[LLD] Move duplicated dwarf parsing code to the Common library. NFC.

Differential Revision: https://reviews.llvm.org/D69197

llvm-svn: 375390
(cherry picked from commit 908b780)
(cherry picked from commit a18630d8a3a9bce3e9012744de371a5d5768f2db)

Author: mstorsjo

lld/COFF/InputFiles.h

@@ -10,6 +10,7 @@
 #define LLD_COFF_INPUT_FILES_H
 
 #include "Config.h"
+#include "lld/Common/DWARF.h"
 #include "lld/Common/LLVM.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/DenseMap.h"
@@ -258,6 +259,8 @@ class ObjFile : public InputFile {
   // index. Nonexistent indices (which are occupied by auxiliary
   // symbols in the real symbol table) are filled with null pointers.
   std::vector<Symbol *> Symbols;
+
+  DWARFCache *dwarf;
 };
 
 // This type represents import library members that contain DLL names

lld/Common/CMakeLists.txt

@@ -29,6 +29,7 @@ set_property(SOURCE Version.cpp APPEND PROPERTY
 
 add_lld_library(lldCommon
   Args.cpp
+  DWARF.cpp
   ErrorHandler.cpp
   Filesystem.cpp
   Memory.cpp
@@ -46,6 +47,7 @@ add_lld_library(lldCommon
   LINK_COMPONENTS
   Codegen
   Core
+  DebugInfoDWARF
   Demangle
   MC
   Option

lld/Common/DWARF.cpp

@@ -0,0 +1,103 @@
+//===- DWARF.cpp ----------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "lld/Common/DWARF.h"
+#include "lld/Common/ErrorHandler.h"
+
+using namespace llvm;
+
+namespace lld {
+
+DWARFCache::DWARFCache(std::unique_ptr<llvm::DWARFContext> d)
+    : dwarf(std::move(d)) {
+  for (std::unique_ptr<DWARFUnit> &cu : dwarf->compile_units()) {
+    auto report = [](Error err) {
+      handleAllErrors(std::move(err),
+                      [](ErrorInfoBase &info) { warn(info.message()); });
+    };
+    Expected<const DWARFDebugLine::LineTable *> expectedLT =
+        dwarf->getLineTableForUnit(cu.get(), report);
+    const DWARFDebugLine::LineTable *lt = nullptr;
+    if (expectedLT)
+      lt = *expectedLT;
+    else
+      report(expectedLT.takeError());
+    if (!lt)
+      continue;
+    lineTables.push_back(lt);
+
+    // Loop over variable records and insert them to variableLoc.
+    for (const auto &entry : cu->dies()) {
+      DWARFDie die(cu.get(), &entry);
+      // Skip all tags that are not variables.
+      if (die.getTag() != dwarf::DW_TAG_variable)
+        continue;
+
+      // Skip if a local variable because we don't need them for generating
+      // error messages. In general, only non-local symbols can fail to be
+      // linked.
+      if (!dwarf::toUnsigned(die.find(dwarf::DW_AT_external), 0))
+        continue;
+
+      // Get the source filename index for the variable.
+      unsigned file = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_file), 0);
+      if (!lt->hasFileAtIndex(file))
+        continue;
+
+      // Get the line number on which the variable is declared.
+      unsigned line = dwarf::toUnsigned(die.find(dwarf::DW_AT_decl_line), 0);
+
+      // Here we want to take the variable name to add it into variableLoc.
+      // Variable can have regular and linkage name associated. At first, we try
+      // to get linkage name as it can be different, for example when we have
+      // two variables in different namespaces of the same object. Use common
+      // name otherwise, but handle the case when it also absent in case if the
+      // input object file lacks some debug info.
+      StringRef name =
+          dwarf::toString(die.find(dwarf::DW_AT_linkage_name),
+                          dwarf::toString(die.find(dwarf::DW_AT_name), ""));
+      if (!name.empty())
+        variableLoc.insert({name, {lt, file, line}});
+    }
+  }
+}
+
+// Returns the pair of file name and line number describing location of data
+// object (variable, array, etc) definition.
+Optional<std::pair<std::string, unsigned>>
+DWARFCache::getVariableLoc(StringRef name) {
+  // Return if we have no debug information about data object.
+  auto it = variableLoc.find(name);
+  if (it == variableLoc.end())
+    return None;
+
+  // Take file name string from line table.
+  std::string fileName;
+  if (!it->second.lt->getFileNameByIndex(
+          it->second.file, {},
+          DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, fileName))
+    return None;
+
+  return std::make_pair(fileName, it->second.line);
+}
+
+// Returns source line information for a given offset
+// using DWARF debug info.
+Optional<DILineInfo> DWARFCache::getDILineInfo(uint64_t offset,
+                                               uint64_t sectionIndex) {
+  DILineInfo info;
+  for (const llvm::DWARFDebugLine::LineTable *lt : lineTables) {
+    if (lt->getFileLineInfoForAddress(
+            {offset, sectionIndex}, nullptr,
+            DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, info))
+      return info;
+  }
+  return None;
+}
+
+} // namespace lld

