[m-rev.] for review: fix bugs in parallel execution mechanism

[Peter Wang]

Estimated hours taken: 4
Branches: main

Fix two bugs in my recent changes to the parallel execution mechanism which
showed up on Sparc/Solaris.

runtime/mercury_context.c:
runtime/mercury_context.h:
	There was a problem with `MR_schedule_spark_locally' accessing the
	engine base address.  The register we thought contained the engine
	base address has different contents after a C function call (I guess
	due to register windows).  Since the function is short and should be
	inlined anyway, turn it into a macro.

runtime/mercury_thread.c:
	In `MR_init_thread', delay a call to `MR_save_registers' until after
	a context has been loaded into the engine, otherwise the program
	crashes on startup.

Index: runtime/mercury_context.c
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/runtime/mercury_context.c,v
retrieving revision 1.48
diff -u -r1.48 mercury_context.c
--- runtime/mercury_context.c	26 Sep 2006 03:53:20 -0000	1.48
+++ runtime/mercury_context.c	2 Oct 2006 02:33:02 -0000
@@ -415,21 +415,6 @@
     MR_UNLOCK(&MR_runqueue_lock, "schedule_spark_globally");
 }
 
-void
-MR_schedule_spark_locally(MR_Spark *spark)
-{
-    MR_Context  *ctxt;
-
-    ctxt = MR_ENGINE(MR_eng_this_context);
-
-    /* 
-    ** Only the engine running the context is allowed to access
-    ** the context's spark stack, so no locking is required here.
-    */
-    spark->MR_spark_next = ctxt->MR_ctxt_spark_stack;
-    ctxt->MR_ctxt_spark_stack = spark;
-}
-
 
 MR_define_extern_entry(MR_do_runnext);
 
Index: runtime/mercury_context.h
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/runtime/mercury_context.h,v
retrieving revision 1.31
diff -u -r1.31 mercury_context.h
--- runtime/mercury_context.h	26 Sep 2006 03:53:20 -0000	1.31
+++ runtime/mercury_context.h	2 Oct 2006 02:34:32 -0000
@@ -319,11 +319,6 @@
 ** Append the given spark onto the end of the spark queue.
 */
 extern  void        MR_schedule_spark_globally(MR_Spark *spark);
-
-/*
-** Push the given spark onto the hot end of the context's spark stack.
-*/
-extern  void        MR_schedule_spark_locally(MR_Spark *spark);
 #endif /* !MR_HIGHLEVEL_CODE */
 
 #ifndef MR_HIGHLEVEL_CODE
@@ -366,6 +361,19 @@
     (MR_num_idle_engines != 0 &&                                \
     MR_num_outstanding_contexts_and_sparks < MR_max_outstanding_contexts)
 
+  #define MR_schedule_spark_locally(spark)                              \
+    do {                                                                \
+        MR_Context  *ssl_ctxt;                                          \
+                                                                        \
+        /*                                                              \
+        ** Only the engine running the context is allowed to access     \
+        ** the context's spark stack, so no locking is required here.   \
+        */                                                              \
+        ssl_ctxt = MR_ENGINE(MR_eng_this_context);                      \
+        spark->MR_spark_next = ssl_ctxt->MR_ctxt_spark_stack;           \
+        ssl_ctxt->MR_ctxt_spark_stack = spark;                          \
+    } while (0)
+
 #endif /* !MR_HIGHLEVEL_CODE */
 
 #ifndef MR_CONSERVATIVE_GC
Index: runtime/mercury_thread.c
===================================================================
RCS file: /home/mercury/mercury1/repository/mercury/runtime/mercury_thread.c,v
retrieving revision 1.26
diff -u -r1.26 mercury_thread.c
--- runtime/mercury_thread.c	26 Sep 2006 03:53:22 -0000	1.26
+++ runtime/mercury_thread.c	30 Sep 2006 04:09:50 -0000
@@ -106,8 +106,6 @@
 #endif
     MR_load_engine_regs(MR_cur_engine());
 
-    MR_save_registers();
-
 #ifdef  MR_THREAD_SAFE
     MR_ENGINE(MR_eng_owner_thread) = pthread_self();
 #endif
@@ -129,6 +127,7 @@
                     MR_create_context("init_thread", NULL);
             }
             MR_load_context(MR_ENGINE(MR_eng_this_context));
+            MR_save_registers();
             return MR_TRUE;
         
         default:
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