[PATCH] D83317: [Sema] Teach -Wcast-align to compute alignment of CXXThisExpr
Akira Hatanaka via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Tue Jul 7 08:53:00 PDT 2020
ahatanak created this revision.
ahatanak added reviewers: rjmccall, jyknight.
ahatanak added a project: clang.
Herald added subscribers: ributzka, dexonsmith, jkorous.
This fixes https://bugs.llvm.org/show_bug.cgi?id=46605.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D83317
Files:
clang/lib/Sema/SemaChecking.cpp
clang/test/SemaCXX/warn-cast-align.cpp
Index: clang/test/SemaCXX/warn-cast-align.cpp
===================================================================
--- clang/test/SemaCXX/warn-cast-align.cpp
+++ clang/test/SemaCXX/warn-cast-align.cpp
@@ -44,9 +44,16 @@
c = IntPtr(P);
}
+struct __attribute__((aligned(16))) AlignedS {
+ char m[16];
+};
+
struct __attribute__((aligned(16))) A {
char m0[16];
char m1[16];
+ AlignedS *getAlignedS() {
+ return (AlignedS *)m1;
+ }
};
struct B0 {
@@ -92,6 +99,9 @@
struct D5 : virtual D0 {
char m0[16];
+ AlignedS *get() {
+ return (AlignedS *)m0; // expected-warning {{cast from 'char *' to 'AlignedS *'}}
+ }
};
struct D6 : virtual D5 {
Index: clang/lib/Sema/SemaChecking.cpp
===================================================================
--- clang/lib/Sema/SemaChecking.cpp
+++ clang/lib/Sema/SemaChecking.cpp
@@ -13487,12 +13487,14 @@
}
case Stmt::MemberExprClass: {
auto *ME = cast<MemberExpr>(E);
- if (ME->isArrow())
- break;
auto *FD = dyn_cast<FieldDecl>(ME->getMemberDecl());
if (!FD || FD->getType()->isReferenceType())
break;
- auto P = getBaseAlignmentAndOffsetFromLValue(ME->getBase(), Ctx);
+ Optional<std::pair<CharUnits, CharUnits>> P;
+ if (ME->isArrow())
+ P = getBaseAlignmentAndOffsetFromPtr(ME->getBase(), Ctx);
+ else
+ P = getBaseAlignmentAndOffsetFromLValue(ME->getBase(), Ctx);
if (!P)
break;
const ASTRecordLayout &Layout = Ctx.getASTRecordLayout(FD->getParent());
@@ -13556,6 +13558,11 @@
}
break;
}
+ case Stmt::CXXThisExprClass: {
+ auto *RD = E->getType()->getPointeeType()->getAsCXXRecordDecl();
+ CharUnits Alignment = Ctx.getASTRecordLayout(RD).getNonVirtualAlignment();
+ return std::make_pair(Alignment, CharUnits::Zero());
+ }
case Stmt::UnaryOperatorClass: {
auto *UO = cast<UnaryOperator>(E);
if (UO->getOpcode() == UO_AddrOf)
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