bkramer created this revision.
bkramer added a reviewer: klimek.
bkramer added a subscriber: cfe-commits.
Herald added a subscriber: klimek.
One problem in clang-tidy and other clang tools face is that there is no
way to lookup an arbitrary name in the AST, that's buried deep inside Sema
and might not even be what the user wants as the new name may be freshly
inserted and not available in the AST.
A common use case for lookups is replacing one nested name with another
while minimizing namespace qualifications, so replacing 'ns::foo' with
'ns::bar' will use just 'bar' if we happen to be inside the namespace 'ns'.
This adds a little helper utility for exactly that use case.
http://reviews.llvm.org/D13931
Files:
include/clang/Tooling/Core/Lookup.h
lib/Tooling/Core/CMakeLists.txt
lib/Tooling/Core/Lookup.cpp
unittests/Tooling/CMakeLists.txt
unittests/Tooling/LookupTest.cpp
Index: unittests/Tooling/LookupTest.cpp
===================================================================
--- /dev/null
+++ unittests/Tooling/LookupTest.cpp
@@ -0,0 +1,92 @@
+//===- unittest/Tooling/LookupTest.cpp ------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestVisitor.h"
+#include "clang/Tooling/Core/Lookup.h"
+using namespace clang;
+
+namespace {
+struct GetDeclsVisitor : TestVisitor<GetDeclsVisitor> {
+ std::function<void(CallExpr *)> OnCall;
+
+ bool VisitCallExpr(CallExpr *Expr) {
+ if (OnCall)
+ OnCall(Expr);
+ return true;
+ }
+};
+
+static std::string replaceCallExpr(const CallExpr *Expr,
+ StringRef ReplacementString) {
+ const auto *Callee = cast<DeclRefExpr>(Expr->getCallee()->IgnoreImplicit());
+ const ValueDecl *FD = Callee->getDecl();
+ ASTContext &Context = FD->getASTContext();
+ const DeclContext *DC =
+ Context.getParents(ast_type_traits::DynTypedNode::create(*Expr))[0]
+ .get<DeclContext>();
+ return tooling::replaceNestedName(Callee->getQualifier(), DC, FD,
+ ReplacementString);
+}
+
+TEST(LookupTest, replaceNestedName) {
+ GetDeclsVisitor Visitor;
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("bar", replaceCallExpr(Expr, "bar"));
+ };
+ Visitor.runOver("namespace a { void foo(); }\n"
+ "namespace a { void f() { foo(); } }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver("namespace a { void foo(); }\n"
+ "namespace a { void f() { foo(); } }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("a::bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver("namespace a { void foo(); }\n"
+ "namespace b { void f() { a::foo(); } }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("a::bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver("namespace a { void foo(); }\n"
+ "namespace b { namespace a { void foo(); }\n"
+ "void f() { a::foo(); } }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("bar", replaceCallExpr(Expr, "bar"));
+ };
+ Visitor.runOver("void foo(); void f() { foo(); }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("::bar", replaceCallExpr(Expr, "bar"));
+ };
+ Visitor.runOver("void foo(); void f() { ::foo(); }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("a::bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver("namespace a { void foo(); }\nvoid f() { a::foo(); }\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("a::bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver("namespace a { int foo(); }\nauto f = a::foo()\n");
+
+ Visitor.OnCall = [](CallExpr *Expr) {
+ EXPECT_EQ("bar", replaceCallExpr(Expr, "a::bar"));
+ };
+ Visitor.runOver(
+ "namespace a { int foo(); }\nusing a::foo;\nauto f = foo()\n");
+}
+
+} // end anonymous namespace
Index: unittests/Tooling/CMakeLists.txt
===================================================================
--- unittests/Tooling/CMakeLists.txt
+++ unittests/Tooling/CMakeLists.txt
@@ -6,6 +6,7 @@
add_clang_unittest(ToolingTests
CommentHandlerTest.cpp
CompilationDatabaseTest.cpp
+ LookupTest.cpp
ToolingTest.cpp
RecursiveASTVisitorTest.cpp
RecursiveASTVisitorTestCallVisitor.cpp
Index: lib/Tooling/Core/Lookup.cpp
===================================================================
--- /dev/null
+++ lib/Tooling/Core/Lookup.cpp
@@ -0,0 +1,106 @@
+//===--- Lookup.cpp - Framework for clang refactoring tools ---------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines helper methods for clang tools performing name lookup.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Tooling/Core/Lookup.h"
+#include "clang/AST/Decl.h"
+using namespace clang;
+using namespace clang::tooling;
+
+static bool isInsideDifferentNamespaceWithSameName(const DeclContext *DeclA,
+ const DeclContext *DeclB) {
+ while (true) {
+ // Look past non-namespaces on DeclA.
+ while (DeclA && !isa<NamespaceDecl>(DeclA))
+ DeclA = DeclA->getParent();
+
+ // Look past non-namespaces on DeclB.
