[Lldb-commits] [PATCH] D69403: [Driver] Force llvm to install its handlers before lldb's

[Vedant Kumar via Phabricator via lldb-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG0877dd14e4e8: [Driver] Force llvm to install its handlers before lldb's (authored by vsk).
Herald added a project: LLDB.

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D69403/new/

https://reviews.llvm.org/D69403

Files:
  lldb/tools/driver/Driver.cpp


Index: lldb/tools/driver/Driver.cpp
===================================================================
--- lldb/tools/driver/Driver.cpp
+++ lldb/tools/driver/Driver.cpp
@@ -845,6 +845,25 @@
   }
   SBHostOS::ThreadCreated("<lldb.driver.main-thread>");
 
+  // Install llvm's signal handlers up front to prevent lldb's handlers from
+  // being ignored. This is (hopefully) a stopgap workaround.
+  //
+  // When lldb invokes an llvm API that installs signal handlers (e.g.
+  // llvm::sys::RemoveFileOnSignal, possibly via a compiler embedded within
+  // lldb), lldb's signal handlers are overriden if llvm is installing its
+  // handlers for the first time.
+  //
+  // To work around llvm's behavior, force it to install its handlers up front,
+  // and *then* install lldb's handlers. In practice this is used to prevent
+  // lldb test processes from exiting due to IO_ERR when SIGPIPE is received.
+  //
+  // Note that when llvm installs its handlers, it 1) records the old handlers
+  // it replaces and 2) re-installs the old handlers when its new handler is
+  // invoked. That means that a signal not explicitly handled by lldb can fall
+  // back to being handled by llvm's handler the first time it is received,
+  // and then by the default handler the second time it is received.
+  llvm::sys::AddSignalHandler([](void *) -> void {}, nullptr);
+
   signal(SIGINT, sigint_handler);
 #if !defined(_MSC_VER)
   signal(SIGPIPE, SIG_IGN);


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