Make translation units in the same CompileReq visible to `import`. (#2184)

* Make translation unitts in the same CompileReq visible to `import`.

* Fix code review comments.

Co-authored-by: Yong He <yhe@nvidia.com>
Co-authored-by: Theresa Foley <10618364+tangent-vector@users.noreply.github.com>

2 files changed, 60 insertions, 1 deletions

diff --git a/tools/slang-unit-test/unit-test-find-type-by-name.cpp b/tools/slang-unit-test/unit-test-find-type-by-name.cpp
index d12a0d91f..87be156db 100644
--- a/tools/slang-unit-test/unit-test-find-type-by-name.cpp
+++ b/tools/slang-unit-test/unit-test-find-type-by-name.cpp
@@ -1,4 +1,4 @@
-// unit-test-byte-encode.cpp
+// unit-test-find-type-by-name.cpp
 
 #include "../../slang.h"
 
diff --git a/tools/slang-unit-test/unit-test-translation-unit-import.cpp b/tools/slang-unit-test/unit-test-translation-unit-import.cpp
new file mode 100644
index 000000000..dfa75eb9f
--- /dev/null
+++ b/tools/slang-unit-test/unit-test-translation-unit-import.cpp
@@ -0,0 +1,59 @@
+// unit-test-translation-unit-import.cpp
+
+#include "../../slang.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "tools/unit-test/slang-unit-test.h"
+#include "../../slang-com-ptr.h"
+
+using namespace Slang;
+
+// Test that the API supports discovering previously checked translation unit in the same
+// FrontEndCompileRequest.
+SLANG_UNIT_TEST(translationUnitImport)
+{
+    // Source for the first translation unit.
+    const char* generatedSource =
+        "int f() {"
+        "   return 5;"
+        "};";
+
+    // Source for the second translation unit that imports the first translation unit.
+    // The import should succeed and `f` should be visible to this module.
+    const char* userSource =
+        R"(
+        import generatedUnit;
+
+        [shader("compute")]
+        [numthreads(4,1,1)]
+        void computeMain(
+            uint3 sv_dispatchThreadID : SV_DispatchThreadID,
+            uniform RWStructuredBuffer<int> buffer)
+        {
+            buffer[sv_dispatchThreadID.x] = f();
+        }
+        )";    
+    auto session = spCreateSession();
+    auto request = spCreateCompileRequest(session);
+    spAddCodeGenTarget(request, SLANG_HLSL);
+    int generatedTranslationUnitIndex = spAddTranslationUnit(request, SLANG_SOURCE_LANGUAGE_SLANG, "generatedUnit");
+    spAddTranslationUnitSourceString(
+        request, generatedTranslationUnitIndex, "generatedFile", generatedSource);
+    int entryPointTranslationUnitIndex = spAddTranslationUnit(request, SLANG_SOURCE_LANGUAGE_SLANG, "userUnit");
+    spAddTranslationUnitSourceString(
+        request, entryPointTranslationUnitIndex, "userFile", userSource);
+    spAddEntryPoint(request, entryPointTranslationUnitIndex, "computeMain", SLANG_STAGE_COMPUTE);
+
+    auto compileResult = spCompile(request);
+    SLANG_CHECK(compileResult == SLANG_OK);
+
+    Slang::ComPtr<ISlangBlob> outBlob;
+    spGetEntryPointCodeBlob(request, 0, 0, outBlob.writeRef());
+    SLANG_CHECK(outBlob && outBlob->getBufferSize() != 0);
+
+    spDestroyCompileRequest(request);
+    spDestroySession(session);
+}
+