Initial support for dumping DWARF corresponding to Swift code

src/common/dwarf_cu_to_module.cc

Index: src/common/dwarf_cu_to_module.cc
diff --git a/src/common/dwarf_cu_to_module.cc b/src/common/dwarf_cu_to_module.cc
index 479e39b221250bf37a84cbd8ecdbb652825757e6..bcda18afb2ff97a6b17c7e4dab7e7f3eb6cfe4ec 100644
--- a/src/common/dwarf_cu_to_module.cc
+++ b/src/common/dwarf_cu_to_module.cc
@@ -39,9 +39,6 @@
 #include "common/dwarf_cu_to_module.h"
 
 #include <assert.h>
-#if !defined(__ANDROID__)
-#include <cxxabi.h>
-#endif
 #include <inttypes.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -350,20 +347,18 @@ void DwarfCUToModule::GenericDIEHandler::ProcessAttributeString(
     case dwarf2reader::DW_AT_name:
       name_attribute_ = AddStringToPool(data);
       break;
-    case dwarf2reader::DW_AT_MIPS_linkage_name: {
-      char* demangled = NULL;
-      int status = -1;
-#if !defined(__ANDROID__)  // Android NDK doesn't provide abi::__cxa_demangle.
-      demangled = abi::__cxa_demangle(data.c_str(), NULL, NULL, &status);
-#endif
+    case dwarf2reader::DW_AT_MIPS_linkage_name:
+    case dwarf2reader::DW_AT_linkage_name: {
+      string demangled;
+      int status = cu_context_->language->DemangleName(data,
+                                                       &demangled);
       if (status != 0) {
-        cu_context_->reporter->DemangleError(data, status);
-        demangled_name_ = "";
-        break;
-      }
-      if (demangled) {
+        if (status != Language::kDontDemangle) {

[Ted Mielczarek, 2016/09/14 10:20:10]

It's unfortunate that we lose the language context here when we translate to
.sym format. It would be nice to be able to demangle reliably instead of having
to guess. (I suppose it's not that hard to guess, though, given the mangled
symbol prefix.)

[Mark Mentovai, 2016/09/21 17:56:55]

Ted Mielczarek wrote:
In the future, maybe we can spin up a pipe to swift-demangle to get these in
dump_syms instead of relying on post-processing. That’d still only work if
swift-demangle was available, but it’s something…

+          cu_context_->reporter->DemangleError(data, status);
+        }
+        demangled_name_.clear();
+      } else {
         demangled_name_ = AddStringToPool(demangled);
-        free(reinterpret_cast<void*>(demangled));
       }
       break;
     }
@@ -761,6 +756,7 @@ dwarf2reader::DIEHandler *DwarfCUToModule::FindChildHandler(
     case dwarf2reader::DW_TAG_class_type:
     case dwarf2reader::DW_TAG_structure_type:
     case dwarf2reader::DW_TAG_union_type:
+    case dwarf2reader::DW_TAG_module:
       return new NamedScopeHandler(cu_context_.get(), child_context_.get(),
                                    offset);
     default:
@@ -774,6 +770,10 @@ void DwarfCUToModule::SetLanguage(DwarfLanguage language) {
       cu_context_->language = Language::Java;
       break;
 
+    case dwarf2reader::DW_LANG_Swift:
+      cu_context_->language = Language::Swift;
+      break;
+
     // DWARF has no generic language code for assembly language; this is
     // what the GNU toolchain uses.
     case dwarf2reader::DW_LANG_Mips_Assembler: