From d19c9eb32be42a01a2991a3289675dbdca943595 Mon Sep 17 00:00:00 2001
From: Egor Zhdan <e_zhdan@apple.com>
Date: Wed, 4 Sep 2024 14:37:44 +0100
Subject: [PATCH] [cxx-interop] Disambiguate template instantiations with SIMD
 parameters

When converting a C++ class template instantiation name into Swift, we previously didn't account for possible SIMD types. Those types were printed as `_`. This meant that e.g. `std::vector<simd::float3>` and `std::vector<simd::float4>` would get the same Swift name, causing compiler errors down the road.

rdar://134214091
---
 lib/ClangImporter/ClangClassTemplateNamePrinter.cpp  |  6 ++++++
 .../Inputs/class-template-with-simd-parameter.h      | 12 ++++++++++++
 test/Interop/Cxx/templates/Inputs/module.modulemap   |  5 +++++
 ...mplate-with-simd-parameter-module-interface.swift |  9 +++++++++
 4 files changed, 32 insertions(+)
 create mode 100644 test/Interop/Cxx/templates/Inputs/class-template-with-simd-parameter.h
 create mode 100644 test/Interop/Cxx/templates/class-template-with-simd-parameter-module-interface.swift

diff --git a/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp b/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
index fad5d3dc73254..19fad0fea8050 100644
--- a/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
+++ b/lib/ClangImporter/ClangClassTemplateNamePrinter.cpp
@@ -129,6 +129,12 @@ struct TemplateInstantiationNamePrinter
 
     return buffer.str().str();
   }
+
+  std::string VisitVectorType(const clang::VectorType *type) {
+    return (Twine("SIMD") + std::to_string(type->getNumElements()) + "<" +
+            Visit(type->getElementType().getTypePtr()) + ">")
+        .str();
+  }
 };
 
 std::string swift::importer::printClassTemplateSpecializationName(
diff --git a/test/Interop/Cxx/templates/Inputs/class-template-with-simd-parameter.h b/test/Interop/Cxx/templates/Inputs/class-template-with-simd-parameter.h
new file mode 100644
index 0000000000000..3e879a33f21f6
--- /dev/null
+++ b/test/Interop/Cxx/templates/Inputs/class-template-with-simd-parameter.h
@@ -0,0 +1,12 @@
+#include <simd/simd.h>
+
+template <typename T>
+struct Templated {
+  T t;
+};
+
+typedef Templated<simd::uint1> TemplatedSIMDUInt1;
+typedef Templated<simd::uint16> TemplatedSIMDUInt16;
+typedef Templated<simd::float3> TemplatedSIMDFloat3;
+typedef Templated<simd::float4> TemplatedSIMDFloat4;
+typedef Templated<simd::double8> TemplatedSIMDDouble8;
diff --git a/test/Interop/Cxx/templates/Inputs/module.modulemap b/test/Interop/Cxx/templates/Inputs/module.modulemap
index a7fc0b8fbbd99..8fbcea80b696e 100644
--- a/test/Interop/Cxx/templates/Inputs/module.modulemap
+++ b/test/Interop/Cxx/templates/Inputs/module.modulemap
@@ -18,6 +18,11 @@ module ClassTemplateWithOutOfLineMember {
   requires cplusplus
 }
 
+module ClassTemplateWithSIMDParameter {
+  header "class-template-with-simd-parameter.h"
+  requires cplusplus
+}
+
 module NotPreDefinedClassTemplate {
   header "not-pre-defined-class-template.h"
   requires cplusplus
diff --git a/test/Interop/Cxx/templates/class-template-with-simd-parameter-module-interface.swift b/test/Interop/Cxx/templates/class-template-with-simd-parameter-module-interface.swift
new file mode 100644
index 0000000000000..7c300ab6c5748
--- /dev/null
+++ b/test/Interop/Cxx/templates/class-template-with-simd-parameter-module-interface.swift
@@ -0,0 +1,9 @@
+// RUN: %target-swift-ide-test -print-module -module-to-print=ClassTemplateWithSIMDParameter -I %S/Inputs -source-filename=x -cxx-interoperability-mode=upcoming-swift | %FileCheck %s
+
+// REQUIRES: OS=macosx || OS=ios
+
+// CHECK: typealias TemplatedSIMDUInt1 = Templated<CUnsignedInt>
+// CHECK: typealias TemplatedSIMDUInt16 = Templated<SIMD16<CUnsignedInt>>
+// CHECK: typealias TemplatedSIMDFloat3 = Templated<SIMD3<CFloat>>
+// CHECK: typealias TemplatedSIMDFloat4 = Templated<SIMD4<CFloat>>
+// CHECK: typealias TemplatedSIMDDouble8 = Templated<SIMD8<CDouble>>