[PATCH] D131675: [clang] SIGSEGV fix at clang::ASTContext::getRawCommentForDeclNoCacheImpl

[Ivan Murashko via Phabricator via llvm-commits]

ivanmurashko created this revision.
ivanmurashko added reviewers: sammccall, aaron.ballman.
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The `File` might point to an invalid `FileID` at the case of broken AST. That leads to clang/clangd crash while processing comments. Relevant part of the crash is below

   #4 0x00007f1d7fbf95bc std::_Rb_tree<unsigned int, std::pair<unsigned int const, clang::RawComment*>, std::_Select1st<std::pair<unsigned int const, clang::RawComment*>>, std::less<unsigned int>, std::allocator<std::pair<unsigned int const
  , clang::RawComment*>>>::_M_lower_bound(std::_Rb_tree_node<std::pair<unsigned int const, clang::RawComment*>> const*, std::_Rb_tree_node_base const*, unsigned int const&) const /usr/include/c++/8/bits/stl_tree.h:1911:2
   #5 0x00007f1d7fbf95bc std::_Rb_tree<unsigned int, std::pair<unsigned int const, clang::RawComment*>, std::_Select1st<std::pair<unsigned int const, clang::RawComment*>>, std::less<unsigned int>, std::allocator<std::pair<unsigned int const
  , clang::RawComment*>>>::lower_bound(unsigned int const&) const /usr/include/c++/8/bits/stl_tree.h:1214:56
   #6 0x00007f1d7fbf95bc std::map<unsigned int, clang::RawComment*, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, clang::RawComment*>>>::lower_bound(unsigned int const&) const /usr/include/c++/8/bits/stl_map.h:1264:3
  6
   #7 0x00007f1d7fbf95bc clang::ASTContext::getRawCommentForDeclNoCacheImpl(clang::Decl const*, clang::SourceLocation, std::map<unsigned int, clang::RawComment*, std::less<unsigned int>, std::allocator<std::pair<unsigned int const, clang::R
  awComment*>>> const&) const /home/ivanmurashko/local/llvm-project/clang/lib/AST/ASTContext.cpp:226:57

The corresponding lit test that reproduces that crash was also added


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D131675

Files:
  clang/lib/AST/ASTContext.cpp
  clang/test/AST/ast-crash-doc.cpp


Index: clang/test/AST/ast-crash-doc.cpp
===================================================================
--- /dev/null
+++ clang/test/AST/ast-crash-doc.cpp
@@ -0,0 +1,30 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+// RUN: %clang_cc1 -emit-module -x c++ -fmodules -I %t/Inputs -fmodule-name=aa %t/Inputs/module.modulemap -o %t/aa.pcm
+// RUN: rm %t/Inputs/b.h
+// RUN: not %clang_cc1 -x c++ -Wdocumentation -ast-dump-all -fmodules -I %t/Inputs -fmodule-file=%t/aa.pcm %t/test.cpp | FileCheck %s
+
+//--- Inputs/module.modulemap
+module aa {
+    header "a.h"
+    header "b.h"
+}
+
+//--- Inputs/a.h
+// empty file
+
+//--- Inputs/b.h
+/// test foo @return
+int foo();
+
+
+//--- test.cpp
+#include "a.h"
+
+/// test comment at the primary file
+
+int a = foo();
+
+
+// CHECK: TranslationUnitDecl
Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -298,6 +298,9 @@
     return nullptr;
 
   const FileID File = SourceMgr.getDecomposedLoc(DeclLoc).first;
+  if (!File.isValid()) {
+    return nullptr;
+  }
   const auto CommentsInThisFile = Comments.getCommentsInFile(File);
   if (!CommentsInThisFile || CommentsInThisFile->empty())
     return nullptr;


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