add spath_assert

src/spath_mpi.c

@@ -2,6 +2,7 @@
 
 #include "spath.h"
 #include "spath_util.h"
+#include "spath_mpi.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -19,25 +20,109 @@ Functions to send/recv paths with MPI
 =========================================
 */
 
+spath_assert_mode_t spath_assert_mode = SPATH_ASSERT_ABORT; /* determines how spath_assert behaves on errors */
+
+/* Check that given condition is true.
+ * Returns 0 if assert passes, and 1 if assert fails.
+ * if in production mode:
+ *   - if condition is false, print msg and call MPI_Abort
+ * if in testing mode:
+ *   - execute allreduce on comm to verify condition is true on *all* procs,
+ *     if false on *any* proc, print msg and return error on all procs
+ * if in debugging mode:
+ *   - if condition is false, print msg and call while(1) to hang,
+ *     which allows someone to attach debugger */
+static int spath_assert(int condition, MPI_Comm comm, const char* format, ...)
+{
+  /* If in production mode and condition is false,
+   * then print error message and call abort. */
+  if (spath_assert_mode == SPATH_ASSERT_ABORT) {
+    if (! condition) {
+      /* print error message */
+      va_list ap;
+      va_start(ap, format);
+      vfprintf(stderr, format, ap);
+      va_end(ap);
+      fflush(stderr);
+
+      /* abort */
+      MPI_Abort(comm, -1);
+    }
+  }
+
+  /* If in debugging mode and condition is false,
+   * then print error message and hang so one can attach a debugger. */
+  if (spath_assert_mode == SPATH_ASSERT_HANG) {
+    if (! condition) {
+      /* print error message */
+      va_list ap;
+      va_start(ap, format);
+      vfprintf(stderr, format, ap);
+      va_end(ap);
+
+      /* hang, so user can attach a debugger */
+      fprintf(stderr, "Hanging in while(1) ...\n");
+      fflush(stderr);
+      while(1);
+    }
+  }
+
+  /* If in testing mode, check that condition is true on all procs in comm.
+   * If true everywhere, return SUCCESS.  Otherwise, print error message
+   * from one rank and return an error on all ranks. */
+  if (spath_assert_mode == SPATH_ASSERT_RETURN) {
+    /* verify that condition is true on all procs in comm */
+    int alltrue;
+    MPI_Allreduce(&condition, &alltrue, 1, MPI_INT, MPI_LAND, comm);
+    if (! alltrue) {
+      /* condition is false on at least one rank in comm,
+       * print the error message, but just from rank 0 */
+      int rank;
+      MPI_Comm_rank(comm, &rank);
+      if (rank == 0) {
+        va_list ap;
+        va_start(ap, format);
+        vfprintf(stderr, format, ap);
+        va_end(ap);
+        fflush(stderr);
+      }
+
+      /* everyone return an error from all ranks */
+      return 1;
+    }
+  }
+
+  /* condition is true */
+  return 0;
+}
+
 /* broacast path from root to all ranks in comm,
  * receivers must pass in a newly allocated path from spath_new() */
 int spath_bcast(spath* path, int root, MPI_Comm comm)
 {
   /* if pointer is NULL, throw an error */
-  if (path == NULL) {
-    fprintf(stderr, "NULL pointer passed for path @ %s:%d",
-      __FILE__, __LINE__
-    );
-    MPI_Abort(comm, -1);
+  int assert_rc = spath_assert(path != NULL, comm,
+    "NULL pointer passed for path @ %s:%d\n",
+    __FILE__, __LINE__);
+  if (assert_rc) {
+    return SPATH_FAILURE;
   }
 
   /* lookup our rank in comm */
   int rank;
   MPI_Comm_rank(comm, &rank);
 
+  /* as a receiver, verify that we were given an empty path */
+  int components = spath_components(path);
+  assert_rc = spath_assert(rank == root || components == 0, comm,
+    "Non-null path passed as input in receiver to bcast path @ %s:%d\n",
+    __FILE__, __LINE__);
+  if (assert_rc) {
+    return SPATH_FAILURE;
+  }
+
   /* determine number of bytes to send */
   int bytes;
-  int components = spath_components(path);
   if (rank == root) {
     if (components > 0) {
       /* figure out string length of path (including terminating NULL) */
@@ -47,14 +132,6 @@ int spath_bcast(spath* path, int root, MPI_Comm comm)
        * since even an empty string contains at least one byte */
       bytes = 0;
     }
-  } else {
-    /* as a receiver, verify that we were given an empty path */
-    if (components > 0) {
-      fprintf(stderr, "Non-null path passed as input in receiver to bcast path @ %s:%d",
-        __FILE__, __LINE__
-      );
-      MPI_Abort(comm, -1);
-    }
   }
 
   /* broadcast number of bytes in path */
@@ -74,11 +151,11 @@ int spath_bcast(spath* path, int root, MPI_Comm comm)
     /* non-root processes need to allocate an array */
     str = (char*) SPATH_MALLOC((size_t)bytes);
   }
-  if (str == NULL) {
-    fprintf(stderr, "Failed to allocate memory to bcast path @ %s:%d",
-      __FILE__, __LINE__
-    );
-    MPI_Abort(comm, -1);
+  assert_rc = spath_assert(str != NULL, comm,
+    "Failed to allocate memory to bcast path @ %s:%d\n",
+    __FILE__, __LINE__);
+  if (assert_rc) {
+    return SPATH_FAILURE;
   }
 
   /* broadcast the string */

src/spath_mpi.h

@@ -14,6 +14,16 @@
 extern "C" {
 #endif
 
+/* how to behave if an spath_assert condition is found to be false */
+typedef enum {
+  SPATH_ASSERT_ABORT = 1, /* print error message and call abort */
+  SPATH_ASSERT_HANG,      /* print error message and hang with while(1) */
+  SPATH_ASSERT_RETURN,    /* execute allreduce to check on all ranks,
+                           * print error message and return failure on all */
+} spath_assert_mode_t;
+
+extern spath_assert_mode_t spath_assert_mode; /* determines how spath_assert behaves on errors */
+
 #if 0
 /** send/recv path, recv_path should be from spath_new() */
 int spath_sendrecv(