Merge remote-tracking branch 'origin/swift-3.1-branch' into stable
* origin/swift-3.1-branch:
[Sema] Teach -Wcast-align to look at the aligned attribute of the declared variables.
diff --git a/lib/Sema/SemaChecking.cpp b/lib/Sema/SemaChecking.cpp
index e36fb91..6759a61 100644
--- a/lib/Sema/SemaChecking.cpp
+++ b/lib/Sema/SemaChecking.cpp
@@ -9727,6 +9727,19 @@
return HasInvalidParm;
}
+/// A helper function to get the alignment of a Decl referred to by DeclRefExpr
+/// or MemberExpr.
+static CharUnits getDeclAlign(Expr *E, CharUnits TypeAlign,
+ ASTContext &Context) {
+ if (const auto *DRE = dyn_cast<DeclRefExpr>(E))
+ return Context.getDeclAlign(DRE->getDecl());
+
+ if (const auto *ME = dyn_cast<MemberExpr>(E))
+ return Context.getDeclAlign(ME->getMemberDecl());
+
+ return TypeAlign;
+}
+
/// CheckCastAlign - Implements -Wcast-align, which warns when a
/// pointer cast increases the alignment requirements.
void Sema::CheckCastAlign(Expr *Op, QualType T, SourceRange TRange) {
@@ -9761,6 +9774,15 @@
if (SrcPointee->isIncompleteType()) return;
CharUnits SrcAlign = Context.getTypeAlignInChars(SrcPointee);
+
+ if (auto *CE = dyn_cast<CastExpr>(Op)) {
+ if (CE->getCastKind() == CK_ArrayToPointerDecay)
+ SrcAlign = getDeclAlign(CE->getSubExpr(), SrcAlign, Context);
+ } else if (auto *UO = dyn_cast<UnaryOperator>(Op)) {
+ if (UO->getOpcode() == UO_AddrOf)
+ SrcAlign = getDeclAlign(UO->getSubExpr(), SrcAlign, Context);
+ }
+
if (SrcAlign >= DestAlign) return;
Diag(TRange.getBegin(), diag::warn_cast_align)
diff --git a/test/Sema/warn-cast-align.c b/test/Sema/warn-cast-align.c
index 9d64699..e8f85bc 100644
--- a/test/Sema/warn-cast-align.c
+++ b/test/Sema/warn-cast-align.c
@@ -39,3 +39,23 @@
void test3(char *P) {
struct B *b = (struct B*) P;
}
+
+// Do not issue a warning. The aligned attribute changes the alignment of the
+// variables and fields.
+char __attribute__((aligned(4))) a[16];
+
+struct S0 {
+ char a[16];
+};
+
+struct S {
+ char __attribute__((aligned(4))) a[16];
+ struct S0 __attribute__((aligned(4))) s0;
+};
+
+void test4() {
+ struct S s;
+ int *i = (int *)s.a;
+ i = (int *)&s.s0;
+ i = (int *)a;
+}
