This patch is motivated by numerous strict-aliasing warnings when compiling
clang as a Release build.
The big change is that all AST nodes (subclasses of Stmt) whose children are
Expr* store their children as Stmt* or arrays of Stmt*. This is to remove
strict-aliasing warnings when using StmtIterator. None of the interfaces of any
of the classes have changed (except those with arg_iterators, see below), as the
accessor methods introduce the needed casts (via cast<>). While this extra
casting may seem cumbersome, it actually adds some important sanity checks
throughout the codebase, as clients using StmtIterator can potentially overwrite
children that are expected to be Expr* with Stmt* (that aren't Expr*). The casts
provide extra sanity checks that are operational in debug builds to catch
invariant violations such as these.
For classes that have arg_iterators (e.g., CallExpr), the definition of
arg_iterator has been replaced. Instead of it being Expr**, it is an actual
class (called ExprIterator) that wraps a Stmt**, and provides the necessary
operators for iteration. The nice thing about this class is that it also uses
cast<> to type-checking, which introduces extra sanity checks throughout the
codebase that are useful for debugging.
A few of the CodeGen functions that use arg_iterator (especially from
OverloadExpr) have been modified to take begin and end iterators instead of a
base Expr** and the number of arguments. This matches more with the abstraction
of iteration. This still needs to be cleaned up a little bit, as clients expect
that ExprIterator is a RandomAccessIterator (which we may or may not wish to
allow for efficiency of representation).
This is a fairly large patch. It passes the tests (except CodeGen/bitfield.c,
which was already broken) on both a Debug and Release build, but it should
obviously be reviewed.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@52378 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 78c3050..496afd6 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -92,7 +92,7 @@
CallExpr::CallExpr(Expr *fn, Expr **args, unsigned numargs, QualType t,
SourceLocation rparenloc)
: Expr(CallExprClass, t), NumArgs(numargs) {
- SubExprs = new Expr*[numargs+1];
+ SubExprs = new Stmt*[numargs+1];
SubExprs[FN] = fn;
for (unsigned i = 0; i != numargs; ++i)
SubExprs[i+ARGS_START] = args[i];
@@ -115,7 +115,7 @@
}
// Otherwise, we are growing the # arguments. New an bigger argument array.
- Expr **NewSubExprs = new Expr*[NumArgs+1];
+ Stmt **NewSubExprs = new Stmt*[NumArgs+1];
// Copy over args.
for (unsigned i = 0; i != getNumArgs()+ARGS_START; ++i)
NewSubExprs[i] = SubExprs[i];
@@ -1109,7 +1109,7 @@
: Expr(ObjCMessageExprClass, retType), SelName(selInfo),
MethodProto(mproto) {
NumArgs = nargs;
- SubExprs = new Expr*[NumArgs+1];
+ SubExprs = new Stmt*[NumArgs+1];
SubExprs[RECEIVER] = receiver;
if (NumArgs) {
for (unsigned i = 0; i != NumArgs; ++i)
@@ -1128,7 +1128,7 @@
: Expr(ObjCMessageExprClass, retType), SelName(selInfo),
MethodProto(mproto) {
NumArgs = nargs;
- SubExprs = new Expr*[NumArgs+1];
+ SubExprs = new Stmt*[NumArgs+1];
SubExprs[RECEIVER] = (Expr*) ((uintptr_t) clsName | 0x1);
if (NumArgs) {
for (unsigned i = 0; i != NumArgs; ++i)
@@ -1184,7 +1184,7 @@
assert(Opc == OffsetOf && "Unary operator not offsetof!");
unsigned CharSize = C.Target.getCharWidth();
- return ::evaluateOffsetOf(C, Val) / CharSize;
+ return ::evaluateOffsetOf(C, cast<Expr>(Val)) / CharSize;
}
//===----------------------------------------------------------------------===//
@@ -1196,22 +1196,12 @@
Stmt::child_iterator DeclRefExpr::child_end() { return child_iterator(); }
// ObjCIvarRefExpr
-Stmt::child_iterator ObjCIvarRefExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Base);
-}
-
-Stmt::child_iterator ObjCIvarRefExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Base)+1;
-}
+Stmt::child_iterator ObjCIvarRefExpr::child_begin() { return &Base; }
+Stmt::child_iterator ObjCIvarRefExpr::child_end() { return &Base+1; }
