Add reflection api for overload candidate filtering. (#8066)

* Add reflection api for overload candidate filtering.

* Fix API.

* Fix.

* Update build.

* Update test.

* Update formatting.

2 files changed, 94 insertions, 1 deletions

diff --git a/tools/CMakeLists.txt b/tools/CMakeLists.txt
index 00bd93c49..7b28e960f 100644
--- a/tools/CMakeLists.txt
+++ b/tools/CMakeLists.txt
@@ -377,7 +377,9 @@ if(SLANG_ENABLE_TESTS)
         slang-unit-test
         MODULE
         EXCLUDE_FROM_ALL
-        EXTRA_COMPILE_DEFINITIONS_PRIVATE SLANG_SHARED_LIBRARY_TOOL
+        EXTRA_COMPILE_DEFINITIONS_PRIVATE
+            SLANG_SHARED_LIBRARY_TOOL
+            SLANG_NO_DEPRECATION
         USE_FEWER_WARNINGS
         LINK_WITH_PRIVATE core compiler-core unit-test slang Threads::Threads
         OUTPUT_NAME slang-unit-test-tool
diff --git a/tools/slang-unit-test/unit-test-function-lookup-resolution.cpp b/tools/slang-unit-test/unit-test-function-lookup-resolution.cpp
new file mode 100644
index 000000000..539c9ac48
--- /dev/null
+++ b/tools/slang-unit-test/unit-test-function-lookup-resolution.cpp
@@ -0,0 +1,91 @@
+// unit-test-function-lookup-resolution.cpp
+
+#include "../../source/core/slang-io.h"
+#include "../../source/core/slang-process.h"
+#include "slang-com-ptr.h"
+#include "slang.h"
+#include "unit-test/slang-unit-test.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+using namespace Slang;
+
+static String getTypeFullName(slang::TypeReflection* type)
+{
+    ComPtr<ISlangBlob> blob;
+    type->getFullName(blob.writeRef());
+    return String((const char*)blob->getBufferPointer());
+}
+
+// Test that the reflection API provides correctly resolved lookup results.
+
+SLANG_UNIT_TEST(functionLookupResolution)
+{
+    // Source for a module that contains an undecorated entrypoint.
+    const char* userSourceBody = R"(
+        public interface IBase
+        {
+            public void step(inout float f);
+            public void method(int x) {}
+        }
+
+        public struct Impl : IBase
+        {
+            public void step(inout float f)
+            {
+                f += 1.0f;
+            }
+            public override void method(int x) {}
+        }
+        public extension<T : IBase> T {
+            public void method(int x) {}
+        }
+        )";
+
+    auto moduleName = "moduleG" + String(Process::getId());
+    String userSource = "import " + moduleName + ";\n" + userSourceBody;
+    ComPtr<slang::IGlobalSession> globalSession;
+    SLANG_CHECK(slang_createGlobalSession(SLANG_API_VERSION, globalSession.writeRef()) == SLANG_OK);
+    slang::TargetDesc targetDesc = {};
+    targetDesc.format = SLANG_HLSL;
+    targetDesc.profile = globalSession->findProfile("sm_5_0");
+    slang::SessionDesc sessionDesc = {};
+    sessionDesc.targetCount = 1;
+    sessionDesc.targets = &targetDesc;
+    ComPtr<slang::ISession> session;
+    SLANG_CHECK(globalSession->createSession(sessionDesc, session.writeRef()) == SLANG_OK);
+
+    ComPtr<slang::IBlob> diagnosticBlob;
+    auto module = session->loadModuleFromSourceString(
+        "m",
+        "m.slang",
+        userSourceBody,
+        diagnosticBlob.writeRef());
+    SLANG_CHECK(module != nullptr);
+
+    auto layout = module->getLayout();
+    auto type = layout->findTypeByName("Impl");
+    SLANG_CHECK_ABORT(type != nullptr);
+
+    auto func = layout->findFunctionByNameInType(type, "step");
+    SLANG_CHECK_ABORT(func && !func->isOverloaded());
+
+
+    auto func1 = layout->findFunctionByNameInType(type, "method");
+    SLANG_CHECK_ABORT(func1->isOverloaded());
+    SLANG_CHECK(func1->getOverloadCount() == 3);
+    if (func1->isOverloaded())
+    {
+        List<slang::FunctionReflection*> candidates;
+        for (uint32_t i = 0; i < func1->getOverloadCount(); i++)
+        {
+            candidates.add(func1->getOverload(i));
+        }
+        func1 = layout->tryResolveOverloadedFunction(
+            (uint32_t)candidates.getCount(),
+            candidates.getBuffer());
+    }
+    SLANG_CHECK(!func1->isOverloaded());
+    SLANG_CHECK(String(func1->getName()) == "method");
+}