[wasm][SIL/IRGen] HACK: Always forward extra argument to match callee and caller signature

This is a legacy solution for the KeyPath calling convention problem
described in https://forums.swift.org/t/wasm-support/16087/21. This
patch will be replaced by swiftlang#66273

Author: kateinoigakukun

lib/IRGen/GenKeyPath.cpp

@@ -224,7 +224,8 @@ getAccessorForComputedComponent(IRGenModule &IGM,
       componentArgsBuf = params.claimNext();
       // Pass the argument pointer down to the underlying function, if it
       // wants it.
-      if (hasSubscriptIndices) {
+      // Always forward extra argument to match callee and caller signature on WebAssembly
+      if (hasSubscriptIndices || IGM.TargetInfo.OutputObjectFormat == llvm::Triple::Wasm) {
         forwardedArgs.add(componentArgsBuf);
       }
       break;
@@ -250,6 +251,10 @@ getAccessorForComputedComponent(IRGenModule &IGM,
                                forwardingSubs,
                                &ignoreWitnessMetadata,
                                forwardedArgs);
+    } else if (IGM.Triple.isOSBinFormatWasm()) {
+      // wasm: Add null swift.type pointer to match signature even when there is
+      // no generic environment.
+      forwardedArgs.add(llvm::ConstantPointerNull::get(IGM.TypeMetadataPtrTy));
     }
     auto fnPtr =
         FunctionPointer::forDirect(IGM, accessorFn, /*secondaryValue*/ nullptr,

lib/SIL/Verifier/SILVerifier.cpp

@@ -304,8 +304,9 @@ void verifyKeyPathComponent(SILModule &M,
                 SILFunctionTypeRepresentation::Thin,
               "getter should be a thin function");
 
-      require(substGetterType->getNumParameters() == 1 + hasIndices,
-              "getter should have one parameter");
+      // FIXME(katei): Disabled for now. Will be replaced by keypath cc
+      // require(substGetterType->getNumParameters() == 1 + hasIndices,
+      //         "getter should have one parameter");
       auto baseParam = substGetterType->getParameters()[0];
       require(baseParam.getConvention() == normalArgConvention,
               "getter base parameter should have normal arg convention");
@@ -356,8 +357,9 @@ void verifyKeyPathComponent(SILModule &M,
                 SILFunctionTypeRepresentation::Thin,
               "setter should be a thin function");
 
-      require(substSetterType->getNumParameters() == 2 + hasIndices,
-              "setter should have two parameters");
+      // FIXME(katei): Disabled for now. Will be replaced by keypath cc
+      // require(substSetterType->getNumParameters() == 2 + hasIndices,
+      //         "setter should have two parameters");
 
       auto newValueParam = substSetterType->getParameters()[0];
       // TODO: This should probably be unconditionally +1 when we

lib/SILGen/SILGenExpr.cpp

@@ -2987,6 +2987,7 @@ static SILFunction *getOrCreateKeyPathGetter(SILGenModule &SGM,
     }
   }
 
+  auto Target = SGM.getASTContext().LangOpts.Target;
   auto genericSig =
       genericEnv ? genericEnv->getGenericSignature().getCanonicalSignature()
                  : nullptr;
@@ -2995,6 +2996,14 @@ static SILFunction *getOrCreateKeyPathGetter(SILGenModule &SGM,
     genericEnv = nullptr;
   }
 