// ObjCPropertyRefExpr
-Stmt::child_iterator ObjCPropertyRefExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Base);
-}
-
-Stmt::child_iterator ObjCPropertyRefExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Base)+1;
-}
+Stmt::child_iterator ObjCPropertyRefExpr::child_begin() { return &Base; }
+Stmt::child_iterator ObjCPropertyRefExpr::child_end() { return &Base+1; }
// ObjCSuperRefExpr
Stmt::child_iterator ObjCSuperRefExpr::child_begin() { return child_iterator();}
@@ -1234,32 +1224,20 @@
Stmt::child_iterator FloatingLiteral::child_end() { return child_iterator(); }
// ImaginaryLiteral
-Stmt::child_iterator ImaginaryLiteral::child_begin() {
- return reinterpret_cast<Stmt**>(&Val);
-}
-Stmt::child_iterator ImaginaryLiteral::child_end() {
- return reinterpret_cast<Stmt**>(&Val)+1;
-}
+Stmt::child_iterator ImaginaryLiteral::child_begin() { return &Val; }
+Stmt::child_iterator ImaginaryLiteral::child_end() { return &Val+1; }
// StringLiteral
Stmt::child_iterator StringLiteral::child_begin() { return child_iterator(); }
Stmt::child_iterator StringLiteral::child_end() { return child_iterator(); }
// ParenExpr
-Stmt::child_iterator ParenExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Val);
-}
-Stmt::child_iterator ParenExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Val)+1;
-}
+Stmt::child_iterator ParenExpr::child_begin() { return &Val; }
+Stmt::child_iterator ParenExpr::child_end() { return &Val+1; }
// UnaryOperator
-Stmt::child_iterator UnaryOperator::child_begin() {
- return reinterpret_cast<Stmt**>(&Val);
-}
-Stmt::child_iterator UnaryOperator::child_end() {
- return reinterpret_cast<Stmt**>(&Val+1);
-}
+Stmt::child_iterator UnaryOperator::child_begin() { return &Val; }
+Stmt::child_iterator UnaryOperator::child_end() { return &Val+1; }
// SizeOfAlignOfTypeExpr
Stmt::child_iterator SizeOfAlignOfTypeExpr::child_begin() {
@@ -1276,74 +1254,54 @@
// ArraySubscriptExpr
Stmt::child_iterator ArraySubscriptExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs);
+ return &SubExprs[0];
}
Stmt::child_iterator ArraySubscriptExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
+ return &SubExprs[0]+END_EXPR;
}
// CallExpr
Stmt::child_iterator CallExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs[0]);
+ return &SubExprs[0];
}
Stmt::child_iterator CallExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs[NumArgs+ARGS_START]);
+ return &SubExprs[0]+NumArgs+ARGS_START;
}
// MemberExpr
-Stmt::child_iterator MemberExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Base);
-}
-Stmt::child_iterator MemberExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Base)+1;
-}
+Stmt::child_iterator MemberExpr::child_begin() { return &Base; }
+Stmt::child_iterator MemberExpr::child_end() { return &Base+1; }
// ExtVectorElementExpr
-Stmt::child_iterator ExtVectorElementExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Base);
-}
-Stmt::child_iterator ExtVectorElementExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Base)+1;
-}
+Stmt::child_iterator ExtVectorElementExpr::child_begin() { return &Base; }
+Stmt::child_iterator ExtVectorElementExpr::child_end() { return &Base+1; }
// CompoundLiteralExpr
-Stmt::child_iterator CompoundLiteralExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Init);
-}
-Stmt::child_iterator CompoundLiteralExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Init)+1;
-}
+Stmt::child_iterator CompoundLiteralExpr::child_begin() { return &Init; }
+Stmt::child_iterator CompoundLiteralExpr::child_end() { return &Init+1; }
// ImplicitCastExpr
-Stmt::child_iterator ImplicitCastExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Op);
-}
-Stmt::child_iterator ImplicitCastExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Op)+1;
-}
+Stmt::child_iterator ImplicitCastExpr::child_begin() { return &Op; }
+Stmt::child_iterator ImplicitCastExpr::child_end() { return &Op+1; }
// CastExpr
-Stmt::child_iterator CastExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Op);
