[clang][AST] Fix AST IgnoreUnlessSpelledInSource traversal nullptr dereference by JonathanMarriott · Pull Request #146103 · llvm/llvm-project (original) (raw)
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Fixes #146101, in summary dumping a catch(...) statement using IgnoreUnlessSpelledInSource AST traversal causes a seg fault, as the variable declaration of the catch is nullptr.
Diagnosed the cause by attaching the debugger to clang-query, this PR adds a fix to check for nullptr before accessing the isImplicit() method of the Decl pointee in the AST node traverser visitor
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Clang issues not falling into any other category
Language frontend issues, e.g. anything involving "Sema"
labels
@llvm/pr-subscribers-clang
Author: Jonathan Marriott (JonathanMarriott)
Changes
Fixes #146101, in summary dumping a catch(...) statement using IgnoreUnlessSpelledInSource AST traversal causes a seg fault, as the variable declaration of the catch is nullptr.
Diagnosed the cause by attaching the debugger to clang-query, this PR adds a fix to check for nullptr before accessing the isImplicit() method of the Decl pointee in the AST node traverser visitor
Full diff: https://github.com/llvm/llvm-project/pull/146103.diff
2 Files Affected:
- (modified) clang/include/clang/AST/ASTNodeTraverser.h (+1-1)
- (modified) clang/unittests/AST/ASTTraverserTest.cpp (+75)
diff --git a/clang/include/clang/AST/ASTNodeTraverser.h b/clang/include/clang/AST/ASTNodeTraverser.h index 8d02a50e2e8a5..8ebabb2bde10d 100644 --- a/clang/include/clang/AST/ASTNodeTraverser.h +++ b/clang/include/clang/AST/ASTNodeTraverser.h @@ -99,7 +99,7 @@ class ASTNodeTraverser TraversalKind GetTraversalKind() const { return Traversal; }
void Visit(const Decl *D, bool VisitLocs = false) {
- if (Traversal == TK_IgnoreUnlessSpelledInSource && D->isImplicit())
if (Traversal == TK_IgnoreUnlessSpelledInSource && D && D->isImplicit()) return;
getNodeDelegate().AddChild([=] {
diff --git a/clang/unittests/AST/ASTTraverserTest.cpp b/clang/unittests/AST/ASTTraverserTest.cpp index 8b6e3e90c0ea6..988e81d8e51de 100644 --- a/clang/unittests/AST/ASTTraverserTest.cpp +++ b/clang/unittests/AST/ASTTraverserTest.cpp @@ -28,6 +28,10 @@ class NodeTreePrinter : public TextTreeStructure { : TextTreeStructure(OS, /* showColors */ false), OS(OS) {}
void Visit(const Decl *D) {
- if (!D) {
OS << "<<<NULL>>>";return;- } OS << D->getDeclKindName() << "Decl"; if (auto *ND = dyn_cast(D)) { OS << " '" << ND->getDeclName() << "'"; @@ -1932,4 +1936,75 @@ CXXRewrittenBinaryOperator } }
+TEST(Traverse, CatchStatements) { +
- auto AST = buildASTFromCode(R"cpp( +void test() +{
- try
- {
- int a;
- }
- catch (...)
- {
- int b;
- }
- try
- {
- int a;
- }
- catch (const int&)
- {
- int b;
- } +} +)cpp");
- auto BN =
ast_matchers::match(cxxCatchStmt().bind("catch"), AST->getASTContext());- EXPECT_EQ(BN.size(), 2u);
- const auto *catchWithoutDecl = BN[0].getNodeAs("catch");
- llvm::StringRef Expected = R"cpp( +CXXCatchStmt +|-<<>> +`-CompoundStmt
- `-DeclStmt
- `-VarDecl 'b'
+)cpp";
- EXPECT_EQ(dumpASTString(TK_AsIs, catchWithoutDecl), Expected);
- Expected = R"cpp( +CXXCatchStmt +|-<<>> +`-CompoundStmt
- `-DeclStmt
- `-VarDecl 'b'
+)cpp";
- EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource, catchWithoutDecl),
Expected);- const auto *catchWithDecl = BN[1].getNodeAs("catch");
- Expected = R"cpp( +CXXCatchStmt +|-VarDecl '' +`-CompoundStmt
- `-DeclStmt
- `-VarDecl 'b'
+)cpp";
- EXPECT_EQ(dumpASTString(TK_AsIs, catchWithDecl), Expected);
- Expected = R"cpp( +CXXCatchStmt +|-VarDecl '' +`-CompoundStmt
- `-DeclStmt
- `-VarDecl 'b'
+)cpp";
- EXPECT_EQ(dumpASTString(TK_IgnoreUnlessSpelledInSource, catchWithDecl),
Expected);
+} + } // namespace clang
Thank you for the patch! Please add a release note to "clang/docs/ReleaseNotes.rst" so users can know the improvement. Please add a tag to the beginning of the PR title in square brackets like other PRs. E.g. [clang].
Fix AST IgnoreUnlessSpelledInSource traversal nullptr dereference [clang] Fix AST IgnoreUnlessSpelledInSource traversal nullptr dereference
[clang] Fix AST IgnoreUnlessSpelledInSource traversal nullptr dereference [clang][AST] Fix AST IgnoreUnlessSpelledInSource traversal nullptr dereference
Thank you for the patch! Please add a release note to "clang/docs/ReleaseNotes.rst" so users can know the improvement. Please add a tag to the beginning of the PR title in square brackets like other PRs. E.g.
[clang].
Thanks, I've added a release note in what I think is the appropriate section!
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LGTM, thank you for the fix! Once precommit CI comes back green, I can land the changes on your behalf.
@JonathanMarriott Congratulations on having your first Pull Request (PR) merged into the LLVM Project!
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Language frontend issues, e.g. anything involving "Sema"
Clang issues not falling into any other category