[pure-lang-svn] SF.net SVN: pure-lang:[471] pure/trunk

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

Revision: 471
          http://pure-lang.svn.sourceforge.net/pure-lang/?rev=471&view=rev
Author:   agraef
Date:     2008-08-12 12:56:14 +0000 (Tue, 12 Aug 2008)

Log Message:
-----------
Handle SIGFPE.

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

Modified: pure/trunk/ChangeLog
===================================================================
--- pure/trunk/ChangeLog	2008-08-12 06:49:56 UTC (rev 470)
+++ pure/trunk/ChangeLog	2008-08-12 12:56:14 UTC (rev 471)
@@ -1,5 +1,10 @@
 2008-08-12  Albert Graef  <Dr....@t-...>
 
+	* interpreter.cc (builtin_codegen), runtime.cc(bigint_div,
+	bigint_mod): Handle division by zero by throwing a 'signal SIGFPE'
+	exception. Previously, these would just bail out with an unhandled
+	SIGFPE signal.
+
 	* lexer.ll: Fixed a bug in option parsing of the 'list' command
 	which would cause an option string starting with '-a' to be
 	interpreted as an ordinary argument.

Modified: pure/trunk/interpreter.cc
===================================================================
--- pure/trunk/interpreter.cc	2008-08-12 06:49:56 UTC (rev 470)
+++ pure/trunk/interpreter.cc	2008-08-12 12:56:14 UTC (rev 471)
@@ -263,6 +263,8 @@
 		 "pure_catch",      "expr*",  2, "expr*", "expr*");
   declare_extern((void*)pure_throw,
 		 "pure_throw",      "void",   1, "expr*");
+  declare_extern((void*)pure_sigfpe,
+		 "pure_sigfpe",     "void",   0);
 
   declare_extern((void*)pure_new,
 		 "pure_new",        "expr*",  1, "expr*");
@@ -3652,11 +3654,43 @@
 	return b.CreateSub(u, v);
       else if (f.ftag() == symtab.mult_sym().f)
 	return b.CreateMul(u, v);
-      else if (f.ftag() == symtab.div_sym().f)
-	return b.CreateSDiv(u, v);
-      else if (f.ftag() == symtab.mod_sym().f)
-	return b.CreateSRem(u, v);
-      else {
+      else if (f.ftag() == symtab.div_sym().f) {
+	// catch division by zero
+	if (x.xval2().tag() == EXPR::INT && x.xval2().ival() == 0) {
+	  b.CreateCall(module->getFunction("pure_sigfpe"));
+	  return v;
+	} else {
+	  BasicBlock *okbb = BasicBlock::Create("ok");
+	  BasicBlock *errbb = BasicBlock::Create("err");
+	  Value *cmp = b.CreateICmpEQ(v, Zero);
+	  b.CreateCondBr(cmp, errbb, okbb);
+	  act_env().f->getBasicBlockList().push_back(errbb);
+	  b.SetInsertPoint(errbb);
+	  b.CreateCall(module->getFunction("pure_sigfpe"));
+	  b.CreateRet(NullExprPtr);
+	  act_env().f->getBasicBlockList().push_back(okbb);
+	  b.SetInsertPoint(okbb);
+	  return b.CreateSDiv(u, v);
+	}
+      } else if (f.ftag() == symtab.mod_sym().f) {
+	// catch division by zero
+	if (x.xval2().tag() == EXPR::INT && x.xval2().ival() == 0) {
+	  b.CreateCall(module->getFunction("pure_sigfpe"));
+	  return v;
+	} else {
+	  BasicBlock *okbb = BasicBlock::Create("ok");
+	  BasicBlock *errbb = BasicBlock::Create("err");
+	  Value *cmp = b.CreateICmpEQ(v, Zero);
+	  b.CreateCondBr(cmp, errbb, okbb);
+	  act_env().f->getBasicBlockList().push_back(errbb);
+	  b.SetInsertPoint(errbb);
+	  b.CreateCall(module->getFunction("pure_sigfpe"));
+	  b.CreateRet(NullExprPtr);
+	  act_env().f->getBasicBlockList().push_back(okbb);
+	  b.SetInsertPoint(okbb);
+	  return b.CreateSRem(u, v);
+	}
+      } else {
 	assert(0 && "error in type checker");
 	return 0;
       }

Modified: pure/trunk/runtime.cc
===================================================================
--- pure/trunk/runtime.cc	2008-08-12 06:49:56 UTC (rev 470)
+++ pure/trunk/runtime.cc	2008-08-12 12:56:14 UTC (rev 471)
@@ -1289,7 +1289,15 @@
   }
 }
 
+#include <signal.h>
+
 extern "C"
+void pure_sigfpe(void)
+{
+  pure_throw(signal_exception(SIGFPE));
+}
+
+extern "C"
 pure_expr *pure_catch(pure_expr *h, pure_expr *x)
 {
   char test;
@@ -1952,9 +1960,12 @@
   return u;
 }
 
+// These raise a SIGFPE signal exception for division by zero.
+
 extern "C"
 pure_expr *bigint_div(mpz_t x, mpz_t y)
 {
+  if (mpz_sgn(y) == 0) pure_sigfpe();
   pure_expr *u = pure_bigint(0, 0);
   mpz_t& z = u->data.z;
   mpz_tdiv_q(z, x, y);
@@ -1964,6 +1975,7 @@
 extern "C"
 pure_expr *bigint_mod(mpz_t x, mpz_t y)
 {
+  if (mpz_sgn(y) == 0) pure_sigfpe();
   pure_expr *u = pure_bigint(0, 0);
   mpz_t& z = u->data.z;
   mpz_tdiv_r(z, x, y);

Modified: pure/trunk/runtime.h
===================================================================
--- pure/trunk/runtime.h	2008-08-12 06:49:56 UTC (rev 470)
+++ pure/trunk/runtime.h	2008-08-12 12:56:14 UTC (rev 471)
@@ -340,6 +340,11 @@
 
 void pure_throw(pure_expr* e);
 
+/* Throw a 'signal SIGFPE' exception. This is used to signal division by
+   zero. */
+
+void pure_sigfpe(void);
+
 /* Execute a parameterless fbox x and return its result. If an exception
    occurs while x is executed, apply h to the value of the exception
    instead. */


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