[lld] de2dfc8 - [LLD] Avoid exiting with a locked mutex NFC

[Andrew Ng via llvm-commits]

Author: Andrew Ng
Date: 2020-01-28T16:44:44Z
New Revision: de2dfc8b203f0ff903e401acf7cc55552e63a2fd

URL: https://github.com/llvm/llvm-project/commit/de2dfc8b203f0ff903e401acf7cc55552e63a2fd
DIFF: https://github.com/llvm/llvm-project/commit/de2dfc8b203f0ff903e401acf7cc55552e63a2fd.diff

LOG: [LLD] Avoid exiting with a locked mutex NFC

In ErrorHandler::error(), rearrange code to avoid calling exitLld with
the mutex locked. Acquire mutex lock when flushing the output streams in
exitLld.

Differential Revision: https://reviews.llvm.org/D73281

Added: 
    

Modified: 
    lld/Common/ErrorHandler.cpp

Removed: 
    


################################################################################
diff  --git a/lld/Common/ErrorHandler.cpp b/lld/Common/ErrorHandler.cpp
index b6066b557cbf..fb848325f96c 100644
--- a/lld/Common/ErrorHandler.cpp
+++ b/lld/Common/ErrorHandler.cpp
@@ -62,8 +62,11 @@ void lld::exitLld(int val) {
   // avoid intermittent crashes on Windows when exiting.
   llvm_shutdown();
 
-  lld::outs().flush();
-  lld::errs().flush();
+  {
+    std::lock_guard<std::mutex> lock(mu);
+    lld::outs().flush();
+    lld::errs().flush();
+  }
   _exit(val);
 }
 
@@ -191,20 +194,26 @@ void ErrorHandler::error(const Twine &msg) {
     }
   }
 
-  std::lock_guard<std::mutex> lock(mu);
+  bool exit = false;
+  {
+    std::lock_guard<std::mutex> lock(mu);
+
+    if (errorLimit == 0 || errorCount < errorLimit) {
+      lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
+                  << "error: " << Colors::RESET << msg << "\n";
+    } else if (errorCount == errorLimit) {
+      lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
+                  << "error: " << Colors::RESET << errorLimitExceededMsg
+                  << "\n";
+      exit = exitEarly;
+    }
 
-  if (errorLimit == 0 || errorCount < errorLimit) {
-    lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
-                << "error: " << Colors::RESET << msg << "\n";
-  } else if (errorCount == errorLimit) {
-    lld::errs() << sep << getLocation(msg) << ": " << Colors::RED
-                << "error: " << Colors::RESET << errorLimitExceededMsg << "\n";
-    if (exitEarly)
-      exitLld(1);
+    sep = getSeparator(msg);
+    ++errorCount;
   }
 
-  sep = getSeparator(msg);
-  ++errorCount;
+  if (exit)
+    exitLld(1);
 }
 
 void ErrorHandler::fatal(const Twine &msg) {