lld/ELF/InputFiles.cpp

@@ -17,7 +17,6 @@
 #include "lld/Common/Memory.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/CodeGen/Analysis.h"
-#include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
 #include "llvm/LTO/LTO.h"
@@ -252,57 +251,8 @@ std::string InputFile::getSrcMsg(const Symbol &Sym, InputSectionBase &Sec,
 }
 
 template <class ELFT> void ObjFile<ELFT>::initializeDwarf() {
-  Dwarf = llvm::make_unique<DWARFContext>(make_unique<LLDDwarfObj<ELFT>>(this));
-  for (std::unique_ptr<DWARFUnit> &CU : Dwarf->compile_units()) {
-    auto Report = [](Error Err) {
-      handleAllErrors(std::move(Err),
-                      [](ErrorInfoBase &Info) { warn(Info.message()); });
-    };
-    Expected<const DWARFDebugLine::LineTable *> ExpectedLT =
-        Dwarf->getLineTableForUnit(CU.get(), Report);
-    const DWARFDebugLine::LineTable *LT = nullptr;
-    if (ExpectedLT)
-      LT = *ExpectedLT;
-    else
-      Report(ExpectedLT.takeError());
-    if (!LT)
-      continue;
-    LineTables.push_back(LT);
-
-    // Loop over variable records and insert them to VariableLoc.
-    for (const auto &Entry : CU->dies()) {
-      DWARFDie Die(CU.get(), &Entry);
-      // Skip all tags that are not variables.
-      if (Die.getTag() != dwarf::DW_TAG_variable)
-        continue;
-
-      // Skip if a local variable because we don't need them for generating
-      // error messages. In general, only non-local symbols can fail to be
-      // linked.
-      if (!dwarf::toUnsigned(Die.find(dwarf::DW_AT_external), 0))
-        continue;
-
-      // Get the source filename index for the variable.
-      unsigned File = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_file), 0);
-      if (!LT->hasFileAtIndex(File))
-        continue;
-
-      // Get the line number on which the variable is declared.
-      unsigned Line = dwarf::toUnsigned(Die.find(dwarf::DW_AT_decl_line), 0);
-
-      // Here we want to take the variable name to add it into VariableLoc.
-      // Variable can have regular and linkage name associated. At first, we try
-      // to get linkage name as it can be different, for example when we have
-      // two variables in different namespaces of the same object. Use common
-      // name otherwise, but handle the case when it also absent in case if the
-      // input object file lacks some debug info.
-      StringRef Name =
-          dwarf::toString(Die.find(dwarf::DW_AT_linkage_name),
-                          dwarf::toString(Die.find(dwarf::DW_AT_name), ""));
-      if (!Name.empty())
-        VariableLoc.insert({Name, {LT, File, Line}});
-    }
-  }
+  dwarf = make<DWARFCache>(std::make_unique<DWARFContext>(
+      std::make_unique<LLDDwarfObj<ELFT>>(this)));
 }
 
 // Returns the pair of file name and line number describing location of data
@@ -312,19 +262,7 @@ Optional<std::pair<std::string, unsigned>>
 ObjFile<ELFT>::getVariableLoc(StringRef Name) {
   llvm::call_once(InitDwarfLine, [this]() { initializeDwarf(); });
 
