File llvm-rust-mangle-for-fastcall.patch of Package llvm13

From 54b909de682bfa4e3389b680b0916ab18c99952a Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Fri, 25 Feb 2022 22:06:47 +0000
Subject: [PATCH] [Mangler] Mangle aliases to fastcall/vectorcall functions
 correctly

These aliases are produced by MergeFunctions and need to be mangled according to the calling convention of the function they are pointing to instead of defaulting to the C calling convention.

Reviewed By: rnk

Differential Revision: https://reviews.llvm.org/D120382
---
 llvm/lib/IR/Mangler.cpp                            | 2 +-
 llvm/test/CodeGen/X86/fastcall-correct-mangling.ll | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/IR/Mangler.cpp b/llvm/lib/IR/Mangler.cpp
index 2399ea27ee9d4..b8e3e40e4c1d5 100644
--- a/llvm/lib/IR/Mangler.cpp
+++ b/llvm/lib/IR/Mangler.cpp
@@ -144,7 +144,7 @@ void Mangler::getNameWithPrefix(raw_ostream &OS, const GlobalValue *GV,
 
   // Mangle functions with Microsoft calling conventions specially.  Only do
   // this mangling for x86_64 vectorcall and 32-bit x86.
-  const Function *MSFunc = dyn_cast<Function>(GV);
+  const Function *MSFunc = dyn_cast_or_null<Function>(GV->getBaseObject());
 
   // Don't add byte count suffixes when '\01' or '?' are in the first
   // character.
diff --git a/llvm/test/CodeGen/X86/fastcall-correct-mangling.ll b/llvm/test/CodeGen/X86/fastcall-correct-mangling.ll
index 00dc44e75e8f5..dd8ce0f0ef505 100644
--- a/llvm/test/CodeGen/X86/fastcall-correct-mangling.ll
+++ b/llvm/test/CodeGen/X86/fastcall-correct-mangling.ll
@@ -31,3 +31,7 @@ define private x86_fastcallcc void @dontCrash() {
 ; CHECK64-LABEL: {{^}}.LdontCrash:
   ret void
 }
+
+@alias = alias void(i64, i8, i8, i16), void(i64, i8, i8, i16)* @func
+; CHECK32-LABEL: {{^}}.set @alias@20, @func@20
+; CHECK64-LABEL: {{^}}.set alias, func