Merge pull request swiftlang#34513 from varungandhi-apple/vg-ast-fix-clangtypeconverter-crash

[AST] Account for parameter bridging in Clang type computation.

Author: varungandhi-apple

include/swift/Option/FrontendOptions.td

@@ -665,7 +665,8 @@ def experimental_spi_imports :
 def experimental_print_full_convention :
  Flag<["-"], "experimental-print-full-convention">,
  HelpText<"When emitting a module interface or SIL, emit additional @convention"
-          " arguments, regardless of whether they were written in the source">;
+          " arguments, regardless of whether they were written in the source."
+          " Also requires -use-clang-function-types to be enabled.">;
 
 def experimental_one_way_closure_params :
   Flag<["-"], "experimental-one-way-closure-params">,

lib/AST/ClangTypeConverter.cpp

@@ -623,13 +623,44 @@ clang::QualType ClangTypeConverter::visitEnumType(EnumType *type) {
 }
 
 clang::QualType ClangTypeConverter::visitFunctionType(FunctionType *type) {
-  // We must've already computed it before if applicable.
-  return clang::QualType(type->getClangTypeInfo().getType(), 0);
+  const clang::Type *clangTy = nullptr;
+  auto repr = type->getRepresentation();
+  bool useClangTypes = type->getASTContext().LangOpts.UseClangFunctionTypes;
+  if (useClangTypes && (getSILFunctionLanguage(convertRepresentation(repr)) ==
+                        SILFunctionLanguage::C)) {
+    clangTy = type->getClangTypeInfo().getType();
+  } else if (!useClangTypes || repr == FunctionTypeRepresentation::Swift) {
+    // C function pointer types themselves are not bridged but their components
+    // can be. If a component is an @convention(block) function, it may be
+    // bridged to a Swift function type.
+    auto newRepr = (repr == FunctionTypeRepresentation::Swift
+                        ? FunctionTypeRepresentation::Block
+                        : repr);
+    clangTy = getFunctionType(type->getParams(), type->getResult(), newRepr);
+  }
+  return clang::QualType(clangTy, 0);
 }
 
 clang::QualType ClangTypeConverter::visitSILFunctionType(SILFunctionType *type) {
-  // We must've already computed it before if applicable.
-  return clang::QualType(type->getClangTypeInfo().getType(), 0);
+  const clang::Type *clangTy = nullptr;
+  auto repr = type->getRepresentation();
+  bool useClangTypes = type->getASTContext().LangOpts.UseClangFunctionTypes;
+  if (useClangTypes &&
+      (getSILFunctionLanguage(repr) == SILFunctionLanguage::C)) {
+    clangTy = type->getClangTypeInfo().getType();
+  } else if (!useClangTypes || repr == SILFunctionTypeRepresentation::Thick) {
+    // C function pointer types themselves are not bridged but their components
+    // can be. If a component is an @convention(block) function, it may be
+    // bridged to a Swift function type.
+    auto newRepr = (repr == SILFunctionTypeRepresentation::Thick
+                        ? SILFunctionTypeRepresentation::Block
+                        : repr);
+    auto results = type->getResults();
+    auto optionalResult =
+        results.empty() ? None : llvm::Optional<SILResultInfo>(results[0]);
+    clangTy = getFunctionType(type->getParameters(), optionalResult, newRepr);
+  }
+  return clang::QualType(clangTy, 0);
 }
 
 clang::QualType

test/ClangImporter/blocks_returning_bool.swift

@@ -1,5 +1,9 @@
 // RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen %s -I %S/Inputs/ | %FileCheck %s
 
+// Check that bridging an @convention(c)'s function's @convention(block)
+// parameter to a Swift function type doesn't crash the compiler.
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -emit-silgen %s -I %S/Inputs/ -o /dev/null -use-clang-function-types -experimental-print-full-convention
+
 // REQUIRES: objc_interop
 
 import Foundation

test/ClangImporter/clang-function-types.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend -typecheck -swift-version 5 -emit-module-interface-path - -sdk %clang-importer-sdk -enable-library-evolution %s -experimental-print-full-convention | %FileCheck %s
+// RUN: %target-swift-frontend -typecheck -swift-version 5 -emit-module-interface-path - -sdk %clang-importer-sdk -enable-library-evolution %s -experimental-print-full-convention -use-clang-function-types | %FileCheck %s
 
 import ctypes
 

test/ModuleInterface/full-convention.swift

@@ -1,4 +1,4 @@
-// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -swift-version 5 -emit-module-interface-path - -enable-library-evolution %s -experimental-print-full-convention | %FileCheck %s
+// RUN: %target-swift-frontend(mock-sdk: %clang-importer-sdk) -typecheck -swift-version 5 -emit-module-interface-path - -enable-library-evolution %s -experimental-print-full-convention -use-clang-function-types | %FileCheck %s
 
 import ctypes