @@
 #include "DWARFDebugAbbrev.h"
 #include "DWARFDebugInfoEntry.h"
 #include "DWARFDebugRangeList.h"
+#include "DWARFRelocMap.h"
 #include <vector>
 
 namespace llvm {
@@ -20,7 +21,6 @@ namespace llvm {
 class DWARFDebugAbbrev;
 class StringRef;
 class raw_ostream;
-typedef DenseMap<uint64_t, std::pair<uint8_t, int64_t> > RelocAddrMap;
 
 class DWARFCompileUnit {
   const DWARFDebugAbbrev *Abbrev;

lib/DebugInfo/DWARFContext.cpp

@@ -53,7 +53,7 @@ void DWARFContext::dump(raw_ostream &OS, DIDumpType DumpType) {
         DataExtractor lineData(getLineSection(), isLittleEndian(),
                                savedAddressByteSize);
         DWARFDebugLine::DumpingState state(OS);
-        DWARFDebugLine::parseStatementTable(lineData, &stmtOffset, state);
+        DWARFDebugLine::parseStatementTable(lineData, &lineRelocMap(), &stmtOffset, state);
       }
     }
   }
@@ -155,7 +155,7 @@ const DWARFDebugAranges *DWARFContext::getDebugAranges() {
 const DWARFLineTable *
 DWARFContext::getLineTableForCompileUnit(DWARFCompileUnit *cu) {
   if (!Line)
-    Line.reset(new DWARFDebugLine());
+    Line.reset(new DWARFDebugLine(&lineRelocMap()));
 
   unsigned stmtOffset =
     cu->getCompileUnitDIE()->getAttributeValueAsUnsigned(cu, DW_AT_stmt_list,
@@ -422,12 +422,15 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj) :
     else
       continue;
 
-    // TODO: For now only handle relocations for the debug_info section.
+    // TODO: Add support for relocations in other sections as needed.
+    // Record relocations for the debug_info and debug_line sections.
     RelocAddrMap *Map;
     if (name == "debug_info")
       Map = &InfoRelocMap;
     else if (name == "debug_info.dwo")
       Map = &InfoDWORelocMap;
+    else if (name == "debug_line")
+      Map = &LineRelocMap;
     else
       continue;
 
@@ -441,10 +444,17 @@ DWARFContextInMemory::DWARFContextInMemory(object::ObjectFile *Obj) :
         reloc_i->getAddress(Address);
         uint64_t Type;
         reloc_i->getType(Type);
+        uint64_t SymAddr = 0;
+        // ELF relocations may need the symbol address
+        if (Obj->isELF()) {
+          object::SymbolRef Sym;
+          reloc_i->getSymbol(Sym);
+          Sym.getAddress(SymAddr);
+        }
 
         object::RelocVisitor V(Obj->getFileFormatName());
         // The section address is always 0 for debug sections.
-        object::RelocToApply R(V.visit(Type, *reloc_i));
+        object::RelocToApply R(V.visit(Type, *reloc_i, 0, SymAddr));
         if (V.error()) {
           SmallString<32> Name;
           error_code ec(reloc_i->getTypeName(Name));

lib/DebugInfo/DWARFContext.h

@@ -95,6 +95,7 @@ public:
 
   virtual bool isLittleEndian() const = 0;
   virtual const RelocAddrMap &infoRelocMap() const = 0;
+  virtual const RelocAddrMap &lineRelocMap() const = 0;
   virtual StringRef getInfoSection() = 0;
   virtual StringRef getAbbrevSection() = 0;
   virtual StringRef getARangeSection() = 0;
@@ -130,6 +131,7 @@ class DWARFContextInMemory : public DWARFContext {
   virtual void anchor();
   bool IsLittleEndian;
   RelocAddrMap InfoRelocMap;
+  RelocAddrMap LineRelocMap;
   StringRef InfoSection;
   StringRef AbbrevSection;
   StringRef ARangeSection;
@@ -150,6 +152,7 @@ public:
   DWARFContextInMemory(object::ObjectFile *);
   virtual bool isLittleEndian() const { return IsLittleEndian; }
   virtual const RelocAddrMap &infoRelocMap() const { return InfoRelocMap; }
+  virtual const RelocAddrMap &lineRelocMap() const { return LineRelocMap; }
   virtual StringRef getInfoSection() { return InfoSection; }
   virtual StringRef getAbbrevSection() { return AbbrevSection; }
   virtual StringRef getARangeSection() { return ARangeSection; }