+ while (DeclB && !isa<NamespaceDecl>(DeclB))
+ DeclB = DeclB->getParent();
+
+ // We hit the root, no namespace collision.
+ if (!DeclA || !DeclB)
+ return false;
+
+ // Literally the same namespace, not a collision.
+ if (DeclA == DeclB)
+ return false;
+
+ // Now check the names. If they match we have a different namespace with the
+ // same name.
+ if (cast<NamespaceDecl>(DeclA)->getDeclName() ==
+ cast<NamespaceDecl>(DeclB)->getDeclName())
+ return true;
+
+ DeclA = DeclA->getParent();
+ DeclB = DeclB->getParent();
+ }
+}
+
+static std::string getBestNamespaceSubstr(const DeclContext *DeclA,
+ StringRef NewName,
+ bool HadLeadingColonColon) {
+ while (true) {
+ while (DeclA && !isa<NamespaceDecl>(DeclA))
+ DeclA = DeclA->getParent();
+
+ // Fully qualified it is! Leave :: in place if it's there already.
+ if (!DeclA)
+ return HadLeadingColonColon ? "::" + NewName.str() : NewName.str();
+
+ // Otherwise strip of redundant namespace qualifications from the new name.
+ std::string NS =
+ cast<NamespaceDecl>(DeclA)->getQualifiedNameAsString() + "::";
+ if (NewName.startswith("::"))
+ NS = "::" + NS;
+ if (NewName.startswith(NS))
+ return NewName.substr(NS.size());
+ DeclA = DeclA->getParent();
+ }
+}
+
+/// Check if the name specifier begins with a written "::".
+static bool isNameSpecifierGlobal(const NestedNameSpecifier *NNS) {
+ while (NNS) {
+ if (NNS->getKind() == NestedNameSpecifier::Global)
+ return true;
+ NNS = NNS->getPrefix();
+ }
+ return false;
+}
+
+std::string tooling::replaceNestedName(const NestedNameSpecifier *Use,
+ const DeclContext *UseContext,
+ const NamedDecl *FromDecl,
+ StringRef ReplacementString) {
+ // We can do a raw name replacement when we are not inside the namespace for
+ // the original function and it is not in the global namespace. The
+ // assumption is that outside the original namespace we must have a using
+ // statement that makes this work out and that other parts of this refactor
+ // will automatically fix using statements to point to the new function
+ const bool class_name_only = !Use;
+ const bool in_global_namespace =
+ isa<TranslationUnitDecl>(FromDecl->getDeclContext());
+ if (class_name_only && !in_global_namespace &&
+ !isInsideDifferentNamespaceWithSameName(FromDecl->getDeclContext(),
+ UseContext)) {
+ auto Pos = ReplacementString.rfind("::");
+ return Pos != StringRef::npos ? ReplacementString.substr(Pos + 2)
+ : ReplacementString;
+ }
+ // We did not match this because of a using statement, so we will need to
+ // figure out how good a namespace match we have with our destination type.
+ // We work backwards (from most specific possible namespace to least
+ // specific).
+ return getBestNamespaceSubstr(UseContext, ReplacementString,
+ isNameSpecifierGlobal(Use));
+}
Index: lib/Tooling/Core/CMakeLists.txt
===================================================================
--- lib/Tooling/Core/CMakeLists.txt
+++ lib/Tooling/Core/CMakeLists.txt
@@ -1,6 +1,7 @@
set(LLVM_LINK_COMPONENTS support)
add_clang_library(clangToolingCore
+ Lookup.cpp
Replacement.cpp
LINK_LIBS
Index: include/clang/Tooling/Core/Lookup.h
===================================================================
--- /dev/null
+++ include/clang/Tooling/Core/Lookup.h
@@ -0,0 +1,48 @@
+//===--- Lookup.h - Framework for clang refactoring tools --*- C++ -*------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines helper methods for clang tools performing name lookup.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLING_CORE_LOOKUP_H
+#define LLVM_CLANG_TOOLING_CORE_LOOKUP_H
+
+#include "clang/Basic/LLVM.h"
+#include <string>
+
+namespace clang {
+
+class DeclContext;
+class NamedDecl;
+class NestedNameSpecifier;
+
+namespace tooling {
+
+/// Emulate a lookup to replace one nested name specifier with another using as
+/// few additional namespace qualifications as possible.
+///
+/// This does not perform a full C++ lookup so ADL will not work.
+///
+/// \param Use The nested name to be replaced.
+/// \param UseContext The context in which the nested name is contained. This
+/// will be used to minimize namespace qualifications.
+/// \param FromDecl The declaration to which the nested name points.
+/// \param ReplacementString The replacement nested name. Should be fully
+/// qualified.
+/// \returns The new name to be inserted in place of the current nested name.
+std::string replaceNestedName(const NestedNameSpecifier *Use,
+ const DeclContext *UseContext,
+ const NamedDecl *FromDecl,
+ StringRef ReplacementString);
+
+} // end namespace tooling
+} // end namespace clang
+
+#endif // LLVM_CLANG_TOOLING_CORE_LOOKUP_H
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