[Demangle][Rust] Parse dot suffix

Allow mangled names to include an arbitrary dot suffix, akin to vendor
specific suffix in Itanium mangling.

Primary motivation is a support for symbols renamed during ThinLTO
import / promotion (ThinLTO is the default configuration for optimized
builds in rustc).

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D104358

1 files changed, 9 insertions, 1 deletions

diff --git a/llvm/lib/Demangle/RustDemangle.cpp b/llvm/lib/Demangle/RustDemangle.cpp
index 919a668..39db8fd 100644
--- a/llvm/lib/Demangle/RustDemangle.cpp
+++ b/llvm/lib/Demangle/RustDemangle.cpp
@@ -109,7 +109,9 @@ bool Demangler::demangle(StringView Mangled) {
     Error = true;
     return false;
   }
-  Input = Mangled;
+  size_t Dot = Mangled.find('.');
+  Input = Mangled.substr(0, Dot);
+  StringView Suffix = Mangled.dropFront(Dot);
 
   demanglePath(rust_demangle::InType::No);
 
@@ -121,6 +123,12 @@ bool Demangler::demangle(StringView Mangled) {
   if (Position != Input.size())
     Error = true;
 
+  if (!Suffix.empty()) {
+    print(" (");
+    print(Suffix);
+    print(")");
+  }
+
   return !Error;
 }