[Dsymutil][Debuginfo][NFC] Reland: Refactor dsymutil to separate DWARF optimizing part. rust-lang#2.

Summary:
This patch relands D71271. The problem with D71271 is that it has cyclic dependency:
CodeGen->AsmPrinter->DebugInfoDWARF->CodeGen. To avoid cyclic dependency this patch
puts implementation for DWARFOptimizer into separate library: lib/DWARFLinker.

Thus the difference between this patch and D71271 is in that DWARFOptimizer renamed into
DWARFLinker and it`s files are put into lib/DWARFLinker.

Reviewers: JDevlieghere, friss, dblaikie, aprantl

Reviewed By: JDevlieghere

Subscribers: thegameg, merge_guards_bot, probinson, mgorny, hiraditya, llvm-commits

Tags: #llvm, #debug-info

Differential Revision: https://reviews.llvm.org/D71839

Author: avl-llvm

llvm/include/llvm/CodeGen/NonRelocatableStringpool.h

@@ -1,4 +1,4 @@
-//===- llvm/CodeGen/NonRelocatableStringpool.h - A simple stringpool  -----===//
+//===- NonRelocatableStringpool.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.

llvm/include/llvm/DWARFLinker/DWARFLinker.h

@@ -0,0 +1,86 @@
+//===- DWARFLinker.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 LLVM_DWARFLINKER_DWARFLINKER_H
+#define LLVM_DWARFLINKER_DWARFLINKER_H
+
+#include "llvm/CodeGen/NonRelocatableStringpool.h"
+#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
+#include "llvm/DebugInfo/DWARF/DWARFCompileUnit.h"
+#include "llvm/DebugInfo/DWARF/DWARFContext.h"
+#include <map>
+
+namespace llvm {
+
+enum class DwarfLinkerClient { Dsymutil, LLD, General };
+
+/// Partial address range. Besides an offset, only the
+/// HighPC is stored. The structure is stored in a map where the LowPC is the
+/// key.
+struct ObjFileAddressRange {
+  /// Function HighPC.
+  uint64_t HighPC;
+  /// Offset to apply to the linked address.
+  /// should be 0 for not-linked object file.
+  int64_t Offset;
+
+  ObjFileAddressRange(uint64_t EndPC, int64_t Offset)
+      : HighPC(EndPC), Offset(Offset) {}
+
+  ObjFileAddressRange() : HighPC(0), Offset(0) {}
+};
+
+/// Map LowPC to ObjFileAddressRange.
+using RangesTy = std::map<uint64_t, ObjFileAddressRange>;
+
+/// AddressesMap represents information about valid addresses used
+/// by debug information. Valid addresses are those which points to
+/// live code sections. i.e. relocations for these addresses point
+/// into sections which would be/are placed into resulting binary.
+class AddressesMap {
+public:
+  virtual ~AddressesMap();
+
+  /// Returns true if represented addresses are from linked file.
+  /// Returns false if represented addresses are from not-linked
+  /// object file.
+  virtual bool areRelocationsResolved() const = 0;
+
+  /// Checks that there are valid relocations against a .debug_info
+  /// section. Reset current relocation pointer if neccessary.
+  virtual bool hasValidRelocs(bool ResetRelocsPtr = true) = 0;
+
+  /// Checks that there is a relocation against .debug_info
+  /// table between \p StartOffset and \p NextOffset.
+  ///
+  /// This function must be called with offsets in strictly ascending
+  /// order because it never looks back at relocations it already 'went past'.
+  /// \returns true and sets Info.InDebugMap if it is the case.
+  virtual bool hasValidRelocationAt(uint64_t StartOffset, uint64_t EndOffset,
+                                    CompileUnit::DIEInfo &Info) = 0;
+
+  /// Apply the valid relocations to the buffer \p Data, taking into
+  /// account that Data is at \p BaseOffset in the debug_info section.
+  ///
+  /// This function must be called with monotonic \p BaseOffset values.
+  ///
+  /// \returns true whether any reloc has been applied.
+  virtual bool applyValidRelocs(MutableArrayRef<char> Data, uint64_t BaseOffset,
+                                bool IsLittleEndian) = 0;
+
+  /// Returns all valid functions address ranges(i.e., those ranges
+  /// which points to sections with code).
+  virtual RangesTy &getValidAddressRanges() = 0;
+
+  /// Erases all data.
+  virtual void clear() = 0;
+};
+
+} // end namespace llvm
+
+#endif // LLVM_DWARFLINKER_DWARFLINKER_H

llvm/tools/dsymutil/CompileUnit.h renamed to llvm/include/llvm/DWARFLinker/DWARFLinkerCompileUnit.h

@@ -1,20 +1,20 @@
-//===- tools/dsymutil/CompileUnit.h - Dwarf debug info linker ---*- C++ -*-===//
+//===- DWARFLinkerCompileUnit.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 LLVM_TOOLS_DSYMUTIL_COMPILEUNIT_H
-#define LLVM_TOOLS_DSYMUTIL_COMPILEUNIT_H
+#ifndef LLVM_DWARFLINKER_DWARFLINKERCOMPILEUNIT_H
+#define LLVM_DWARFLINKER_DWARFLINKERCOMPILEUNIT_H
 
 #include "llvm/ADT/IntervalMap.h"
 #include "llvm/CodeGen/DIE.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
+#include "llvm/Support/DataExtractor.h"
 
 namespace llvm {
-namespace dsymutil {
 
 class DeclContext;
 
