From 67f4a371e5a928839f8d8cb016e69e428aeb874f Mon Sep 17 00:00:00 2001
From: Philip Herron <philip.herron@embecosm.com>
Date: Wed, 24 Nov 2021 19:55:09 +0000
Subject: Update legacy mangling of names

In rust the mangling of names needs to handle cases such as qualified paths
<&mut T as Deref>::deref. Assemblers cannot handle '&' and whitespace
otherwise we will fail to assemble the functions, the legacy mangling
scheme turns all reference's '&' into 'RF' and all whitespace into '$'
this means we can mangle more complex canonical paths. Which are needed
in order to support the deref operator overloading.
---
 gcc/rust/backend/rust-mangle.cc | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

(limited to 'gcc/rust/backend')

diff --git a/gcc/rust/backend/rust-mangle.cc b/gcc/rust/backend/rust-mangle.cc
index 15ac3b1..d0fec0d 100644
--- a/gcc/rust/backend/rust-mangle.cc
+++ b/gcc/rust/backend/rust-mangle.cc
@@ -18,7 +18,26 @@ Mangler::MangleVersion Mangler::version = MangleVersion::LEGACY;
 static std::string
 legacy_mangle_name (const std::string &name)
 {
-  return std::to_string (name.size ()) + name;
+  // example
+  //  <&T as core::fmt::Debug>::fmt:
+  //  _ZN42_$LT$$RF$T$u20$as$u20$core..fmt..Debug$GT$3fmt17h6dac924c0051eef7E
+  // replace all white space with $ and & with RF
+
+  std::string buffer;
+  for (const auto &c : name)
+    {
+      std::string m;
+      if (c == ' ')
+	m = "$";
+      else if (c == '&')
+	m = "RF";
+      else
+	m.push_back (c);
+
+      buffer += m;
+    }
+
+  return std::to_string (buffer.size ()) + buffer;
 }
 
 static std::string
-- 
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