[commit: ghc] master: rts: Disable -hb with multiple capabilities (6555c6b)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/6555c6bb8447ed65d5da4bab462ee9da7dc3f97a/ghc

>---------------------------------------------------------------

commit 6555c6bb8447ed65d5da4bab462ee9da7dc3f97a
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Mon Sep 12 08:44:24 2016 -0400

    rts: Disable -hb with multiple capabilities
    
    Biographical profiling is not thread-safe as documented in #12019. Throw
    an error when it is used in this way.
    
    Test Plan: Validate
    
    Reviewers: simonmar, austin, erikd
    
    Reviewed By: erikd
    
    Subscribers: thomie
    
    Differential Revision: https://phabricator.haskell.org/D2516
    
    GHC Trac Issues: #12019


>---------------------------------------------------------------

6555c6bb8447ed65d5da4bab462ee9da7dc3f97a
 rts/ProfHeap.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/rts/ProfHeap.c b/rts/ProfHeap.c
index 956a250..c94b3e9 100644
--- a/rts/ProfHeap.c
+++ b/rts/ProfHeap.c
@@ -400,6 +400,13 @@ initHeapProfiling(void)
         errorBelch("cannot mix -hb and -hr");
         stg_exit(EXIT_FAILURE);
     }
+#ifdef THREADED_RTS
+    // See Trac #12019.
+    if (doingLDVProfiling() && RtsFlags.ParFlags.nCapabilities > 1) {
+        errorBelch("-hb cannot be used with multiple capabilities");
+        stg_exit(EXIT_FAILURE);
+    }
+#endif
 #endif
 
     // we only count eras if we're doing LDV profiling.  Otherwise era