Don't demangle Rust symbols by default, but allow linking to rust-demangle.

The Rust compiler uses GCC C++ name mangling, but it has another layer of
encoding so abi::cxa_demangle doesn't produce great results. This patch
changes dump_syms to dump unmangled names by default so that consumers can
demangle them after-the-fact.

It also adds a tiny bit of support for linking against a Rust library I wrote
that can demangle Rust symbols nicely:
https://github.com/luser/rust-demangle-capi

BUG=

Change-Id: I63a425035ebb7ac516f067fed2aa782849ea9604
Reviewed-on: https://chromium-review.googlesource.com/402308
Reviewed-by: Mark Mentovai <mark@chromium.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/src/common/dwarf_cu_to_module_unittest.cc b/src/common/dwarf_cu_to_module_unittest.cc
index e789f9da..2ce4a609 100644
--- a/src/common/dwarf_cu_to_module_unittest.cc
+++ b/src/common/dwarf_cu_to_module_unittest.cc
@@ -1205,6 +1205,7 @@ TEST_F(Specifications, Function) {
 }
 
 TEST_F(Specifications, MangledName) {
+  // Language defaults to C++, so no need to set it here.
   PushLine(0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL, "line-file", 54883661);
 
   StartCU();
@@ -1221,6 +1222,53 @@ TEST_F(Specifications, MangledName) {
                0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL);
 }
 
+TEST_F(Specifications, MangledNameSwift) {
+  // Swift mangled names should pass through untouched.
+  SetLanguage(dwarf2reader::DW_LANG_Swift);
+  PushLine(0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL, "line-file", 54883661);
+  StartCU();
+  const string kName = "_TFC9swifttest5Shape17simpleDescriptionfS0_FT_Si";
+  DeclarationDIE(&root_handler_, 0xcd3c51b946fb1eeeLL,
+                 dwarf2reader::DW_TAG_subprogram, "declaration-name",
+                 kName);
+  DefinitionDIE(&root_handler_, dwarf2reader::DW_TAG_subprogram,
+                0xcd3c51b946fb1eeeLL, "",
+                0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL);
+  root_handler_.Finish();
+
+  TestFunctionCount(1);
+  TestFunction(0, kName,
+               0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL);
+}
+
+TEST_F(Specifications, MangledNameRust) {
+  SetLanguage(dwarf2reader::DW_LANG_Rust);
+  PushLine(0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL, "line-file", 54883661);
+
+  StartCU();
+  const string kName = "_ZN14rustc_demangle8demangle17h373defa94bffacdeE";
+  DeclarationDIE(&root_handler_, 0xcd3c51b946fb1eeeLL,
+                 dwarf2reader::DW_TAG_subprogram, "declaration-name",
+                 kName);
+  DefinitionDIE(&root_handler_, dwarf2reader::DW_TAG_subprogram,
+                0xcd3c51b946fb1eeeLL, "",
+                0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL);
+  root_handler_.Finish();
+
+  TestFunctionCount(1);
+  TestFunction(0,
+#ifndef HAVE_RUST_DEMANGLE
+               // Rust mangled names should pass through untouched if not
+               // using rust-demangle.
+               kName,
+#else
+               // If rust-demangle is available this should be properly
+               // demangled.
+               "rustc_demangle::demangle",
+#endif
+               0x93cd3dfc1aa10097ULL, 0x0397d47a0b4ca0d4ULL);
+}
+
 TEST_F(Specifications, MemberFunction) {
   PushLine(0x3341a248634e7170ULL, 0x5f6938ee5553b953ULL, "line-file", 18116691);