From 78a206201251470e441b452f7e2cb078ef382073 Mon Sep 17 00:00:00 2001
From: Erich Keane <erich.keane@intel.com>
Date: Tue, 2 Mar 2021 06:32:58 -0800
Subject: [PATCH 1/3] [SYCL] Fix a crash with __bulitin_unique_stable_name

A placeholder expression inside a unique-stable-name(at this point, an
unresolved lookup expression) was not properly being transformed during
template instantation.  This patch ensures that it gets instantiated.
---
 clang/lib/Sema/SemaTemplateInstantiate.cpp    |  6 ++++
 .../unique-stable-name-placeholder-crash.cpp  | 29 +++++++++++++++++++
 2 files changed, 35 insertions(+)
 create mode 100644 clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp

diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index 491d77c7dc502..e256830ac455a 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1460,6 +1460,12 @@ static ExprResult TransformUniqueStableName(TemplateInstantiator &TI,
     if (SubExpr.isInvalid())
       return ExprError();
 
+    SubExpr = TI.getSema().CheckPlaceholderExpr(SubExpr.get());
+
+    if (SubExpr.isInvalid())
+      return ExprError();
+
+
     if (!TI.getDerived().AlwaysRebuild() && SubExpr.get() == E->getExpr())
       return E;
 
diff --git a/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp b/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp
new file mode 100644
index 0000000000000..5b11afa467858
--- /dev/null
+++ b/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple spir64-unknown-unknown-sycldevice -std=c++17 -sycl-std=2020 -fsycl -fsycl-is-device -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s
+
+template <typename KernelName, typename KernelType>
+[[clang::sycl_kernel]] void kernel_single_task(const KernelType &kernelFunc) {
+  kernelFunc();
+}
+
+struct A {
+  int a = 0;
+  A() = default;
+};
+constexpr A THE_NAME;
+
+template <auto &R> void temp() {}
+template <auto &R> void foo(const char *out) {
+  out = __builtin_unique_stable_name(temp<R>);
+}
+
+int main() {
+  kernel_single_task<class kernel>(
+      []() {
+        const char *c;
+        foo<THE_NAME>(c);
+      });
+}
+
+// Note: the mangling here is actually the 'typeinfo name for void ()'.  That is
+// because the type of temp<R> is actually the function type (which is void()).
+// CHECK: @__builtin_unique_stable_name._Z3fooIL_ZL8THE_NAMEEEvPKc = private unnamed_addr addrspace(1) constant [9 x i8] c"_ZTSFvvE\00", align 1

From 0d4af0b17e2f273b18372221516d8acf2bc71983 Mon Sep 17 00:00:00 2001
From: Erich Keane <erich.keane@intel.com>
Date: Tue, 2 Mar 2021 06:36:29 -0800
Subject: [PATCH 2/3] remove extranious newline

---
 clang/lib/Sema/SemaTemplateInstantiate.cpp | 1 -
 1 file changed, 1 deletion(-)

diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp
index e256830ac455a..e59200cfdd657 100644
--- a/clang/lib/Sema/SemaTemplateInstantiate.cpp
+++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp
@@ -1465,7 +1465,6 @@ static ExprResult TransformUniqueStableName(TemplateInstantiator &TI,
     if (SubExpr.isInvalid())
       return ExprError();
 
-
     if (!TI.getDerived().AlwaysRebuild() && SubExpr.get() == E->getExpr())
       return E;
 

From b9086a4b1e463e3ea0933d5def0efd0b285ac088 Mon Sep 17 00:00:00 2001
From: Erich Keane <erich.keane@intel.com>
Date: Tue, 2 Mar 2021 07:50:28 -0800
Subject: [PATCH 3/3] Change to use the mock header

---
 .../CodeGenSYCL/unique-stable-name-placeholder-crash.cpp | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp b/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp
index 5b11afa467858..ba28e35ae00af 100644
--- a/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp
+++ b/clang/test/CodeGenSYCL/unique-stable-name-placeholder-crash.cpp
@@ -1,9 +1,8 @@
-// RUN: %clang_cc1 -triple spir64-unknown-unknown-sycldevice -std=c++17 -sycl-std=2020 -fsycl -fsycl-is-device -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple spir64-unknown-unknown-sycldevice -internal-isystem %S/Inputs -std=c++17 -sycl-std=2020 -fsycl -fsycl-is-device -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s
 
-template <typename KernelName, typename KernelType>
-[[clang::sycl_kernel]] void kernel_single_task(const KernelType &kernelFunc) {
-  kernelFunc();
-}
+#include <sycl.hpp>
+
+using namespace cl::sycl;
 
 struct A {
   int a = 0;