@@ -46,7 +46,7 @@ struct PatchLocation {
 };
 
 /// Stores all information relating to a compile unit, be it in its original
-/// instance in the object file to its brand new cloned and linked DIE tree.
+/// instance in the object file to its brand new cloned and generated DIE tree.
 class CompileUnit {
 public:
   /// Information gathered about a DIE in the object file.
@@ -325,7 +325,6 @@ class CompileUnit {
   std::string ClangModuleName;
 };
 
-} // end namespace dsymutil
 } // end namespace llvm
 
-#endif // LLVM_TOOLS_DSYMUTIL_COMPILEUNIT_H
+#endif // LLVM_DWARFLINKER_DWARFLINKERCOMPILEUNIT_H

llvm/tools/dsymutil/DeclContext.h renamed to llvm/include/llvm/DWARFLinker/DWARFLinkerDeclContext.h

@@ -1,25 +1,24 @@
-//===- tools/dsymutil/DeclContext.h - Dwarf debug info linker ---*- C++ -*-===//
+//===- DWARFLinkerDeclContext.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 LLVM_TOOLS_DSYMUTIL_DECLCONTEXT_H
-#define LLVM_TOOLS_DSYMUTIL_DECLCONTEXT_H
+#ifndef LLVM_DWARFLINKER_DWARFLINKERDECLCONTEXT_H
+#define LLVM_DWARFLINKER_DWARFLINKERDECLCONTEXT_H
 
-#include "CompileUnit.h"
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/DenseMapInfo.h"
 #include "llvm/ADT/DenseSet.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/CodeGen/NonRelocatableStringpool.h"
+#include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/Support/Path.h"
 
 namespace llvm {
-namespace dsymutil {
 
 struct DeclMapInfo;
 
@@ -165,7 +164,6 @@ struct DeclMapInfo : private DenseMapInfo<DeclContext *> {
   }
 };
 
-} // end namespace dsymutil
 } // end namespace llvm
 
-#endif // LLVM_TOOLS_DSYMUTIL_DECLCONTEXT_H
+#endif // LLVM_DWARFLINKER_DWARFLINKERDECLCONTEXT_H

llvm/lib/CMakeLists.txt

@@ -8,6 +8,7 @@ add_subdirectory(CodeGen)
 add_subdirectory(BinaryFormat)
 add_subdirectory(Bitcode)
 add_subdirectory(Bitstream)
+add_subdirectory(DWARFLinker)
 add_subdirectory(Frontend)
 add_subdirectory(Transforms)
 add_subdirectory(Linker)

llvm/lib/CodeGen/NonRelocatableStringpool.cpp

@@ -1,4 +1,4 @@
-//===-- llvm/CodeGen/NonRelocatableStringpool.cpp - A simple stringpool  --===//
+//===-- NonRelocatableStringpool.cpp --------------------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.

llvm/lib/DWARFLinker/CMakeLists.txt

@@ -0,0 +1,6 @@
+add_llvm_component_library(LLVMDWARFLinker
+  DWARFLinkerCompileUnit.cpp
+  DWARFLinkerDeclContext.cpp
+  DWARFLinker.cpp
+
+  )

llvm/lib/DWARFLinker/DWARFLinker.cpp

@@ -0,0 +1,15 @@
+//=== DWARFLinker.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 "llvm/DWARFLinker/DWARFLinker.h"
+
+namespace llvm {
+
+AddressesMap::~AddressesMap() {}
+
+} // namespace llvm

llvm/tools/dsymutil/CompileUnit.cpp renamed to llvm/lib/DWARFLinker/DWARFLinkerCompileUnit.cpp

@@ -1,16 +1,15 @@
-//===- tools/dsymutil/CompileUnit.h - Dwarf compile unit ------------------===//
+//===- DWARFLinkerCompileUnit.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 "CompileUnit.h"
-#include "DeclContext.h"
+#include "llvm/DWARFLinker/DWARFLinkerCompileUnit.h"
+#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
 
 namespace llvm {
-namespace dsymutil {
 
 /// Check if the DIE at \p Idx is in the scope of a function.
 static bool inFunctionScope(CompileUnit &U, unsigned Idx) {
@@ -142,5 +141,4 @@ void CompileUnit::addTypeAccelerator(const DIE *Die,
   Pubtypes.emplace_back(Name, Die, QualifiedNameHash, ObjcClassImplementation);
 }
 
-} // namespace dsymutil
 } // namespace llvm

llvm/tools/dsymutil/DeclContext.cpp renamed to llvm/lib/DWARFLinker/DWARFLinkerDeclContext.cpp

@@ -1,18 +1,17 @@
-//===- tools/dsymutil/DeclContext.cpp - Declaration context ---------------===//
+//===- DWARFLinkerDeclContext.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 "DeclContext.h"
+#include "llvm/DWARFLinker/DWARFLinkerDeclContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFContext.h"
 #include "llvm/DebugInfo/DWARF/DWARFDie.h"
 #include "llvm/DebugInfo/DWARF/DWARFUnit.h"
 
 namespace llvm {
-namespace dsymutil {
 
 /// Set the last DIE/CU a context was seen in and, possibly invalidate the
 /// context if it is ambiguous.
@@ -206,5 +205,5 @@ PointerIntPair<DeclContext *, 1> DeclContextTree::getChildDeclContext(
 
   return PointerIntPair<DeclContext *, 1>(*ContextIter);
 }
-} // namespace dsymutil
+
 } // namespace llvm