5 files changed, 113 insertions, 4 deletions
diff --git a/llvm/test/tools/dsymutil/basic-linking.test b/llvm/test/tools/dsymutil/basic-linking.test
new file mode 100644
index 00000000000..adbd595c457
--- /dev/null
+++ b/llvm/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
+
diff --git a/llvm/tools/dsymutil/CMakeLists.txt b/llvm/tools/dsymutil/CMakeLists.txt
index bfe7c706391..c397e3ed36c 100644
--- a/llvm/tools/dsymutil/CMakeLists.txt
+++ b/llvm/tools/dsymutil/CMakeLists.txt
@@ -1,4 +1,5 @@
 set(LLVM_LINK_COMPONENTS
+  DebugInfo
   Object
   Support
   )
diff --git a/llvm/tools/dsymutil/DwarfLinker.cpp b/llvm/tools/dsymutil/DwarfLinker.cpp
index ad471055bd9..4af8efb03af 100644
--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/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);
+}
+}
 }
diff --git a/llvm/tools/dsymutil/LLVMBuild.txt b/llvm/tools/dsymutil/LLVMBuild.txt
index 24b9033c78c..dd9151e2b9a 100644
--- a/llvm/tools/dsymutil/LLVMBuild.txt
+++ b/llvm/tools/dsymutil/LLVMBuild.txt
@@ -19,4 +19,4 @@
 type = Tool
 name = llvm-dsymutil
 parent = Tools
-required_libraries = Object Support
+required_libraries = DebugInfo Object Support
diff --git a/llvm/tools/dsymutil/Makefile b/llvm/tools/dsymutil/Makefile
index 9eda7dcabc0..fd437aa2ce3 100644
--- a/llvm/tools/dsymutil/Makefile
+++ b/llvm/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