Add convenience methods to convert LLDB to LLVM data structures.

This patch adds two convenience methods named GetAsLLVM to the LLDB
counterparts of the DWARF DataExtractor and the DWARF context. The
DWARFContext, once created, is cached for future usage.

Differential revision: https://reviews.llvm.org/D64535

llvm-svn: 365819

lldb/include/lldb/Core/Section.h

@@ -38,6 +38,11 @@ public:
   typedef collection::iterator iterator;
   typedef collection::const_iterator const_iterator;
 
+  const_iterator begin() const { return m_sections.begin(); }
+  const_iterator end() const { return m_sections.end(); }
+  const_iterator begin() { return m_sections.begin(); }
+  const_iterator end() { return m_sections.end(); }
+
   SectionList();
 
   ~SectionList();

lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.cpp

@@ -100,3 +100,37 @@ const DWARFDataExtractor &DWARFContext::getOrLoadDebugTypesData() {
   return LoadOrGetSection(eSectionTypeDWARFDebugTypes,
                           eSectionTypeDWARFDebugTypesDwo, m_data_debug_types);
 }
+
+llvm::DWARFContext &DWARFContext::GetAsLLVM() {
+  if (!m_llvm_context) {
+    llvm::StringMap<std::unique_ptr<llvm::MemoryBuffer>> section_map;
+    uint8_t addr_size = 0;
+
+    auto AddSection = [&](Section &section) {
+      DataExtractor section_data;
+      section.GetSectionData(section_data);
+
+      // Set the address size the first time we see it.
+      if (addr_size == 0)
+        addr_size = section_data.GetByteSize();
+
+      llvm::StringRef data = llvm::toStringRef(section_data.GetData());
+      llvm::StringRef name = section.GetName().GetStringRef();
+      section_map.try_emplace(
+          name, llvm::MemoryBuffer::getMemBuffer(data, name, false));
+    };
+
+    if (m_main_section_list) {
+      for (auto &section : *m_main_section_list)
+        AddSection(*section);
+    }
+
+    if (m_dwo_section_list) {
+      for (auto &section : *m_dwo_section_list)
+        AddSection(*section);
+    }
+
+    m_llvm_context = llvm::DWARFContext::create(section_map, addr_size);
+  }
+  return *m_llvm_context;
+}

lldb/source/Plugins/SymbolFile/DWARF/DWARFContext.h

@@ -12,6 +12,7 @@
 #include "DWARFDataExtractor.h"
 #include "lldb/Core/Section.h"
 #include "llvm/ADT/Optional.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/Support/Threading.h"
 #include <memory>
 
@@ -20,6 +21,7 @@ class DWARFContext {
 private:
   SectionList *m_main_section_list;
   SectionList *m_dwo_section_list;
+  mutable std::unique_ptr<llvm::DWARFContext> m_llvm_context;
 
   struct SectionData {
     llvm::once_flag flag;
@@ -64,6 +66,8 @@ public:
   const DWARFDataExtractor &getOrLoadStrData();
   const DWARFDataExtractor &getOrLoadStrOffsetsData();
   const DWARFDataExtractor &getOrLoadDebugTypesData();
+
+  llvm::DWARFContext &GetAsLLVM();
 };
 } // namespace lldb_private
 

lldb/source/Plugins/SymbolFile/DWARF/DWARFDataExtractor.cpp

@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "DWARFDataExtractor.h"
+#include "llvm/ADT/StringRef.h"
 
 namespace lldb_private {
 
@@ -19,4 +20,11 @@ dw_offset_t
 DWARFDataExtractor::GetDWARFOffset(lldb::offset_t *offset_ptr) const {
   return GetMaxU64(offset_ptr, GetDWARFSizeOfOffset());
 }
+
+llvm::DWARFDataExtractor DWARFDataExtractor::GetAsLLVM() const {
+  return llvm::DWARFDataExtractor(
+      llvm::StringRef(reinterpret_cast<const char *>(GetDataStart()),
+                      GetByteSize()),
+      GetByteOrder() == lldb::eByteOrderLittle, GetAddressByteSize());
 }
+} // namespace lldb_private

lldb/source/Plugins/SymbolFile/DWARF/DWARFDataExtractor.h

@@ -11,6 +11,7 @@
 
 #include "lldb/Core/dwarf.h"
 #include "lldb/Utility/DataExtractor.h"
+#include "llvm/DebugInfo/DWARF/DWARFDataExtractor.h"
 
 namespace lldb_private {
 
@@ -28,6 +29,8 @@ public:
 
   size_t GetDWARFSizeofInitialLength() const { return 4; }
   size_t GetDWARFSizeOfOffset() const { return 4; }
+
+  llvm::DWARFDataExtractor GetAsLLVM() const;
 };
 }
 

lldb/source/Plugins/SymbolFile/DWARF/DebugNamesDWARFIndex.cpp

@@ -16,13 +16,6 @@
 using namespace lldb_private;
 using namespace lldb;
 
-static llvm::DWARFDataExtractor ToLLVM(const DWARFDataExtractor &data) {
-  return llvm::DWARFDataExtractor(
-      llvm::StringRef(reinterpret_cast<const char *>(data.GetDataStart()),
-                      data.GetByteSize()),
-      data.GetByteOrder() == eByteOrderLittle, data.GetAddressByteSize());
-}
-
 llvm::Expected<std::unique_ptr<DebugNamesDWARFIndex>>
 DebugNamesDWARFIndex::Create(Module &module, DWARFDataExtractor debug_names,
                              DWARFDataExtractor debug_str,
@@ -31,8 +24,8 @@ DebugNamesDWARFIndex::Create(Module &module, DWARFDataExtractor debug_names,
     return llvm::make_error<llvm::StringError>("debug info null",
                                                llvm::inconvertibleErrorCode());
   }
-  auto index_up =
-      llvm::make_unique<DebugNames>(ToLLVM(debug_names), ToLLVM(debug_str));
+  auto index_up = llvm::make_unique<DebugNames>(debug_names.GetAsLLVM(),
+                                                debug_str.GetAsLLVM());
   if (llvm::Error E = index_up->extract())
     return std::move(E);
 

lldb/tools/lldb-test/lldb-test.cpp

@@ -739,7 +739,7 @@ static void dumpSectionList(LinePrinter &Printer, const SectionList &List, bool
     Printer.formatLine("File size: {0}", S->GetFileSize());
 
     if (opts::object::SectionContents) {
-      DataExtractor Data;
+      lldb_private::DataExtractor Data;
       S->GetSectionData(Data);
       ArrayRef<uint8_t> Bytes = {Data.GetDataStart(), Data.GetDataEnd()};
       Printer.formatBinary("Data: ", Bytes, 0);