[PATCH] D143428: [clang][deps] Fix race condition

[Jan Svoboda via Phabricator via cfe-commits]

jansvoboda11 created this revision.
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D140176 <https://reviews.llvm.org/D140176> introduced new `FullDeps` API that's 
not thread-safe, breaking the class invariant. This was causing race condition 
when `clang-scan-deps` was run with multiple threads.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D143428

Files:
  clang/tools/clang-scan-deps/ClangScanDeps.cpp


Index: clang/tools/clang-scan-deps/ClangScanDeps.cpp
===================================================================
--- clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -252,14 +252,17 @@
 public:
   void mergeDeps(StringRef Input, TranslationUnitDeps TUDeps,
                  size_t InputIndex) {
+    mergeDeps(std::move(TUDeps.ModuleGraph), InputIndex);
+
     InputDeps ID;
     ID.FileName = std::string(Input);
     ID.ContextHash = std::move(TUDeps.ID.ContextHash);
     ID.FileDeps = std::move(TUDeps.FileDeps);
     ID.ModuleDeps = std::move(TUDeps.ClangModuleDeps);
-    mergeDeps(std::move(TUDeps.ModuleGraph), InputIndex);
     ID.DriverCommandLine = std::move(TUDeps.DriverCommandLine);
     ID.Commands = std::move(TUDeps.Commands);
+
+    std::unique_lock<std::mutex> ul(Lock);
     Inputs.push_back(std::move(ID));
   }
 



Index: clang/tools/clang-scan-deps/ClangScanDeps.cpp
===================================================================
--- clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -252,14 +252,17 @@
 public:
   void mergeDeps(StringRef Input, TranslationUnitDeps TUDeps,
                  size_t InputIndex) {
+    mergeDeps(std::move(TUDeps.ModuleGraph), InputIndex);
+
     InputDeps ID;
     ID.FileName = std::string(Input);
     ID.ContextHash = std::move(TUDeps.ID.ContextHash);
     ID.FileDeps = std::move(TUDeps.FileDeps);
     ID.ModuleDeps = std::move(TUDeps.ClangModuleDeps);
-    mergeDeps(std::move(TUDeps.ModuleGraph), InputIndex);
     ID.DriverCommandLine = std::move(TUDeps.DriverCommandLine);
     ID.Commands = std::move(TUDeps.Commands);
+
+    std::unique_lock<std::mutex> ul(Lock);
     Inputs.push_back(std::move(ID));
   }
 

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