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translate-c: support pointer casting

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also avoid some unnecessary casts
This commit is contained in:
Andrew Kelley 2017-11-26 20:05:55 -05:00
parent 93fac5f257
commit 671183fa9a
2 changed files with 97 additions and 54 deletions
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118
src/translate_c.cpp
View File

@ -440,6 +440,10 @@ static AstNode *trans_create_node_apint(Context *c, const llvm::APSInt &aps_int)
}
static const Type *qual_type_canon(QualType qt) {
return qt.getCanonicalType().getTypePtr();
}
static QualType get_expr_qual_type(Context *c, const Expr *expr) {
// String literals in C are `char *` but they should really be `const char *`.
if (expr->getStmtClass() == Stmt::ImplicitCastExprClass) {
@ -462,10 +466,7 @@ static AstNode *get_expr_type(Context *c, const Expr *expr) {
return trans_qual_type(c, get_expr_qual_type(c, expr), expr->getLocStart());
}
static bool expr_types_equal(Context *c, const Expr *expr1, const Expr *expr2) {
QualType t1 = get_expr_qual_type(c, expr1);
QualType t2 = get_expr_qual_type(c, expr2);
static bool qual_types_equal(QualType t1, QualType t2) {
if (t1.isConstQualified() != t2.isConstQualified()) {
return false;
}
@ -482,26 +483,27 @@ static bool is_c_void_type(AstNode *node) {
return (node->type == NodeTypeSymbol && buf_eql_str(node->data.symbol_expr.symbol, "c_void"));
}
static AstNode* trans_c_cast(Context *c, const SourceLocation &source_location, const QualType &qt, AstNode *expr) {
// TODO: maybe widen to increase size
// TODO: maybe bitcast to change sign
// TODO: maybe truncate to reduce size
return trans_create_node_fn_call_1(c, trans_qual_type(c, qt, source_location), expr);
static bool expr_types_equal(Context *c, const Expr *expr1, const Expr *expr2) {
QualType t1 = get_expr_qual_type(c, expr1);
QualType t2 = get_expr_qual_type(c, expr2);
return qual_types_equal(t1, t2);
}
static bool qual_type_is_fn_ptr(Context *c, const QualType &qt) {
const Type *ty = qt.getTypePtr();
static bool qual_type_is_ptr(QualType qt) {
const Type *ty = qual_type_canon(qt);
return ty->getTypeClass() == Type::Pointer;
}
static bool qual_type_is_fn_ptr(Context *c, QualType qt) {
const Type *ty = qual_type_canon(qt);
if (ty->getTypeClass() != Type::Pointer) {
return false;
}
const PointerType *pointer_ty = static_cast<const PointerType*>(ty);
QualType child_qt = pointer_ty->getPointeeType();
const Type *child_ty = child_qt.getTypePtr();
if (child_ty->getTypeClass() != Type::Paren) {
return false;
}
const ParenType *paren_ty = static_cast<const ParenType *>(child_ty);
return paren_ty->getInnerType().getTypePtr()->getTypeClass() == Type::FunctionProto;
return child_ty->getTypeClass() == Type::FunctionProto;
}
static uint32_t qual_type_int_bit_width(Context *c, const QualType &qt, const SourceLocation &source_loc) {
@ -594,17 +596,26 @@ static bool qual_type_child_is_fn_proto(const QualType &qt) {
return false;
}
static QualType resolve_any_typedef(Context *c, QualType qt) {
const Type * ty = qt.getTypePtr();
if (ty->getTypeClass() != Type::Typedef)
return qt;
const TypedefType *typedef_ty = static_cast<const TypedefType*>(ty);
const TypedefNameDecl *typedef_decl = typedef_ty->getDecl();
return typedef_decl->getUnderlyingType();
static AstNode* trans_c_cast(Context *c, const SourceLocation &source_location, QualType dest_type,
