steven_wu updated this revision to Diff 49549.
steven_wu added a comment.
I did some more digging of the issue. It seems ObjCSubscriptRefExpr always
rebuilds and hinds both base and key behind OpaqueValueExpr. See
ObjCSubscriptOpBuilder::rebuildAndCaptureObject so it looks the AST generated
is intentional. If that is the case, Richard's suggestion is the best fix I
can think about. Update the patch to reflect the suggestion.
http://reviews.llvm.org/D17627
Files:
lib/Sema/SemaStmt.cpp
test/SemaObjC/warn-loop-analysis.m
Index: test/SemaObjC/warn-loop-analysis.m
===================================================================
--- /dev/null
+++ test/SemaObjC/warn-loop-analysis.m
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -fsyntax-only -Wloop-analysis -verify %s
+// expected-no-diagnostics
+
+@interface MyArray
+- (id)objectAtIndexedSubscript:(unsigned int)idx;
+@end
+
+// Do not warn on objc classes has objectAtIndexedSubscript method.
+MyArray *test;
+void foo()
+{
+ unsigned int i;
+ for (i = 42; i > 0;) // No warnings here
+ (void)test[--i];
+}
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -1440,6 +1440,18 @@
FoundDecl = true;
}
+ void VisitObjCSubscriptRefExpr(ObjCSubscriptRefExpr *E) {
+ // ObjCSubscriptRefExpr always converts its subexpressions behind OVE.
+ // Look pass OVE in case it has the only reference to Decl.
+ if (auto *OVE = dyn_cast<OpaqueValueExpr>(E->getKeyExpr())) {
+ if (Expr *Key = OVE->getSourceExpr())
+ Visit(Key);
+ } else
+ Visit(E->getKeyExpr());
+
+ Visit(E->getBaseExpr());
+ }
+
bool FoundDeclInUse() { return FoundDecl; }
}; // end class DeclMatcher
Index: test/SemaObjC/warn-loop-analysis.m
===================================================================
--- /dev/null
+++ test/SemaObjC/warn-loop-analysis.m
@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -fsyntax-only -Wloop-analysis -verify %s
+// expected-no-diagnostics
+
+@interface MyArray
+- (id)objectAtIndexedSubscript:(unsigned int)idx;
+@end
+
+// Do not warn on objc classes has objectAtIndexedSubscript method.
+MyArray *test;
+void foo()
+{
+ unsigned int i;
+ for (i = 42; i > 0;) // No warnings here
+ (void)test[--i];
+}
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -1440,6 +1440,18 @@
FoundDecl = true;
}
+ void VisitObjCSubscriptRefExpr(ObjCSubscriptRefExpr *E) {
+ // ObjCSubscriptRefExpr always converts its subexpressions behind OVE.
+ // Look pass OVE in case it has the only reference to Decl.
+ if (auto *OVE = dyn_cast<OpaqueValueExpr>(E->getKeyExpr())) {
+ if (Expr *Key = OVE->getSourceExpr())
+ Visit(Key);
+ } else
+ Visit(E->getKeyExpr());
+
+ Visit(E->getBaseExpr());
+ }
+
bool FoundDeclInUse() { return FoundDecl; }
}; // end class DeclMatcher
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