Ignoring constructors

source/slang/slang-ir-use-uninitialized-values.cpp

@@ -8,6 +8,8 @@ namespace Slang
     bool metaOp(IRInst* inst) {
         switch (inst->getOp())
         {
+        // These instructions only look at the parameter's type,
+        // so passing an undefined value to them is permissible
         case kIROp_IsBool:
         case kIROp_IsInt:
         case kIROp_IsUnsignedInt:
@@ -96,6 +98,23 @@ namespace Slang
 
         return false;
     }
+
+    bool constructor(IRFunc* func)
+    {
+        const UnownedStringSlice slice = toSlice("$init");
+
+        auto decoratorList = func->getDecorations();
+        for (auto head = decoratorList.first; head; head = head->next) {
+            if (auto name = as<IRNameHintDecoration>(head)) {
+                auto str = name->getName();
+                auto index = str.indexOf(slice);
+                if (index >= 0)
+                    return true;
+            }
+        }
+
+        return false;
+    }
 
     List<IRInst*> concernableUsers(IRInst* inst)
     {
@@ -141,24 +160,25 @@ namespace Slang
         {
         case kIROp_loop:
             // TODO: Ignore loops for now
-            // printf("LOOP: (%p)\n", as<IRLoop>(user));
-            // user->dump();
             return;
+
         // These instructions will store data...
         case kIROp_Store:
         case kIROp_SwizzledStore:
-        // TODO: for calls, should make check that the function is passing as an out param
+            // TODO: for calls, should make check that the function is passing as an out param
         case kIROp_Call:
         case kIROp_SPIRVAsm:
-        // For now assume that __intrinsic_asm blocks will do the right thing...
         case kIROp_GenericAsm:
+            // For now assume that __intrinsic_asm blocks will do the right thing...
             stores.add(user);
             break;
-        // For SPIRV asm instructions, need to check out the entire
-        // block when doing reachability checks
+
         case kIROp_SPIRVAsmOperandInst:
+            // For SPIRV asm instructions, need to check out the entire
+            // block when doing reachability checks
             stores.add(user->getParent());
             break;
+
         // ... and the rest will load/use them
         default:
             loads.add(user);
@@ -238,6 +258,10 @@ namespace Slang
         if (synthesized(func))
             return;
 
+        // Also skip for constructors; can add more complex diagnosis for such cases later
+        if (constructor(func))
+            return;
+
         auto firstBlock = func->getFirstBlock();
         if (!firstBlock)
             return;

tests/autodiff/material2/MxLayeredMaterial.slang

@@ -55,8 +55,7 @@ public struct MxLayeredMaterial : IMaterial
     public UsedMaterialInstance setupMaterialInstance(out MaterialInstanceData miData)
     {
         float3 albedo = getAlbedo(baseColor);
-        UsedMaterialInstance mi;
         for (uint i = 0; i < 3; i++) miData.data[i] = albedo[i];
-        return mi;
+        return UsedMaterialInstance();
     }
 }

tests/autodiff/treat-as-differentiable-1.slang

@@ -30,7 +30,7 @@ float use(IFoo o, float x)
 [numthreads(1, 1, 1)]
 void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
 {
-    B b;
+    B b = B();
     var p = diffPair(1.0);
     __bwd_diff(use)(b, p, 1.0);
     outputBuffer[0] = p.d;

tests/bugs/interface-type-self-ref.slang

@@ -27,6 +27,6 @@ int f(IFoo p)
 void computeMain(int3 dispatchThreadID: SV_DispatchThreadID)
 {
     int index = dispatchThreadID.x;
-    Impl impl;
+    Impl impl = Impl();
     outputBuffer[index] = f(impl);
 }

tests/bugs/specialize-existential-in-generic.slang

@@ -15,7 +15,7 @@ interface IFoo
 struct Impl : IFoo
 {
     struct Assoc : IAssoc { int getInner() { return 1; } }
-    Assoc getValue() { Assoc r; return r; }
+    Assoc getValue() { Assoc r = Assoc(); return r; }
 }
 
 struct GenType<T : IFoo>

tests/diagnostics/uninitialized-variables.slang

@@ -1,28 +1,31 @@
+//TEST:SIMPLE(filecheck=CHK): -target spirv
+
+// Using unitialized values
 int use_undefined_value(int k)
 {
     int x;
     x += k;
+    //CHK: error 41015: use of uninitialized value 'x'
     return x;
 }
 
+// Returning uninitialized values
 __generic<T>
 T generic_undefined_return()
 {
     T x;
+    //CHK: warning 41018: returning without initializing 'x'
     return x;
 }
 
+// No warnings here, even thought autodiff generates
+// IR which frequently returns undefined values
 struct DiffStruct : IDifferentiable
 {
     Texture2D tex;
 }
 
-[BackwardDifferentiable]
-float f(float x)
-{
-    return x;
-}
-
+// Structs and nested structs
 struct Data
 {
     float value;
@@ -33,29 +36,31 @@ struct NestedData
     Data data;
 };
 
-RWStructuredBuffer<Data> inputBuffer;
-RWStructuredBuffer<Data> outputBuffer;
+// Empty structures should not generate diagnostics
+// for empty default constructors
+struct EmptyStruct
+{
+    __init() {}
+};
 
-[numthreads(1, 1, 1)]
-void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
+float4 main()
 {
-    uint tid = dispatchThreadID.x;
+    Data inputData = Data(1.0);
 
-    Data inputData = inputBuffer[tid];
+    float undefVar;
     Data undefData;
     NestedData nestedData;
 
-    float uninitializedVariable;
+    float result = inputData.value;
 
-    // CHECK: warning
-    float outputData = inputData.value;
-    outputData += uninitializedVariable;
-    outputData += undefData.value;
-    outputData += nestedData.data.value;
+    //CHK: error 41015: use of uninitialized value 'undefVar'
+    result += undefVar;
+
+    //CHK: error 41015: use of uninitialized value 'undefData'
+    result += undefData.value;
 
-    var dp = diffPair(1.0);
-    __bwd_diff(f)(dp, 1.0);
-    outputData += dp.d.x;
+    //CHK: error 41015: use of uninitialized value 'nestedData'
+    result += nestedData.data.value;
 
-    outputBuffer[tid].value = outputData;
+    return float4(result);
 }

tests/experiments/generic/type-to-value-4.slang

@@ -67,7 +67,7 @@ void computeMain(uint3 dispatchThreadID : SV_DispatchThreadID)
 {
 
     // Err.. even though IGetE doesn't require an instanciation, not clear how to set it. So lets try with instanciation
-    B b;
+    B b = B();
     IGetE g = b;
 
     let e = g.getE();

tests/language-feature/if-let/if-let-1.slang

@@ -67,8 +67,8 @@ int test1<T>(T t)
 [numthreads(1, 1, 1)]
 void computeMain(uint3 dispatchThreadID: SV_DispatchThreadID)
 {
-    MyImpl1 impl1;
-    MyImpl2 impl2;
+    MyImpl1 impl1 = MyImpl1();
+    MyImpl2 impl2 = MyImpl2();
     // CHECK: 1
     // CHECK: 7
     outputBuffer[0] = test(impl1, 1);