QualType src_type, AstNode *expr)
{
if (qual_types_equal(dest_type, src_type)) {
return expr;
}
if (qual_type_is_ptr(dest_type) && qual_type_is_ptr(src_type)) {
AstNode *ptr_cast_node = trans_create_node_builtin_fn_call_str(c, "ptrCast");
ptr_cast_node->data.fn_call_expr.params.append(trans_qual_type(c, dest_type, source_location));
ptr_cast_node->data.fn_call_expr.params.append(expr);
return ptr_cast_node;
}
// TODO: maybe widen to increase size
// TODO: maybe bitcast to change sign
// TODO: maybe truncate to reduce size
return trans_create_node_fn_call_1(c, trans_qual_type(c, dest_type, source_location), expr);
}
static bool c_is_signed_integer(Context *c, QualType qt) {
const Type *c_type = resolve_any_typedef(c, qt).getTypePtr();
const Type *c_type = qual_type_canon(qt);
if (c_type->getTypeClass() != Type::Builtin)
return false;
const BuiltinType *builtin_ty = static_cast<const BuiltinType*>(c_type);
@ -623,7 +634,7 @@ static bool c_is_signed_integer(Context *c, QualType qt) {
}
static bool c_is_unsigned_integer(Context *c, QualType qt) {
const Type *c_type = resolve_any_typedef(c, qt).getTypePtr();
const Type *c_type = qual_type_canon(qt);
if (c_type->getTypeClass() != Type::Builtin)
return false;
const BuiltinType *builtin_ty = static_cast<const BuiltinType*>(c_type);
@ -891,6 +902,11 @@ static AstNode *trans_type(Context *c, const Type *ty, const SourceLocation &sou
return nullptr;
}
// convert c_void to actual void (only for return type)
// we do want to look at the AstNode instead of QualType, because
// if they do something like:
// typedef Foo void;
// void foo(void) -> Foo;
// we want to keep the return type AST node.
if (is_c_void_type(proto_node->data.fn_proto.return_type)) {
proto_node->data.fn_proto.return_type = nullptr;
}
@ -1317,19 +1333,28 @@ static AstNode *trans_create_compound_assign_shift(Context *c, ResultUsed result
if (rhs == nullptr) return nullptr;
AstNode *coerced_rhs = trans_create_node_fn_call_1(c, rhs_type, rhs);
// operation_type(*_ref)
AstNode *operation_type_cast = trans_c_cast(c, rhs_location,
stmt->getComputationLHSType(),
stmt->getLHS()->getType(),
trans_create_node_prefix_op(c, PrefixOpDereference,
trans_create_node_symbol(c, tmp_var_name)));
// result_type(... >> u5(rhs))
AstNode *result_type_cast = trans_c_cast(c, rhs_location,
stmt->getComputationResultType(),
stmt->getComputationLHSType(),
trans_create_node_bin_op(c,
operation_type_cast,
bin_op,
coerced_rhs));
// *_ref = ...
AstNode *assign_statement = trans_create_node_bin_op(c,
trans_create_node_prefix_op(c, PrefixOpDereference,
trans_create_node_symbol(c, tmp_var_name)),
BinOpTypeAssign,
trans_c_cast(c, rhs_location,
stmt->getComputationResultType(),
trans_create_node_bin_op(c,
trans_c_cast(c, rhs_location,
stmt->getComputationLHSType(),
trans_create_node_prefix_op(c, PrefixOpDereference,
trans_create_node_symbol(c, tmp_var_name))),
bin_op,
coerced_rhs)));
BinOpTypeAssign, result_type_cast);
child_scope->node->data.block.statements.append(assign_statement);
if (result_used == ResultUsedYes) {
@ -1474,7 +1499,8 @@ static AstNode *trans_implicit_cast_expr(Context *c, TransScope *scope, const Im
AstNode *target_node = trans_expr(c, ResultUsedYes, scope, stmt->getSubExpr(), TransRValue);
if (target_node == nullptr)
return nullptr;
return trans_c_cast(c, stmt->getExprLoc(), stmt->getType(), target_node);
return trans_c_cast(c, stmt->getExprLoc(), stmt->getType(),