+  // Add empty generic type parameter to match function signature on WebAssembly
+  if (!genericSig && Target.isOSBinFormatWasm()) {
+    auto param = GenericTypeParamType::get(false, 0, 0, SGM.getASTContext());
+    auto sig = GenericSignature::get(param, { });
+    genericSig = CanGenericSignature(sig);
+    genericEnv = sig.getGenericEnvironment();
+  }
+
   // Build the signature of the thunk as expected by the keypath runtime.
   auto signature = [&]() {
     CanType loweredBaseTy, loweredPropTy;
@@ -3010,7 +3019,8 @@ static SILFunction *getOrCreateKeyPathGetter(SILGenModule &SGM,
     SmallVector<SILParameterInfo, 2> params;
     params.push_back({loweredBaseTy, paramConvention});
     auto &C = SGM.getASTContext();
-    if (!indexes.empty())
+    // Always take indexes parameter to match callee and caller signature on WebAssembly
+    if (!indexes.empty() || C.LangOpts.Target.isOSBinFormatWasm())
       params.push_back({C.getUnsafeRawPointerType()->getCanonicalType(),
                         ParameterConvention::Direct_Unowned});
 
@@ -3070,7 +3080,8 @@ static SILFunction *getOrCreateKeyPathGetter(SILGenModule &SGM,
   }
   auto baseArg = entry->createFunctionArgument(baseArgTy);
   SILValue indexPtrArg;
-  if (!indexes.empty()) {
+  // Always take indexes parameter to match callee and caller signature on WebAssembly
+  if (!indexes.empty() || Target.isOSBinFormatWasm()) {
     auto indexArgTy =
         subSGF.silConv.getSILType(signature->getParameters()[1], signature,
                                   subSGF.F.getTypeExpansionContext());
@@ -3160,6 +3171,7 @@ static SILFunction *getOrCreateKeyPathSetter(SILGenModule &SGM,
     }
   }
 
+  auto Target = SGM.getASTContext().LangOpts.Target;
   auto genericSig =
       genericEnv ? genericEnv->getGenericSignature().getCanonicalSignature()
                  : nullptr;
@@ -3168,6 +3180,14 @@ static SILFunction *getOrCreateKeyPathSetter(SILGenModule &SGM,
     genericEnv = nullptr;
   }
 
+  // Add empty generic type parameter to match function signature on WebAssembly
+  if (!genericSig && Target.isOSBinFormatWasm()) {
+    auto param = GenericTypeParamType::get(false, 0, 0, SGM.getASTContext());
+    auto sig = GenericSignature::get(param, { });
+    genericSig = CanGenericSignature(sig);
+    genericEnv = sig.getGenericEnvironment();
+  }
+
   // Build the signature of the thunk as expected by the keypath runtime.
   auto signature = [&]() {
     CanType loweredBaseTy, loweredPropTy;
@@ -3193,7 +3213,8 @@ static SILFunction *getOrCreateKeyPathSetter(SILGenModule &SGM,
                         ? ParameterConvention::Indirect_Inout
                         : paramConvention});
     // indexes
-    if (!indexes.empty())
+    // Always take indexes parameter to match callee and caller signature on WebAssembly
+    if (!indexes.empty() || C.LangOpts.Target.isOSBinFormatWasm())
       params.push_back({C.getUnsafeRawPointerType()->getCanonicalType(),
                         ParameterConvention::Direct_Unowned});
 
@@ -3249,7 +3270,8 @@ static SILFunction *getOrCreateKeyPathSetter(SILGenModule &SGM,
   auto baseArg = entry->createFunctionArgument(baseArgTy);
   SILValue indexPtrArg;
 
-  if (!indexes.empty()) {
+  // Always take indexes parameter to match callee and caller signature on WebAssembly
+  if (!indexes.empty() || Target.isOSBinFormatWasm()) {
     auto indexArgTy =
         subSGF.silConv.getSILType(signature->getParameters()[2], signature,
                                   subSGF.getTypeExpansionContext());
@@ -3342,6 +3364,7 @@ getOrCreateKeyPathEqualsAndHash(SILGenModule &SGM,
     return;
   }
 
+  auto Target = SGM.getASTContext().LangOpts.Target;
   auto genericSig =
       genericEnv ? genericEnv->getGenericSignature().getCanonicalSignature()
                  : nullptr;
@@ -3351,6 +3374,14 @@ getOrCreateKeyPathEqualsAndHash(SILGenModule &SGM,
     genericEnv = nullptr;
   }
 
