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-rw-r--r--clang/lib/Sema/SemaCast.cpp3
-rw-r--r--clang/lib/Sema/SemaChecking.cpp67
-rw-r--r--clang/lib/Sema/SemaExpr.cpp6
-rw-r--r--clang/lib/Sema/SemaInit.cpp4
4 files changed, 79 insertions, 1 deletions
diff --git a/clang/lib/Sema/SemaCast.cpp b/clang/lib/Sema/SemaCast.cpp
index e83dd071678..e19020c6ade 100644
--- a/clang/lib/Sema/SemaCast.cpp
+++ b/clang/lib/Sema/SemaCast.cpp
@@ -256,6 +256,7 @@ Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
Op.CheckConstCast();
if (Op.SrcExpr.isInvalid())
return ExprError();
+ DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
}
return Op.complete(CXXConstCastExpr::Create(Context, Op.ResultType,
Op.ValueKind, Op.SrcExpr.get(), DestTInfo,
@@ -279,6 +280,7 @@ Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
Op.CheckReinterpretCast();
if (Op.SrcExpr.isInvalid())
return ExprError();
+ DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
}
return Op.complete(CXXReinterpretCastExpr::Create(Context, Op.ResultType,
Op.ValueKind, Op.Kind, Op.SrcExpr.get(),
@@ -291,6 +293,7 @@ Sema::BuildCXXNamedCast(SourceLocation OpLoc, tok::TokenKind Kind,
Op.CheckStaticCast();
if (Op.SrcExpr.isInvalid())
return ExprError();
+ DiscardMisalignedMemberAddress(DestType.getTypePtr(), E);
}
return Op.complete(CXXStaticCastExpr::Create(Context, Op.ResultType,
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index c1781c269d9..6edb251c55b 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -8383,6 +8383,8 @@ void CheckImplicitConversion(Sema &S, Expr *E, QualType T,
DiagnoseNullConversion(S, E, T, CC);
+ S.DiscardMisalignedMemberAddress(Target, E);
+
if (!Source->isIntegerType() || !Target->isIntegerType())
return;
@@ -9453,6 +9455,7 @@ void Sema::CheckCompletedExpr(Expr *E, SourceLocation CheckLoc,
CheckUnsequencedOperations(E);
if (!IsConstexpr && !E->isValueDependent())
CheckForIntOverflow(E);
+ DiagnoseMisalignedMembers();
}
void Sema::CheckBitFieldInitialization(SourceLocation InitLoc,
@@ -10998,3 +11001,67 @@ void Sema::CheckArgumentWithTypeTag(const ArgumentWithTypeTagAttr *Attr,
<< ArgumentExpr->getSourceRange()
<< TypeTagExpr->getSourceRange();
}
+
+void Sema::AddPotentialMisalignedMembers(Expr *E, RecordDecl *RD, ValueDecl *MD,
+ CharUnits Alignment) {
+ MisalignedMembers.emplace_back(E, RD, MD, Alignment);
+}
+
+void Sema::DiagnoseMisalignedMembers() {
+ for (MisalignedMember &m : MisalignedMembers) {
+ Diag(m.E->getLocStart(), diag::warn_taking_address_of_packed_member)
+ << m.MD << m.RD << m.E->getSourceRange();
+ }
+ MisalignedMembers.clear();
+}
+
+void Sema::DiscardMisalignedMemberAddress(const Type *T, Expr *E) {
+ if (!T->isPointerType())
+ return;
+ if (isa<UnaryOperator>(E) &&
+ cast<UnaryOperator>(E)->getOpcode() == UO_AddrOf) {
+ auto *Op = cast<UnaryOperator>(E)->getSubExpr()->IgnoreParens();
+ if (isa<MemberExpr>(Op)) {
+ auto MA = std::find(MisalignedMembers.begin(), MisalignedMembers.end(),
+ MisalignedMember(Op));
+ if (MA != MisalignedMembers.end() &&
+ Context.getTypeAlignInChars(T->getPointeeType()) <= MA->Alignment)
+ MisalignedMembers.erase(MA);
+ }
+ }
+}
+
+void Sema::RefersToMemberWithReducedAlignment(
+ Expr *E,
+ std::function<void(Expr *, RecordDecl *, ValueDecl *, CharUnits)> Action) {
+ const auto *ME = dyn_cast<MemberExpr>(E);
+ while (ME && isa<FieldDecl>(ME->getMemberDecl())) {
+ QualType BaseType = ME->getBase()->getType();
+ if (ME->isArrow())
+ BaseType = BaseType->getPointeeType();
+ RecordDecl *RD = BaseType->getAs<RecordType>()->getDecl();
+
+ ValueDecl *MD = ME->getMemberDecl();
+ bool ByteAligned = Context.getTypeAlignInChars(MD->getType()).isOne();
+ if (ByteAligned) // Attribute packed does not have any effect.
+ break;
+
+ if (!ByteAligned &&
+ (RD->hasAttr<PackedAttr>() || (MD->hasAttr<PackedAttr>()))) {
+ CharUnits Alignment = std::min(Context.getTypeAlignInChars(MD->getType()),
+ Context.getTypeAlignInChars(BaseType));
+ // Notify that this expression designates a member with reduced alignment
+ Action(E, RD, MD, Alignment);
+ break;
+ }
+ ME = dyn_cast<MemberExpr>(ME->getBase());
+ }
+}
+
+void Sema::CheckAddressOfPackedMember(Expr *rhs) {
+ using namespace std::placeholders;
+ RefersToMemberWithReducedAlignment(
+ rhs, std::bind(&Sema::AddPotentialMisalignedMembers, std::ref(*this), _1,
+ _2, _3, _4));
+}
+
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 81b57cad5ec..5a437d279da 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6022,7 +6022,9 @@ Sema::ActOnCastExpr(Scope *S, SourceLocation LParenLoc,
CheckTollFreeBridgeCast(castType, CastExpr);
CheckObjCBridgeRelatedCast(castType, CastExpr);
-
+
+ DiscardMisalignedMemberAddress(castType.getTypePtr(), CastExpr);
+
return BuildCStyleCastExpr(LParenLoc, castTInfo, RParenLoc, CastExpr);
}
@@ -10614,6 +10616,8 @@ QualType Sema::CheckAddressOfOperand(ExprResult &OrigOp, SourceLocation OpLoc) {
if (op->getType()->isObjCObjectType())
return Context.getObjCObjectPointerType(op->getType());
+ CheckAddressOfPackedMember(op);
+
return Context.getPointerType(op->getType());
}
diff --git a/clang/lib/Sema/SemaInit.cpp b/clang/lib/Sema/SemaInit.cpp
index 35accac4972..386c7ab4c08 100644
--- a/clang/lib/Sema/SemaInit.cpp
+++ b/clang/lib/Sema/SemaInit.cpp
@@ -6660,12 +6660,16 @@ InitializationSequence::Perform(Sema &S,
getAssignmentAction(Entity), CCK);
if (CurInitExprRes.isInvalid())
return ExprError();
+
+ S.DiscardMisalignedMemberAddress(Step->Type.getTypePtr(), CurInit.get());
+
CurInit = CurInitExprRes;
if (Step->Kind == SK_ConversionSequenceNoNarrowing &&
S.getLangOpts().CPlusPlus && !CurInit.get()->isValueDependent())
DiagnoseNarrowingInInitList(S, *Step->ICS, SourceType, Entity.getType(),
CurInit.get());
+
break;
}
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