-}
-Stmt::child_iterator CastExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Op)+1;
-}
+Stmt::child_iterator CastExpr::child_begin() { return &Op; }
+Stmt::child_iterator CastExpr::child_end() { return &Op+1; }
// BinaryOperator
Stmt::child_iterator BinaryOperator::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs);
+ return &SubExprs[0];
}
Stmt::child_iterator BinaryOperator::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
+ return &SubExprs[0]+END_EXPR;
}
// ConditionalOperator
Stmt::child_iterator ConditionalOperator::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs);
+ return &SubExprs[0];
}
Stmt::child_iterator ConditionalOperator::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
+ return &SubExprs[0]+END_EXPR;
}
// AddrLabelExpr
@@ -1351,12 +1309,8 @@
Stmt::child_iterator AddrLabelExpr::child_end() { return child_iterator(); }
// StmtExpr
-Stmt::child_iterator StmtExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubStmt);
-}
-Stmt::child_iterator StmtExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubStmt)+1;
-}
+Stmt::child_iterator StmtExpr::child_begin() { return &SubStmt; }
+Stmt::child_iterator StmtExpr::child_end() { return &SubStmt+1; }
// TypesCompatibleExpr
Stmt::child_iterator TypesCompatibleExpr::child_begin() {
@@ -1368,47 +1322,31 @@
}
// ChooseExpr
-Stmt::child_iterator ChooseExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs);
-}
-
-Stmt::child_iterator ChooseExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs)+END_EXPR;
-}
+Stmt::child_iterator ChooseExpr::child_begin() { return &SubExprs[0]; }
+Stmt::child_iterator ChooseExpr::child_end() { return &SubExprs[0]+END_EXPR; }
// OverloadExpr
-Stmt::child_iterator OverloadExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs[0]);
-}
-Stmt::child_iterator OverloadExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs[NumExprs]);
-}
+Stmt::child_iterator OverloadExpr::child_begin() { return &SubExprs[0]; }
+Stmt::child_iterator OverloadExpr::child_end() { return &SubExprs[0]+NumExprs; }
// ShuffleVectorExpr
Stmt::child_iterator ShuffleVectorExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs[0]);
+ return &SubExprs[0];
}
Stmt::child_iterator ShuffleVectorExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs[NumExprs]);
+ return &SubExprs[0]+NumExprs;
}
// VAArgExpr
-Stmt::child_iterator VAArgExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&Val);
-}
-
-Stmt::child_iterator VAArgExpr::child_end() {
- return reinterpret_cast<Stmt**>(&Val)+1;
-}
+Stmt::child_iterator VAArgExpr::child_begin() { return &Val; }
+Stmt::child_iterator VAArgExpr::child_end() { return &Val+1; }
// InitListExpr
Stmt::child_iterator InitListExpr::child_begin() {
- return reinterpret_cast<Stmt**>(InitExprs.size() ?
- &InitExprs[0] : 0);
+ return InitExprs.size() ? &InitExprs[0] : 0;
}
Stmt::child_iterator InitListExpr::child_end() {
- return reinterpret_cast<Stmt**>(InitExprs.size() ?
- &InitExprs[0] + InitExprs.size() : 0);
+ return InitExprs.size() ? &InitExprs[0] + InitExprs.size() : 0;
}
// ObjCStringLiteral
@@ -1441,9 +1379,9 @@
// ObjCMessageExpr
Stmt::child_iterator ObjCMessageExpr::child_begin() {
- return reinterpret_cast<Stmt**>(&SubExprs[ getReceiver() ? 0 : ARGS_START ]);
+ return getReceiver() ? &SubExprs[0] : &SubExprs[0] + ARGS_START;
}
Stmt::child_iterator ObjCMessageExpr::child_end() {
- return reinterpret_cast<Stmt**>(&SubExprs[getNumArgs()+ARGS_START]);
+ return &SubExprs[0]+ARGS_START+getNumArgs();
}
diff --git a/lib/AST/StmtSerialization.cpp b/lib/AST/StmtSerialization.cpp
index 6fcc1ef..cc794f0 100644
--- a/lib/AST/StmtSerialization.cpp
+++ b/lib/AST/StmtSerialization.cpp
@@ -338,7 +338,7 @@
QualType t = QualType::ReadVal(D);
SourceLocation L = SourceLocation::ReadVal(D);
unsigned NumArgs = D.ReadInt();
- Expr** SubExprs = new Expr*[NumArgs+1];
+ Stmt** SubExprs = new Stmt*[NumArgs+1];
D.BatchReadOwnedPtrs(NumArgs+1, SubExprs, C);
return new CallExpr(SubExprs,NumArgs,t,L);