Swift: extract mangler into a separate class

swift/extractor/BUILD.bazel

@@ -12,6 +12,7 @@ swift_cc_binary(
         "//swift/extractor/config",
         "//swift/extractor/infra",
         "//swift/extractor/invocation",
+        "//swift/extractor/mangler",
         "//swift/extractor/remapping",
         "//swift/extractor/translators",
         "//swift/third_party/swift-llvm-support",

swift/extractor/mangler/BUILD.bazel

@@ -0,0 +1,12 @@
+load("//swift:rules.bzl", "swift_cc_library")
+
+swift_cc_library(
+    name = "mangler",
+    srcs = glob(["*.cpp"]),
+    hdrs = glob(["*.h"]),
+    visibility = ["//swift:__subpackages__"],
+    deps = [
+        "//swift/extractor/trap",
+        "//swift/third_party/swift-llvm-support",
+    ],
+)

swift/extractor/mangler/SwiftMangler.cpp

@@ -0,0 +1,32 @@
+#include "swift/extractor/mangler/SwiftMangler.h"
+#include "swift/extractor/trap/generated/decl/TrapClasses.h"
+#include <swift/AST/Module.h>
+#include <sstream>
+
+using namespace codeql;
+
+std::string SwiftMangler::mangledName(const swift::Decl& decl) {
+  assert(llvm::isa<swift::ValueDecl>(decl));
+  auto& valueDecl = llvm::cast<swift::ValueDecl>(decl);
+  std::string_view moduleName = decl.getModuleContext()->getRealName().str();
+  // ASTMangler::mangleAnyDecl crashes when called on `ModuleDecl`
+  if (decl.getKind() == swift::DeclKind::Module) {
+    return std::string{moduleName};
+  }
+  std::ostringstream ret;
+  // stamp all declarations with an id-ref of the containing module
+  ret << '{' << ModuleDeclTag::prefix << '_' << moduleName << '}';
+  if (decl.getKind() == swift::DeclKind::TypeAlias) {
+    // In cases like this (when coming from PCM)
+    //  typealias CFXMLTree = CFTree
+    //  typealias CFXMLTreeRef = CFXMLTree
+    // mangleAnyDecl mangles both CFXMLTree and CFXMLTreeRef into 'So12CFXMLTreeRefa'
+    // which is not correct and causes inconsistencies. mangleEntity makes these two distinct
+    // prefix adds a couple of special symbols, we don't necessary need them
+    ret << mangler.mangleEntity(&valueDecl);
+  } else {
+    // prefix adds a couple of special symbols, we don't necessary need them
+    ret << mangler.mangleAnyDecl(&valueDecl, /* prefix = */ false);
+  }
+  return ret.str();
+}

swift/extractor/mangler/SwiftMangler.h

@@ -0,0 +1,18 @@
+#pragma once
+
+#include <vector>
+#include <unordered_set>
+#include <filesystem>
+
+#include <swift/AST/ASTMangler.h>
+
+namespace codeql {
+class SwiftMangler {
+ public:
+  std::string mangledName(const swift::Decl& decl);
+
+ private:
+  swift::Mangle::ASTMangler mangler;
+};
+
+}  // namespace codeql

swift/extractor/translators/BUILD.bazel

@@ -7,6 +7,7 @@ swift_cc_library(
     visibility = ["//swift:__subpackages__"],
     deps = [
         "//swift/extractor/infra",
+        "//swift/extractor/mangler",
         "//swift/third_party/swift-llvm-support",
     ],
 )

swift/extractor/translators/DeclTranslator.cpp

@@ -3,7 +3,7 @@
 #include <swift/AST/GenericParamList.h>
 #include <swift/AST/ParameterList.h>
 #include "swift/extractor/infra/SwiftDiagnosticKind.h"
-#include "swift/AST/PropertyWrappers.h"
+#include <swift/AST/PropertyWrappers.h>
 
 namespace codeql {
 namespace {
@@ -303,27 +303,7 @@ std::optional<codeql::ModuleDecl> DeclTranslator::translateModuleDecl(
 }
 
 std::string DeclTranslator::mangledName(const swift::ValueDecl& decl) {
-  std::string_view moduleName = decl.getModuleContext()->getRealName().str();
-  // ASTMangler::mangleAnyDecl crashes when called on `ModuleDecl`
-  if (decl.getKind() == swift::DeclKind::Module) {
-    return std::string{moduleName};
-  }
-  std::ostringstream ret;
-  // stamp all declarations with an id-ref of the containing module
-  ret << '{' << ModuleDeclTag::prefix << '_' << moduleName << '}';
-  if (decl.getKind() == swift::DeclKind::TypeAlias) {
-    // In cases like this (when coming from PCM)
-    //  typealias CFXMLTree = CFTree
-    //  typealias CFXMLTreeRef = CFXMLTree
-    // mangleAnyDecl mangles both CFXMLTree and CFXMLTreeRef into 'So12CFXMLTreeRefa'
-    // which is not correct and causes inconsistencies. mangleEntity makes these two distinct
-    // prefix adds a couple of special symbols, we don't necessary need them
-    ret << mangler.mangleEntity(&decl);
-  } else {
-    // prefix adds a couple of special symbols, we don't necessary need them
-    ret << mangler.mangleAnyDecl(&decl, /* prefix = */ false);
-  }
-  return ret.str();
+  return mangler.mangledName(decl);
 }
 
 void DeclTranslator::fillAbstractFunctionDecl(const swift::AbstractFunctionDecl& decl,

swift/extractor/translators/DeclTranslator.h

@@ -5,6 +5,7 @@
 
 #include "swift/extractor/translators/TranslatorBase.h"
 #include "swift/extractor/trap/generated/decl/TrapClasses.h"
+#include "swift/extractor/mangler/SwiftMangler.h"
 
 namespace codeql {
 
@@ -86,7 +87,7 @@ class DeclTranslator : public AstTranslatorBase<DeclTranslator> {
     entry.module = dispatcher.fetchLabel(decl.getModuleContext());
   }
 
-  swift::Mangle::ASTMangler mangler;
+  SwiftMangler mangler;
 };
 
 }  // namespace codeql