[pure-lang-svn] SF.net SVN: pure-lang:[463] pure/trunk

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

Revision: 463
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=463&view=rev
Author:   agraef
Date:     2008-08-11 10:01:55 +0000 (Mon, 11 Aug 2008)

Log Message:
-----------
More optimizations of toplevel expressions to avoid unnecessary evaluations of constants.

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

Modified: pure/trunk/interpreter.cc
===================================================================
--- pure/trunk/interpreter.cc	2008-08-10 21:33:41 UTC (rev 462)
+++ pure/trunk/interpreter.cc	2008-08-11 10:01:55 UTC (rev 463)
@@ -3076,6 +3076,8 @@
     return pure_string_dup(x.sval());
   case EXPR::PTR:
     return pure_pointer(x.pval());
+  case EXPR::APP:
+    return const_app_value(x);
   default: {
     exprl xs;
     if (x.tag() > 0) {
@@ -3114,6 +3116,42 @@
   }
 }
 
+pure_expr *interpreter::const_app_value(expr x)
+{
+  if (x.tag() == EXPR::APP) {
+    pure_expr *f = 0, *y = 0;
+    if ((f = const_app_value(x.xval1())) && (y = const_value(x.xval2())))
+      return pure_app(f, y);
+    else {
+      if (f) pure_freenew(f);
+      return 0;
+    }
+  } else if (x.tag() > 0) {
+    env::const_iterator it = globenv.find(x.tag());
+    map<int32_t,GlobalVar>::iterator v;
+    if (externals.find(x.tag()) != externals.end())
+      return 0;
+    else if (it == globenv.end())
+      // unbound symbol
+      return pure_const(x.tag());
+    else if (it->second.t == env_info::fvar &&
+	     (v = globalvars.find(x.tag())) != globalvars.end()) {
+      // variable value
+      pure_expr *y = v->second.x;
+      // walk down the spine, if any
+      while (y->tag == EXPR::APP) y = y->data.x[0];
+      // check if we got a closure subject to evaluation
+      if (y->tag >= 0 && y->data.clos)
+	return 0;
+      else
+	// not a callable closure, so it must be a constructor term
+	return v->second.x;
+    } else
+      return 0;
+  } else
+    return 0;
+}
+
 pure_expr *interpreter::doeval(expr x, pure_expr*& e)
 {
   char test;

Modified: pure/trunk/interpreter.hh
===================================================================
--- pure/trunk/interpreter.hh	2008-08-10 21:33:41 UTC (rev 462)
+++ pure/trunk/interpreter.hh	2008-08-11 10:01:55 UTC (rev 463)
@@ -494,6 +494,7 @@
   Env& act_env() { assert(!envstk.empty()); return *envstk.front(); }
   Builder& act_builder() { return act_env().builder; }
   pure_expr *const_value(expr x);
+  pure_expr *const_app_value(expr x);
   pure_expr *doeval(expr x, pure_expr*& e);
   pure_expr *dodefn(env vars, expr lhs, expr rhs, pure_expr*& e);
   llvm::Value *codegen(expr x);


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