From: David Malcolm <dmalcolm@redhat.com>
Date: Thu, 24 Aug 2023 14:24:39 +0000 (-0400)
Subject: analyzer: reimplement kf_memcpy_memmove
X-Git-Tag: basepoints/gcc-15~6674
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8556d0014acfa3ed8435f405984a3b8f38996819;p=thirdparty%2Fgcc.git

analyzer: reimplement kf_memcpy_memmove

gcc/analyzer/ChangeLog:
	* kf.cc (kf_memcpy_memmove::impl_call_pre): Reimplement using
	region_model::copy_bytes.
	* region-model.cc (region_model::read_bytes): New.
	(region_model::copy_bytes): New.
	* region-model.h (region_model::read_bytes): New decl.
	(region_model::copy_bytes): New decl.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>
---

diff --git a/gcc/analyzer/kf.cc b/gcc/analyzer/kf.cc
index 6b33cd159dac..3eddbe200387 100644
--- a/gcc/analyzer/kf.cc
+++ b/gcc/analyzer/kf.cc
@@ -541,7 +541,6 @@ kf_memcpy_memmove::impl_call_pre (const call_details &cd) const
   const svalue *num_bytes_sval = cd.get_arg_svalue (2);
 
   region_model *model = cd.get_model ();
-  region_model_manager *mgr = cd.get_manager ();
 
   const region *dest_reg
     = model->deref_rvalue (dest_ptr_sval, cd.get_arg_tree (0), cd.get_ctxt ());
@@ -550,15 +549,10 @@ kf_memcpy_memmove::impl_call_pre (const call_details &cd) const
 
   cd.maybe_set_lhs (dest_ptr_sval);
 
-  const region *sized_src_reg
-    = mgr->get_sized_region (src_reg, NULL_TREE, num_bytes_sval);
-  const region *sized_dest_reg
-    = mgr->get_sized_region (dest_reg, NULL_TREE, num_bytes_sval);
-  const svalue *src_contents_sval
-    = model->get_store_value (sized_src_reg, cd.get_ctxt ());
-  model->check_for_poison (src_contents_sval, cd.get_arg_tree (1),
-			   sized_src_reg, cd.get_ctxt ());
-  model->set_value (sized_dest_reg, src_contents_sval, cd.get_ctxt ());
+  model->copy_bytes (dest_reg,
+		     src_reg, cd.get_arg_tree (1),
+		     num_bytes_sval,
+		     cd.get_ctxt ());
 }
 
 /* Handler for "memset" and "__builtin_memset".  */
diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index 1fe66f4719fa..00c306ab7dae 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -3794,6 +3794,41 @@ region_model::write_bytes (const region *dest_reg,
   set_value (sized_dest_reg, sval, ctxt);
 }
 
+/* Read NUM_BYTES_SVAL from SRC_REG.
+   Use CTXT to report any warnings associated with the copy
+   (e.g. out-of-bounds reads, copying of uninitialized values, etc).  */
+
+const svalue *
+region_model::read_bytes (const region *src_reg,
+			  tree src_ptr_expr,
+			  const svalue *num_bytes_sval,
+			  region_model_context *ctxt) const
+{
+  const region *sized_src_reg
+    = m_mgr->get_sized_region (src_reg, NULL_TREE, num_bytes_sval);
+  const svalue *src_contents_sval = get_store_value (sized_src_reg, ctxt);
+  check_for_poison (src_contents_sval, src_ptr_expr,
+		    sized_src_reg, ctxt);
+  return src_contents_sval;
+}
+
+/* Copy NUM_BYTES_SVAL bytes from SRC_REG to DEST_REG.
+   Use CTXT to report any warnings associated with the copy
+   (e.g. out-of-bounds reads/writes, copying of uninitialized values,
+   etc).  */
+
+void
+region_model::copy_bytes (const region *dest_reg,
+			  const region *src_reg,
+			  tree src_ptr_expr,
+			  const svalue *num_bytes_sval,
+			  region_model_context *ctxt)
+{
+  const svalue *data_sval
+    = read_bytes (src_reg, src_ptr_expr, num_bytes_sval, ctxt);
+  write_bytes (dest_reg, num_bytes_sval, data_sval, ctxt);
+}
+
 /* Mark REG as having unknown content.  */
 
 void
diff --git a/gcc/analyzer/region-model.h b/gcc/analyzer/region-model.h
index 41df1885ad5b..b1c705e22c28 100644
--- a/gcc/analyzer/region-model.h
+++ b/gcc/analyzer/region-model.h
@@ -371,6 +371,15 @@ class region_model
 		    const svalue *num_bytes_sval,
 		    const svalue *sval,
 		    region_model_context *ctxt);
+  const svalue *read_bytes (const region *src_reg,
+			    tree src_ptr_expr,
+			    const svalue *num_bytes_sval,
+			    region_model_context *ctxt) const;
+  void copy_bytes (const region *dest_reg,
+		   const region *src_reg,
+		   tree src_ptr_expr,
+		   const svalue *num_bytes_sval,
+		   region_model_context *ctxt);
   void mark_region_as_unknown (const region *reg, uncertainty_t *uncertainty);
 
   tristate eval_condition (const svalue *lhs,