stmt->getSubExpr()->getType(), target_node);
}
case CK_FunctionToPointerDecay:
case CK_ArrayToPointerDecay:
@ -2177,9 +2203,23 @@ static AstNode *trans_call_expr(Context *c, ResultUsed result_used, TransScope *
if (callee_raw_node == nullptr)
return nullptr;
AstNode *callee_node;
AstNode *callee_node = nullptr;
if (qual_type_is_fn_ptr(c, stmt->getCallee()->getType())) {
callee_node = trans_create_node_prefix_op(c, PrefixOpUnwrapMaybe, callee_raw_node);
if (stmt->getCallee()->getStmtClass() == Stmt::ImplicitCastExprClass) {
const ImplicitCastExpr *implicit_cast = static_cast<const ImplicitCastExpr *>(stmt->getCallee());
if (implicit_cast->getCastKind() == CK_FunctionToPointerDecay) {
if (implicit_cast->getSubExpr()->getStmtClass() == Stmt::DeclRefExprClass) {
const DeclRefExpr *decl_ref = static_cast<const DeclRefExpr *>(implicit_cast->getSubExpr());
const Decl *decl = decl_ref->getFoundDecl();
if (decl->getKind() == Decl::Function) {
callee_node = callee_raw_node;
}
}
}
}
if (callee_node == nullptr) {
callee_node = trans_create_node_prefix_op(c, PrefixOpUnwrapMaybe, callee_raw_node);
}
} else {
callee_node = callee_raw_node;
}
@ -2237,7 +2277,7 @@ static AstNode *trans_c_style_cast_expr(Context *c, ResultUsed result_used, Tran
if (sub_expr_node == nullptr)
return nullptr;
return trans_c_cast(c, stmt->getLocStart(), stmt->getType(), sub_expr_node);
return trans_c_cast(c, stmt->getLocStart(), stmt->getType(), stmt->getSubExpr()->getType(), sub_expr_node);
}
static AstNode *trans_unary_expr_or_type_trait_expr(Context *c, TransScope *scope,

33
test/translate_c.zig
View File

@ -677,12 +677,12 @@ pub fn addCases(cases: &tests.TranslateCContext) {
\\ };
\\ a >>= @import("std").math.Log2Int(c_int)({
\\ const _ref = &a;
\\ (*_ref) = c_int(c_int(*_ref) >> @import("std").math.Log2Int(c_int)(1));
\\ (*_ref) = ((*_ref) >> @import("std").math.Log2Int(c_int)(1));
\\ *_ref
\\ });
\\ a <<= @import("std").math.Log2Int(c_int)({
\\ const _ref = &a;
\\ (*_ref) = c_int(c_int(*_ref) << @import("std").math.Log2Int(c_int)(1));
\\ (*_ref) = ((*_ref) << @import("std").math.Log2Int(c_int)(1));
\\ *_ref
\\ });
\\}
@ -735,12 +735,12 @@ pub fn addCases(cases: &tests.TranslateCContext) {
\\ };
\\ a >>= @import("std").math.Log2Int(c_uint)({
\\ const _ref = &a;
\\ (*_ref) = c_uint(c_uint(*_ref) >> @import("std").math.Log2Int(c_uint)(1));
\\ (*_ref) = ((*_ref) >> @import("std").math.Log2Int(c_uint)(1));
\\ *_ref
\\ });
\\ a <<= @import("std").math.Log2Int(c_uint)({
\\ const _ref = &a;
\\ (*_ref) = c_uint(c_uint(*_ref) << @import("std").math.Log2Int(c_uint)(1));
\\ (*_ref) = ((*_ref) << @import("std").math.Log2Int(c_uint)(1));
\\ *_ref
\\ });
\\}
@ -878,17 +878,21 @@ pub fn addCases(cases: &tests.TranslateCContext) {
cases.addC("deref function pointer",
\\void foo(void) {}
\\void baz(void) {}
\\void bar(void) {
\\ void(*f)(void) = foo;
\\ f();
\\ (*(f))();
\\ baz();
\\}
,
\\export fn foo() {}
\\export fn baz() {}
\\export fn bar() {
\\ var f: ?extern fn() = foo;
\\ (??f)();
\\ (??f)();
\\ baz();
\\}
);
@ -1100,15 +1104,14 @@ pub fn addCases(cases: &tests.TranslateCContext) {
\\ return x;
\\}
);
cases.add("pointer casting",
\\float *ptrcast(int *a) {
\\ return (float *)a;
\\}
,
\\fn ptrcast(a: ?&c_int) -> ?&f32 {
\\ return @ptrCast(?&f32, a);
\\}
);
}
// TODO
//float *ptrcast(int *a) {
// return (float *)a;
//}
// should translate to
// fn ptrcast(a: ?&c_int) -> ?&f32 {
// return @ptrCast(?&f32, a);
// }