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Audit op1_range and op2_range for undefined LHS.

Message ID 16763009-abeb-5785-80fc-40cd755fef0c@redhat.com
State New
Headers show
Series Audit op1_range and op2_range for undefined LHS. | expand

Commit Message

Andrew MacLeod Sept. 29, 2022, 10:35 p.m. UTC 
If the LHS is undefined, GORI should not proceed further.  There are a 
few places where this happens, and a few potential traps. Most haven't 
been an issue up until now, but forthcoming changes tend to cause them 
to trigger more often.

Bootstrapped on x86_64-pc-linux-gnu with no regressions.  Pushed.

Andrew
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Patch

From beb135aaabac4771a405b8d41ad37285ee6f872e Mon Sep 17 00:00:00 2001
From: Andrew MacLeod <amacleod@redhat.com>
Date: Tue, 27 Sep 2022 19:12:06 -0400
Subject: [PATCH 2/6] Audit op1_range and op2_range for undefined LHS.

If the LHS is undefined, GORI should cease looking. There are numerous
places where this happens, and a few potential traps.

	* range-op.cc (operator_minus::op2_range): Check for undefined.
	(operator_mult::op1_range): Ditto.
	(operator_exact_divide::op1_range): Ditto.
	(operator_lshift::op1_range): Ditto.
	(operator_rshift::op1_range): Ditto.
	(operator_cast::op1_range): Ditto.
	(operator_bitwise_and::op1_range): Ditto.
	(operator_bitwise_or::op1_range): Ditto.
	(operator_trunc_mod::op1_range): Ditto.
	(operator_trunc_mod::op2_range): Ditto.
	(operator_bitwise_not::op1_range): Ditto.
	(pointer_or_operator::op1_range): Ditto.
	(range_op_handler::op1_range): Ditto.
	(range_op_handler::op2_range): Ditto.
---
 gcc/range-op.cc | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/gcc/range-op.cc b/gcc/range-op.cc
index 072ebd32109..9bb04c361d0 100644
--- a/gcc/range-op.cc
+++ b/gcc/range-op.cc
@@ -1481,6 +1481,8 @@  operator_minus::op2_range (irange &r, tree type,
 			   const irange &op1,
 			   relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   return fold_range (r, type, op1, lhs);
 }
 
@@ -1650,6 +1652,8 @@  operator_mult::op1_range (irange &r, tree type,
 			  relation_kind rel ATTRIBUTE_UNUSED) const
 {
   tree offset;
+  if (lhs.undefined_p ())
+    return false;
 
   // We can't solve 0 = OP1 * N by dividing by N with a wrapping type.
   // For example: For 0 = OP1 * 2, OP1 could be 0, or MAXINT, whereas
@@ -1902,6 +1906,8 @@  operator_exact_divide::op1_range (irange &r, tree type,
 				  const irange &op2,
 				  relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   tree offset;
   // [2, 4] = op1 / [3,3]   since its exact divide, no need to worry about
   // remainders in the endpoints, so op1 = [2,4] * [3,3] = [6,12].
@@ -2111,6 +2117,8 @@  operator_lshift::op1_range (irange &r,
 			    const irange &op2,
 			    relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   tree shift_amount;
 
   if (!lhs.contains_p (build_zero_cst (type)))
@@ -2183,6 +2191,8 @@  operator_rshift::op1_range (irange &r,
 			    relation_kind rel ATTRIBUTE_UNUSED) const
 {
   tree shift;
+  if (lhs.undefined_p ())
+    return false;
   if (op2.singleton_p (&shift))
     {
       // Ignore nonsensical shifts.
@@ -2401,6 +2411,8 @@  operator_cast::op1_range (irange &r, tree type,
 			  const irange &op2,
 			  relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   tree lhs_type = lhs.type ();
   gcc_checking_assert (types_compatible_p (op2.type(), type));
 
@@ -2936,6 +2948,8 @@  operator_bitwise_and::op1_range (irange &r, tree type,
 				 const irange &op2,
 				 relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   if (types_compatible_p (type, boolean_type_node))
     return op_logical_and.op1_range (r, type, lhs, op2);
 
@@ -3112,6 +3126,8 @@  operator_bitwise_or::op1_range (irange &r, tree type,
 				const irange &op2,
 				relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   // If this is really a logical wi_fold, call that.
   if (types_compatible_p (type, boolean_type_node))
     return op_logical_or.op1_range (r, type, lhs, op2);
@@ -3361,6 +3377,8 @@  operator_trunc_mod::op1_range (irange &r, tree type,
 			       const irange &,
 			       relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   // PR 91029.
   signop sign = TYPE_SIGN (type);
   unsigned prec = TYPE_PRECISION (type);
@@ -3385,6 +3403,8 @@  operator_trunc_mod::op2_range (irange &r, tree type,
 			       const irange &,
 			       relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   // PR 91029.
   signop sign = TYPE_SIGN (type);
   unsigned prec = TYPE_PRECISION (type);
@@ -3513,6 +3533,8 @@  operator_bitwise_not::op1_range (irange &r, tree type,
 				 const irange &op2,
 				 relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   if (types_compatible_p (type, boolean_type_node))
     return op_logical_not.op1_range (r, type, lhs, op2);
 
@@ -3999,6 +4021,8 @@  pointer_or_operator::op1_range (irange &r, tree type,
 				const irange &op2 ATTRIBUTE_UNUSED,
 				relation_kind rel ATTRIBUTE_UNUSED) const
 {
+  if (lhs.undefined_p ())
+    return false;
   if (lhs.zero_p ())
     {
       tree zero = build_zero_cst (type);
@@ -4230,6 +4254,9 @@  range_op_handler::op1_range (vrange &r, tree type,
 			     relation_kind rel) const
 {
   gcc_checking_assert (m_valid);
+
+  if (lhs.undefined_p ())
+    return false;
   if (m_int)
     return m_int->op1_range (as_a <irange> (r), type,
 			     as_a <irange> (lhs),
@@ -4251,6 +4278,8 @@  range_op_handler::op2_range (vrange &r, tree type,
 			     relation_kind rel) const
 {
   gcc_checking_assert (m_valid);
+  if (lhs.undefined_p ())
+    return false;
   if (m_int)
     return m_int->op2_range (as_a <irange> (r), type,
 			     as_a <irange> (lhs),
-- 
2.37.3