[pure-lang-svn] SF.net SVN: pure-lang: [36] pure/trunk

[<ag...@us...>]

Revision: 36
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=36&view=rev
Author:   agraef
Date:     2008-05-03 03:29:01 -0700 (Sat, 03 May 2008)

Log Message:
-----------
Fixed premature garbage collection of arguments in external wrapper code.

Modified Paths:
--------------
    pure/trunk/ChangeLog
    pure/trunk/interpreter.cc

Modified: pure/trunk/ChangeLog
===================================================================
--- pure/trunk/ChangeLog	2008-05-03 10:05:43 UTC (rev 35)
+++ pure/trunk/ChangeLog	2008-05-03 10:29:01 UTC (rev 36)
@@ -1,6 +1,13 @@
 2008-05-03  Albert Graef  <Dr....@t-...>
 
-	* test/test4.pure: Disable tail call checks, as they may fail on
+	* interpreter.cc (declare_extern): Fixed a bug in the generated
+	wrapper code for external calls, which caused function arguments
+	to be garbage-collected prematurely, when they were still needed
+	to create the default value, in the case of external calls
+	returning a null expression pointer to indicate failure. Reported
+	by Eddie Rucker.
+
+	* test/test4.pure: Disabled tail call checks, as they may fail on
 	some platforms. Reported by Ryan Schmidt.
 
 	* test/test1.pure: Corrected fact3 example, added test cases.

Modified: pure/trunk/interpreter.cc
===================================================================
--- pure/trunk/interpreter.cc	2008-05-03 10:05:43 UTC (rev 35)
+++ pure/trunk/interpreter.cc	2008-05-03 10:29:01 UTC (rev 36)
@@ -2405,19 +2405,8 @@
   }
   // call the function
   Value* u = b.CreateCall(g, unboxed.begin(), unboxed.end());
-  // free temporaries and arguments
+  // free temporaries
   if (temps) b.CreateCall(module->getFunction("pure_free_cstrings"));
-  if (n == 1)
-    b.CreateCall(module->getFunction("pure_free"), args[0]);
-  else if (n > 0) {
-    vector<Value*> freeargs(n+2);
-    freeargs[0] = NullExprPtr;
-    for (size_t i = 0; i < n; i++)
-      freeargs[i+1] = args[i];
-    freeargs[n+1] = NullExprPtr;
-    b.CreateCall(module->getFunction("pure_free_args"),
-		 freeargs.begin(), freeargs.end());
-  }
   // box the result
   if (type == Type::VoidTy)
     u = b.CreateCall(module->getFunction("pure_const"),
@@ -2456,6 +2445,18 @@
     u = b.CreateCall(module->getFunction("pure_pointer"), u);
   else
     assert(0 && "invalid C type");
+  // free arguments (we do that here so that the arguments don't get freed
+  // before we know that we don't need them anymore)
+  if (n > 0) {
+    vector<Value*> freeargs(n+2);
+    freeargs[0] = u;
+    for (size_t i = 0; i < n; i++)
+      freeargs[i+1] = args[i];
+    freeargs[n+1] = NullExprPtr;
+    b.CreateCall(module->getFunction("pure_free_args"),
+		 freeargs.begin(), freeargs.end());
+    b.CreateCall(module->getFunction("pure_unref"), u);
+  }
   b.CreateRet(u);
   // The call failed. Provide a default value.
   f->getBasicBlockList().push_back(failedbb);


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