-  // Return if we have no debug information about data object.
-  auto It = VariableLoc.find(Name);
-  if (It == VariableLoc.end())
-    return None;
-
-  // Take file name string from line table.
-  std::string FileName;
-  if (!It->second.LT->getFileNameByIndex(
-          It->second.File, nullptr,
-          DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, FileName))
-    return None;
-
-  return std::make_pair(FileName, It->second.Line);
+  return dwarf->getVariableLoc(Name);
 }
 
 // Returns source line information for a given offset
@@ -346,14 +284,7 @@ Optional<DILineInfo> ObjFile<ELFT>::getDILineInfo(InputSectionBase *S,
 
   // Use fake address calcuated by adding section file offset and offset in
   // section. See comments for ObjectInfo class.
-  DILineInfo Info;
-  for (const llvm::DWARFDebugLine::LineTable *LT : LineTables) {
-    if (LT->getFileLineInfoForAddress(
-            {S->getOffsetInFile() + Offset, SectionIndex}, nullptr,
-            DILineInfoSpecifier::FileLineInfoKind::AbsoluteFilePath, Info))
-      return Info;
-  }
-  return None;
+  return dwarf->getDILineInfo(S->getOffsetInFile() + Offset, SectionIndex);
 }
 
 // Returns "<internal>", "foo.a(bar.o)" or "baz.o".

lld/ELF/InputFiles.h

@@ -10,13 +10,13 @@
 #define LLD_ELF_INPUT_FILES_H
 
 #include "Config.h"
+#include "lld/Common/DWARF.h"
 #include "lld/Common/ErrorHandler.h"
 #include "lld/Common/LLVM.h"
 #include "lld/Common/Reproduce.h"
 #include "llvm/ADT/CachedHashString.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/STLExtras.h"
-#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
 #include "llvm/IR/Comdat.h"
 #include "llvm/Object/Archive.h"
 #include "llvm/Object/ELF.h"
@@ -26,7 +26,6 @@
 
 namespace llvm {
 class TarWriter;
-struct DILineInfo;
 namespace lto {
 class InputFile;
 }
@@ -284,14 +283,7 @@ template <class ELFT> class ObjFile : public ELFFileBase {
   // reporting. Linker may find reasonable number of errors in a
   // single object file, so we cache debugging information in order to
   // parse it only once for each object file we link.
-  std::unique_ptr<llvm::DWARFContext> Dwarf;
-  std::vector<const llvm::DWARFDebugLine::LineTable *> LineTables;
-  struct VarLoc {
-    const llvm::DWARFDebugLine::LineTable *LT;
-    unsigned File;
-    unsigned Line;
-  };
-  llvm::DenseMap<StringRef, VarLoc> VariableLoc;
+  DWARFCache *dwarf;
   llvm::once_flag InitDwarfLine;
 };
 

lld/include/lld/Common/DWARF.h

@@ -0,0 +1,47 @@
+//===- DWARF.h --------------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_DWARF_H
+#define LLD_DWARF_H
+
+#include "lld/Common/LLVM.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFDebugLine.h"
+#include <memory>
+#include <string>
+
+namespace llvm {
+struct DILineInfo;
+} // namespace llvm
+
+namespace lld {
+
+class DWARFCache {
+public:
+  DWARFCache(std::unique_ptr<llvm::DWARFContext> dwarf);
+  llvm::Optional<llvm::DILineInfo> getDILineInfo(uint64_t offset,
+                                                 uint64_t sectionIndex);
+  llvm::Optional<std::pair<std::string, unsigned>>
+  getVariableLoc(StringRef name);
+
+private:
+  std::unique_ptr<llvm::DWARFContext> dwarf;
+  std::vector<const llvm::DWARFDebugLine::LineTable *> lineTables;
+  struct VarLoc {
+    const llvm::DWARFDebugLine::LineTable *lt;
+    unsigned file;
+    unsigned line;
+  };
+  llvm::DenseMap<StringRef, VarLoc> variableLoc;
+};
+
+} // namespace lld
+
+#endif