From ecc5a39feecbf73feedf352214406c8752af798a Mon Sep 17 00:00:00 2001
From: Darren Wihandi <65404740+fairywreath@users.noreply.github.com>
Date: Thu, 5 Dec 2024 20:09:40 -0500
Subject: Do recursive function checks early during IR linking (#5777)

---
 source/slang/slang-ir-check-recursion.cpp | 126 ++++++++++++++++++++++++++++++
 1 file changed, 126 insertions(+)
 create mode 100644 source/slang/slang-ir-check-recursion.cpp

(limited to 'source/slang/slang-ir-check-recursion.cpp')

diff --git a/source/slang/slang-ir-check-recursion.cpp b/source/slang/slang-ir-check-recursion.cpp
new file mode 100644
index 000000000..404437a46
--- /dev/null
+++ b/source/slang/slang-ir-check-recursion.cpp
@@ -0,0 +1,126 @@
+#include "slang-ir-check-recursion.h"
+
+#include "slang-ir-util.h"
+
+namespace Slang
+{
+bool checkTypeRecursionImpl(
+    HashSet<IRInst*>& checkedTypes,
+    HashSet<IRInst*>& stack,
+    IRInst* type,
+    IRInst* field,
+    DiagnosticSink* sink)
+{
+    auto visitElementType = [&](IRInst* elementType, IRInst* field) -> bool
+    {
+        if (!stack.add(elementType))
+        {
+            sink->diagnose(field ? field : type, Diagnostics::recursiveType, type);
+            return false;
+        }
+        if (checkedTypes.add(elementType))
+            checkTypeRecursionImpl(checkedTypes, stack, elementType, field, sink);
+        stack.remove(elementType);
+        return true;
+    };
+    if (auto arrayType = as<IRArrayTypeBase>(type))
+    {
+        return visitElementType(arrayType->getElementType(), field);
+    }
+    else if (auto structType = as<IRStructType>(type))
+    {
+        for (auto sfield : structType->getFields())
+            if (!visitElementType(sfield->getFieldType(), sfield))
+                return false;
+    }
+    return true;
+}
+
+void checkTypeRecursion(HashSet<IRInst*>& checkedTypes, IRInst* type, DiagnosticSink* sink)
+{
+    HashSet<IRInst*> stack;
+    if (checkedTypes.add(type))
+    {
+        stack.add(type);
+        checkTypeRecursionImpl(checkedTypes, stack, type, nullptr, sink);
+    }
+}
+
+void checkForRecursiveTypes(IRModule* module, DiagnosticSink* sink)
+{
+    HashSet<IRInst*> checkedTypes;
+    for (auto globalInst : module->getGlobalInsts())
+    {
+        switch (globalInst->getOp())
+        {
+        case kIROp_StructType:
+            {
+                checkTypeRecursion(checkedTypes, globalInst, sink);
+            }
+            break;
+        default:
+            break;
+        }
+    }
+}
+
+bool checkFunctionRecursionImpl(
+    HashSet<IRFunc*>& checkedFuncs,
+    HashSet<IRFunc*>& callStack,
+    IRFunc* func,
+    DiagnosticSink* sink)
+{
+    for (auto block : func->getBlocks())
+    {
+        for (auto inst : block->getChildren())
+        {
+            auto callInst = as<IRCall>(inst);
+            if (!callInst)
+                continue;
+            auto callee = as<IRFunc>(callInst->getCallee());
+            if (!callee)
+                continue;
+            if (!callStack.add(callee))
+            {
+                sink->diagnose(callInst, Diagnostics::unsupportedRecursion, callee);
+                return false;
+            }
+            if (checkedFuncs.add(callee))
+                checkFunctionRecursionImpl(checkedFuncs, callStack, callee, sink);
+            callStack.remove(callee);
+        }
+    }
+    return true;
+}
+
+void checkFunctionRecursion(HashSet<IRFunc*>& checkedFuncs, IRFunc* func, DiagnosticSink* sink)
+{
+    HashSet<IRFunc*> callStack;
+    if (checkedFuncs.add(func))
+    {
+        callStack.add(func);
+        checkFunctionRecursionImpl(checkedFuncs, callStack, func, sink);
+    }
+}
+
+void checkForRecursiveFunctions(TargetRequest* target, IRModule* module, DiagnosticSink* sink)
+{
+    HashSet<IRFunc*> checkedFuncsForRecursionDetection;
+    for (auto globalInst : module->getGlobalInsts())
+    {
+        switch (globalInst->getOp())
+        {
+        case kIROp_Func:
+            if (!isCPUTarget(target))
+                checkFunctionRecursion(
+                    checkedFuncsForRecursionDetection,
+                    as<IRFunc>(globalInst),
+                    sink);
+            break;
+        default:
+            break;
+        }
+    }
+}
+
+} // namespace Slang
-- 
cgit v1.2.3