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translate-c: better way to translate switch

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previously `continue` would be handled incorrectly
This commit is contained in:
Andrew Kelley 2017-11-26 15:58:49 -05:00
parent 1b0e90f70b
commit aa2ca3f02c
2 changed files with 42 additions and 25 deletions
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60
src/translate_c.cpp
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@ -82,6 +82,7 @@ struct TransScopeSwitch {
AstNode *switch_node;
uint32_t case_index;
bool found_default;
Buf *end_label_name;
};
struct TransScopeVar {
@ -248,6 +249,18 @@ static AstNode *trans_create_node_addr_of(Context *c, bool is_const, bool is_vol
return node;
}
static AstNode *trans_create_node_goto(Context *c, Buf *label_name) {
AstNode *goto_node = trans_create_node(c, NodeTypeGoto);
goto_node->data.goto_expr.name = label_name;
return goto_node;
}
static AstNode *trans_create_node_label(Context *c, Buf *label_name) {
AstNode *label_node = trans_create_node(c, NodeTypeLabel);
label_node->data.label.name = label_name;
return label_node;
}
static AstNode *trans_create_node_bool(Context *c, bool value) {
AstNode *bool_node = trans_create_node(c, NodeTypeBoolLiteral);
bool_node->data.bool_literal.value = value;
@ -2283,11 +2296,7 @@ static AstNode *trans_do_loop(Context *c, TransScope *parent_scope, const DoStmt
}
static AstNode *trans_switch_stmt(Context *c, TransScope *parent_scope, const SwitchStmt *stmt) {
TransScopeWhile *while_scope = trans_scope_while_create(c, parent_scope);
while_scope->node->data.while_expr.condition = trans_create_node_bool(c, true);
TransScopeBlock *block_scope = trans_scope_block_create(c, &while_scope->base);
while_scope->node->data.while_expr.body = block_scope->node;
TransScopeBlock *block_scope = trans_scope_block_create(c, parent_scope);
TransScopeSwitch *switch_scope;
@ -2305,6 +2314,10 @@ static AstNode *trans_switch_stmt(Context *c, TransScope *parent_scope, const Sw
}
block_scope->node->data.block.statements.append(switch_scope->switch_node);
// TODO avoid name collisions
Buf *end_label_name = buf_create_from_str("end");
switch_scope->end_label_name = end_label_name;
const Expr *cond_expr = stmt->getCond();
assert(cond_expr != nullptr);
@ -2336,9 +2349,11 @@ static AstNode *trans_switch_stmt(Context *c, TransScope *parent_scope, const Sw
}
// This is necessary if the last switch case "falls through" the end of the switch block
block_scope->node->data.block.statements.append(trans_create_node(c, NodeTypeBreak));
block_scope->node->data.block.statements.append(trans_create_node_goto(c, end_label_name));
return while_scope->node;
block_scope->node->data.block.statements.append(trans_create_node_label(c, end_label_name));
return block_scope->node;
}
static int trans_switch_case(Context *c, TransScope *parent_scope, const CaseStmt *stmt, AstNode **out_node,
@ -2365,18 +2380,13 @@ static int trans_switch_case(Context *c, TransScope *parent_scope, const CaseStm
return ErrorUnexpected;
prong_node->data.switch_prong.items.append(item_node);
AstNode *goto_node = trans_create_node(c, NodeTypeGoto);
goto_node->data.goto_expr.name = label_name;
prong_node->data.switch_prong.expr = goto_node;
prong_node->data.switch_prong.expr = trans_create_node_goto(c, label_name);
switch_scope->switch_node->data.switch_expr.prongs.append(prong_node);
}
AstNode *label_node = trans_create_node(c, NodeTypeLabel);
label_node->data.label.name = label_name;
TransScopeBlock *scope_block = trans_scope_block_find(parent_scope);
scope_block->node->data.block.statements.append(label_node);
scope_block->node->data.block.statements.append(trans_create_node_label(c, label_name));
AstNode *sub_stmt_node;
TransScope *new_scope = trans_stmt(c, parent_scope, stmt->getSubStmt(), &sub_stmt_node);
@ -2399,23 +2409,19 @@ static int trans_switch_default(Context *c, TransScope *parent_scope, const Defa
Buf *label_name = buf_sprintf("default");
AstNode *label_node = trans_create_node(c, NodeTypeLabel);
label_node->data.label.name = label_name;
{
// Add the prong
AstNode *prong_node = trans_create_node(c, NodeTypeSwitchProng);
AstNode *goto_node = trans_create_node(c, NodeTypeGoto);
goto_node->data.goto_expr.name = label_name;
prong_node->data.switch_prong.expr = goto_node;
prong_node->data.switch_prong.expr = trans_create_node_goto(c, label_name);
switch_scope->switch_node->data.switch_expr.prongs.append(prong_node);
switch_scope->found_default = true;
}
TransScopeBlock *scope_block = trans_scope_block_find(parent_scope);
scope_block->node->data.block.statements.append(label_node);
scope_block->node->data.block.statements.append(trans_create_node_label(c, label_name));
AstNode *sub_stmt_node;
TransScope *new_scope = trans_stmt(c, parent_scope, stmt->getSubStmt(), &sub_stmt_node);
@ -2500,7 +2506,17 @@ static AstNode *trans_string_literal(Context *c, TransScope *scope, const String
}
static AstNode *trans_break_stmt(Context *c, TransScope *scope, const BreakStmt *stmt) {
return trans_create_node(c, NodeTypeBreak);
TransScope *cur_scope = scope;
while (cur_scope != nullptr) {
if (cur_scope->id == TransScopeIdWhile) {
return trans_create_node(c, NodeTypeBreak);
} else if (cur_scope->id == TransScopeIdSwitch) {
TransScopeSwitch *switch_scope = (TransScopeSwitch *)cur_scope;
return trans_create_node_goto(c, switch_scope->end_label_name);
}
cur_scope = cur_scope->parent;
}
zig_unreachable();
}
static AstNode *trans_continue_stmt(Context *c, TransScope *scope, const ContinueStmt *stmt) {

7
test/translate_c.zig
View File

@ -1019,7 +1019,7 @@ pub fn addCases(cases: &tests.TranslateCContext) {
,
\\fn foo(_arg_x: c_int) -> c_int {
\\ var x = _arg_x;
\\ while (true) {
\\ {
\\ switch (x) {
\\ 1 => goto case_0,
\\ 2 => goto case_1,
@ -1030,13 +1030,14 @@ pub fn addCases(cases: &tests.TranslateCContext) {
\\ case_0:
\\ x += 1;
\\ case_1:
\\ break;
\\ goto end;
\\ case_2:
\\ case_3:
\\ return x + 1;
\\ default:
\\ return 10;
\\ break;
\\ goto end;
\\ end:
\\ };
\\ return x + 13;
\\}