[PATCH] D69664: [Diagnostics] Teach -Wnull-dereference about address_space attribute

[Dávid Bolvanský via Phabricator via cfe-commits]

xbolva00 created this revision.
xbolva00 added reviewers: aaron.ballman, rsmith.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

Clang should not warn for:
test.c:2:12: warning: indirection of non-volatile null pointer will be deleted,

    not trap [-Wnull-dereference]
  return *(int __attribute__((address_space(256))) *) 0;
         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Solves PR42292.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D69664

Files:
  clang/lib/Sema/SemaExpr.cpp
  clang/test/Sema/exprs.c


Index: clang/test/Sema/exprs.c
===================================================================
--- clang/test/Sema/exprs.c
+++ clang/test/Sema/exprs.c
@@ -179,11 +179,13 @@
   test18_e(); // expected-error {{too few arguments to function call, expected at least 2, have 0}}
 }
 
+typedef int __attribute__((address_space(256))) int_as_256;
 // PR7569
 void test19() {
   *(int*)0 = 0;   // expected-warning {{indirection of non-volatile null pointer}} \
                   // expected-note {{consider using __builtin_trap}}
   *(volatile int*)0 = 0;  // Ok.
+   *(int __attribute__((address_space(256))) *)0 = 0; // Ok.
 
   // rdar://9269271
   int x = *(int*)0;  // expected-warning {{indirection of non-volatile null pointer}} \
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -483,15 +483,17 @@
   // only handles the pattern "*null", which is a very syntactic check.
   if (UnaryOperator *UO = dyn_cast<UnaryOperator>(E->IgnoreParenCasts()))
     if (UO->getOpcode() == UO_Deref &&
-        UO->getSubExpr()->IgnoreParenCasts()->
-          isNullPointerConstant(S.Context, Expr::NPC_ValueDependentIsNotNull) &&
+        !isTargetAddressSpace(
+            UO->getSubExpr()->getType()->getPointeeType().getAddressSpace()) &&
+        UO->getSubExpr()->IgnoreParenCasts()->isNullPointerConstant(
+            S.Context, Expr::NPC_ValueDependentIsNotNull) &&
         !UO->getType().isVolatileQualified()) {
-    S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
-                          S.PDiag(diag::warn_indirection_through_null)
-                            << UO->getSubExpr()->getSourceRange());
-    S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
-                        S.PDiag(diag::note_indirection_through_null));
-  }
+      S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
+                            S.PDiag(diag::warn_indirection_through_null)
+                                << UO->getSubExpr()->getSourceRange());
+      S.DiagRuntimeBehavior(UO->getOperatorLoc(), UO,
+                            S.PDiag(diag::note_indirection_through_null));
+    }
 }
 
 static void DiagnoseDirectIsaAccess(Sema &S, const ObjCIvarRefExpr *OIRE,


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D69664.227285.patch
Type: text/x-patch
Size: 2281 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20191031/5e118f8a/attachment.bin>