lib/DebugInfo/DWARFDebugLine.cpp

@@ -155,7 +155,7 @@ DWARFDebugLine::getOrParseLineTable(DataExtractor debug_line_data,
   if (pos.second) {
     // Parse and cache the line table for at this offset.
     State state;
-    if (!parseStatementTable(debug_line_data, &offset, state))
+    if (!parseStatementTable(debug_line_data, RelocMap, &offset, state))
       return 0;
     pos.first->second = state;
   }
@@ -219,7 +219,8 @@ DWARFDebugLine::parsePrologue(DataExtractor debug_line_data,
 }
 
 bool
-DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data,
+DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data, 
+                                    const RelocAddrMap *RMap,
                                     uint32_t *offset_ptr, State &state) {
   const uint32_t debug_line_offset = *offset_ptr;
 
@@ -268,7 +269,15 @@ DWARFDebugLine::parseStatementTable(DataExtractor debug_line_data,
         // relocatable address. All of the other statement program opcodes
         // that affect the address register add a delta to it. This instruction
         // stores a relocatable value into it instead.
-        state.Address = debug_line_data.getAddress(offset_ptr);
+        {
+          // If this address is in our relocation map, apply the relocation.
+          RelocAddrMap::const_iterator AI = RMap->find(*offset_ptr);
+          if (AI != RMap->end()) {
+             const std::pair<uint8_t, int64_t> &R = AI->second;
+             state.Address = debug_line_data.getAddress(offset_ptr) + R.second;
+          } else
+            state.Address = debug_line_data.getAddress(offset_ptr);
+        }
         break;
 
       case DW_LNE_define_file:

lib/DebugInfo/DWARFDebugLine.h

@@ -10,6 +10,7 @@
 #ifndef LLVM_DEBUGINFO_DWARFDEBUGLINE_H
 #define LLVM_DEBUGINFO_DWARFDEBUGLINE_H
 
+#include "DWARFRelocMap.h"
 #include "llvm/Support/DataExtractor.h"
 #include <map>
 #include <string>
@@ -21,6 +22,7 @@ class raw_ostream;
 
 class DWARFDebugLine {
 public:
+  DWARFDebugLine(const RelocAddrMap* LineInfoRelocMap) : RelocMap(LineInfoRelocMap) {}
   struct FileNameEntry {
     FileNameEntry() : Name(0), DirIdx(0), ModTime(0), Length(0) {}
 
@@ -227,6 +229,7 @@ public:
                             Prologue *prologue);
   /// Parse a single line table (prologue and all rows).
   static bool parseStatementTable(DataExtractor debug_line_data,
+                                  const RelocAddrMap *RMap,
                                   uint32_t *offset_ptr, State &state);
 
   const LineTable *getLineTable(uint32_t offset) const;
@@ -238,6 +241,7 @@ private:
   typedef LineTableMapTy::iterator LineTableIter;
   typedef LineTableMapTy::const_iterator LineTableConstIter;
 
+  const RelocAddrMap *RelocMap;
   LineTableMapTy LineTableMap;
 };
 

lib/DebugInfo/DWARFRelocMap.h

@@ -0,0 +1,21 @@
+//===-- DWARFRelocMap.h -----------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_DEBUGINFO_DWARFRELOCMAP_H
+#define LLVM_DEBUGINFO_DWARFRELOCMAP_H
+
+#include "llvm/ADT/DenseMap.h"
+
+namespace llvm {
+
+typedef DenseMap<uint64_t, std::pair<uint8_t, int64_t> > RelocAddrMap;
+
+} // namespace llvm
+
+#endif // LLVM_DEBUGINFO_DWARFRELOCMAP_H