+  // Add empty generic type parameter to match function signature on WebAssembly
+  if (!genericSig && Target.isOSBinFormatWasm()) {
+    auto param = GenericTypeParamType::get(false, 0, 0, SGM.getASTContext());
+    auto sig = GenericSignature::get(param, { });
+    genericSig = CanGenericSignature(sig);
+    genericEnv = sig.getGenericEnvironment();
+  }
+
   auto &C = SGM.getASTContext();
   auto unsafeRawPointerTy = C.getUnsafeRawPointerType()->getCanonicalType();
   auto boolTy = C.getBoolType()->getCanonicalType();

lib/SILOptimizer/SILCombiner/SILCombinerApplyVisitors.cpp

@@ -505,6 +505,13 @@ bool SILCombiner::tryOptimizeKeypathKVCString(ApplyInst *AI,
 }
 
 bool SILCombiner::tryOptimizeKeypath(ApplyInst *AI) {
+  // FIXME(katei): Disable for WebAssembly for now because
+  // KeyPath cc is unstable and KeyPathProjector hask violates
+  // some assert assumptions
+  SILModule &M = AI->getModule();
+  if (M.getASTContext().LangOpts.Target.isOSBinFormatWasm())
+    return false;
+
   if (SILFunction *callee = AI->getReferencedFunctionOrNull()) {
     return tryOptimizeKeypathApplication(AI, callee);
   }
@@ -550,6 +557,13 @@ bool SILCombiner::tryOptimizeKeypath(ApplyInst *AI) {
 ///   %addr = struct_element_addr/ref_element_addr %root_object
 ///   // use %inout_addr
 bool SILCombiner::tryOptimizeInoutKeypath(BeginApplyInst *AI) {
+  // FIXME(katei): Disable for WebAssembly for now because
+  // KeyPath cc is unstable and KeyPathProjector hask violates
+  // some assert assumptions
+  SILModule &M = AI->getModule();
+  if (M.getASTContext().LangOpts.Target.isOSBinFormatWasm())
+    return false;
+
   // Disable in OSSA because KeyPathProjector is not fully ported
   if (AI->getFunction()->hasOwnership())
     return false;

lib/SILOptimizer/Utils/KeyPathProjector.cpp

@@ -233,7 +233,22 @@ class GettablePropertyProjector : public ComponentProjector {
       assert(getter->getConventions().getNumSILArguments());
 
       auto ref = builder.createFunctionRef(loc, getter);
-      builder.createApply(loc, ref, subs, {addr, parentValue});
+
+      std::vector<SILValue> args{addr, parentValue};
+      // FIXME(wasm): For wasm, KeyPath getter always take indices parameter
+      // to match callee and caller signature. So need to pass stub pointer.
+      // See also: getOrCreateKeyPathSetter and getOrCreateKeyPathGetter
+      if (builder.getASTContext().LangOpts.Target.isOSBinFormatWasm()) {
+        auto IntTy = SILType::getBuiltinIntegerType(32, builder.getASTContext());
+        auto UnsafeRawPointerTy = SILType::getRawPointerType(builder.getASTContext());
+        auto zeroVal = SILValue(builder.createIntegerLiteral(loc, IntTy, 0));
+        auto stackBuffer = SILValue(builder.createAllocStack(loc, IntTy));
+        builder.createStore(loc, zeroVal, stackBuffer, StoreOwnershipQualifier::Unqualified);
+        auto nonePointer = builder.createUncheckedAddrCast(loc, stackBuffer, UnsafeRawPointerTy);
+        args.push_back(SILValue(nonePointer));
+      }
+
+      builder.createApply(loc, ref, subs, args);
 
       // If we were previously accessing a class member, we're done now.
       insertEndAccess(beginAccess, builder);