From 3809395c080a8b2aa4e3ddcd3998c04798f859d0 Mon Sep 17 00:00:00 2001
From: Ehsan <ehsann@google.com>
Date: Mon, 20 Nov 2017 08:46:07 -0500
Subject: [PATCH] [spirv] Support CXXDefaultArgExpr translation. (#825)

---
 tools/clang/lib/SPIRV/SPIRVEmitter.cpp        |  4 +++
 .../test/CodeGenSPIRV/fn.default-arg.hlsl     | 28 +++++++++++++++++++
 .../unittests/SPIRV/CodeGenSPIRVTest.cpp      |  1 +
 3 files changed, 33 insertions(+)
 create mode 100644 tools/clang/test/CodeGenSPIRV/fn.default-arg.hlsl

diff --git a/tools/clang/lib/SPIRV/SPIRVEmitter.cpp b/tools/clang/lib/SPIRV/SPIRVEmitter.cpp
index b54a68f9d..f0bfbcbb6 100644
--- a/tools/clang/lib/SPIRV/SPIRVEmitter.cpp
+++ b/tools/clang/lib/SPIRV/SPIRVEmitter.cpp
@@ -509,6 +509,10 @@ SpirvEvalInfo SPIRVEmitter::doExpr(const Expr *expr) {
     return doConditionalOperator(condExpr);
   }
 
+  if (const auto *defaultArgExpr = dyn_cast<CXXDefaultArgExpr>(expr)) {
+    return doExpr(defaultArgExpr->getParam()->getDefaultArg());
+  }
+
   if (isa<CXXThisExpr>(expr)) {
     assert(curThis);
     return curThis;
diff --git a/tools/clang/test/CodeGenSPIRV/fn.default-arg.hlsl b/tools/clang/test/CodeGenSPIRV/fn.default-arg.hlsl
new file mode 100644
index 000000000..5b8d42b78
--- /dev/null
+++ b/tools/clang/test/CodeGenSPIRV/fn.default-arg.hlsl
@@ -0,0 +1,28 @@
+// Run: %dxc -T vs_6_0 -E main
+
+int foo(int x = 5)
+{
+  return x + 1;
+}
+
+void main()
+{
+// CHECK:      %param_var_x = OpVariable %_ptr_Function_int Function
+// CHECK-NEXT: %param_var_x_0 = OpVariable %_ptr_Function_int Function
+// CHECK-NEXT: %param_var_x_1 = OpVariable %_ptr_Function_int Function
+
+// CHECK-NEXT: OpStore %param_var_x %int_5
+// CHECK-NEXT: {{%\d+}} = OpFunctionCall %int %foo %param_var_x
+  // Call without passing arg.
+  foo();
+
+// CHECK-NEXT: OpStore %param_var_x_0 %int_2
+// CHECK-NEXT: {{%\d+}} = OpFunctionCall %int %foo %param_var_x_0
+  // Call with passing arg.
+  foo(2);
+
+// CHECK-NEXT: OpStore %param_var_x_1 %int_5
+// CHECK-NEXT: {{%\d+}} = OpFunctionCall %int %foo %param_var_x_1
+  // Call without passing arg again.
+  foo();
+}
diff --git a/tools/clang/unittests/SPIRV/CodeGenSPIRVTest.cpp b/tools/clang/unittests/SPIRV/CodeGenSPIRVTest.cpp
index 02cef823d..1aab18993 100644
--- a/tools/clang/unittests/SPIRV/CodeGenSPIRVTest.cpp
+++ b/tools/clang/unittests/SPIRV/CodeGenSPIRVTest.cpp
@@ -354,6 +354,7 @@ TEST_F(FileTest, ControlFlowConditionalOp) { runFileTest("cf.cond-op.hlsl"); }
 
 // For functions
 TEST_F(FileTest, FunctionCall) { runFileTest("fn.call.hlsl"); }
+TEST_F(FileTest, FunctionDefaultArg) { runFileTest("fn.default-arg.hlsl"); }
 TEST_F(FileTest, FunctionInOutParam) { runFileTest("fn.param.inout.hlsl"); }
 
 // For OO features