[dsymutil] Add DwarfLinker class.

It's an empty shell for now. It's main method just opens the debug
map objects and parses their Dwarf info. Test that we at least do
that correctly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227337 91177308-0d34-0410-b5e6-96231b3b80d8

test/tools/dsymutil/basic-linking.test

@@ -0,0 +1,54 @@
+RUN: llvm-dsymutil -v -oso-prepend-path=%p %p/Inputs/basic.macho.x86_64 | FileCheck %s
+RUN: llvm-dsymutil -v -oso-prepend-path=%p %p/Inputs/basic-lto.macho.x86_64 | FileCheck %s --check-prefix=CHECK-LTO
+RUN: llvm-dsymutil -v -oso-prepend-path=%p %p/Inputs/basic-archive.macho.x86_64 | FileCheck %s --check-prefix=CHECK-ARCHIVE
+
+This test check the basic Dwarf linking process through the debug dumps.
+
+CHECK: DEBUG MAP OBJECT: {{.*}}basic1.macho.x86_64.o
+CHECK: Input compilation unit:
+CHECK-NEXT: TAG_compile_unit
+CHECK-NOT: TAG
+CHECK: AT_name {{.*}}basic1.c
+CHECK: DEBUG MAP OBJECT: {{.*}}basic2.macho.x86_64.o
+CHECK: Input compilation unit:
+CHECK-NEXT: TAG_compile_unit
+CHECK-NOT: TAG
+CHECK: AT_name {{.*}}basic2.c
+CHECK: DEBUG MAP OBJECT: {{.*}}basic3.macho.x86_64.o
+CHECK: Input compilation unit:
+CHECK-NEXT: TAG_compile_unit
+CHECK-NOT: TAG
+CHECK: AT_name {{.*}}basic3.c
+
+
+CHECK-LTO: DEBUG MAP OBJECT: {{.*}}basic-lto.macho.x86_64.o
+CHECK-LTO: Input compilation unit:
+CHECK-LTO-NEXT: TAG_compile_unit
+CHECK-LTO-NOT: TAG
+CHECK-LTO: AT_name {{.*}}basic1.c
+CHECK-LTO: Input compilation unit:
+CHECK-LTO-NEXT: TAG_compile_unit
+CHECK-LTO-NOT: TAG
+CHECK-LTO: AT_name {{.*}}basic2.c
+CHECK-LTO: Input compilation unit:
+CHECK-LTO-NEXT: TAG_compile_unit
+CHECK-LTO-NOT: TAG
+CHECK-LTO: AT_name {{.*}}basic3.c
+
+
+CHECK-ARCHIVE: DEBUG MAP OBJECT: {{.*}}basic1.macho.x86_64.o
+CHECK-ARCHIVE: Input compilation unit:
+CHECK-ARCHIVE-NEXT: TAG_compile_unit
+CHECK-ARCHIVE-NOT: TAG
+CHECK-ARCHIVE: AT_name {{.*}}basic1.c
+CHECK-ARCHIVE: DEBUG MAP OBJECT: {{.*}}libbasic.a(basic2.macho.x86_64.o)
+CHECK-ARCHIVE: Input compilation unit:
+CHECK-ARCHIVE-NEXT: TAG_compile_unit
+CHECK-ARCHIVE-NOT: TAG
+CHECK-ARCHIVE: AT_name {{.*}}basic2.c
+CHECK-ARCHIVE: DEBUG MAP OBJECT: {{.*}}libbasic.a(basic3.macho.x86_64.o)
+CHECK-ARCHIVE: Input compilation unit:
+CHECK-ARCHIVE-NEXT: TAG_compile_unit
+CHECK-ARCHIVE-NOT: TAG
+CHECK-ARCHIVE: AT_name {{.*}}basic3.c
+

tools/dsymutil/CMakeLists.txt

@@ -1,4 +1,5 @@
 set(LLVM_LINK_COMPONENTS
+  DebugInfo
   Object
   Support
   )

tools/dsymutil/DwarfLinker.cpp

@@ -7,14 +7,68 @@
 //
 //===----------------------------------------------------------------------===//
 #include "DebugMap.h"
+
+#include "BinaryHolder.h"
+#include "DebugMap.h"
 #include "dsymutil.h"
+#include "llvm/DebugInfo/DWARFContext.h"
+#include "llvm/DebugInfo/DWARFDebugInfoEntry.h"
+#include <string>
 
 namespace llvm {
 namespace dsymutil {
 
-bool linkDwarf(StringRef OutputFilename, const DebugMap &DM, bool Verbose) {
-  // Do nothing for now.
+namespace {
+
+/// \brief The core of the Dwarf linking logic.
+class DwarfLinker {
+public:
+  DwarfLinker(StringRef OutputFilename, bool Verbose)
+      : OutputFilename(OutputFilename), Verbose(Verbose), BinHolder(Verbose) {}
+
+  /// \brief Link the contents of the DebugMap.
+  bool link(const DebugMap &);
+
+private:
+  std::string OutputFilename;
+  bool Verbose;
+  BinaryHolder BinHolder;
+};
+
+bool DwarfLinker::link(const DebugMap &Map) {
+
+  if (Map.begin() == Map.end()) {
+    errs() << "Empty debug map.\n";
+    return false;
+  }
+
+  for (const auto &Obj : Map.objects()) {
+    if (Verbose)
+      outs() << "DEBUG MAP OBJECT: " << Obj->getObjectFilename() << "\n";
+    auto ErrOrObj = BinHolder.GetObjectFile(Obj->getObjectFilename());
+    if (std::error_code EC = ErrOrObj.getError()) {
+      errs() << Obj->getObjectFilename() << ": " << EC.message() << "\n";
+      continue;
+    }
+
+    DWARFContextInMemory DwarfContext(*ErrOrObj);
+
+    for (const auto &CU : DwarfContext.compile_units()) {
+      auto *CUDie = CU->getCompileUnitDIE(false);
+      if (Verbose) {
+        outs() << "Input compilation unit:";
+        CUDie->dump(outs(), CU.get(), 0);
+      }
+    }
+  }
+
   return true;
 }
 }
+
+bool linkDwarf(StringRef OutputFilename, const DebugMap &DM, bool Verbose) {
+  DwarfLinker Linker(OutputFilename, Verbose);
+  return Linker.link(DM);
+}
+}
 }

tools/dsymutil/LLVMBuild.txt

@@ -19,4 +19,4 @@
 type = Tool
 name = llvm-dsymutil
 parent = Tools
-required_libraries = Object Support
+required_libraries = DebugInfo Object Support

tools/dsymutil/Makefile

@@ -9,7 +9,7 @@
 
 LEVEL := ../..
 TOOLNAME := llvm-dsymutil
-LINK_COMPONENTS := Object Support
+LINK_COMPONENTS := DebugInfo Object Support
 
 # This tool has no plugins, optimize startup time.
 TOOL_NO_EXPORTS := 1