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base repository: ziglang/zig
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head repository: ziglang/zig
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compare: 9a8545d5903f
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  • 2 commits
  • 2 files changed
  • 1 contributor

Commits on Nov 26, 2017

  1. translate-c: better way to translate switch 

    previously `continue` would be handled incorrectly
    @andrewrk
    andrewrk committed Nov 26, 2017
    Copy the full SHA
    aa2ca3f View commit details

  2. translate-c: fix translation when no default switch case

    @andrewrk
    andrewrk committed Nov 26, 2017
    Copy the full SHA
    9a8545d View commit details
Showing with 81 additions and 26 deletions.
  1. +39 −23 src/translate_c.cpp
  2. +42 −3 test/translate_c.zig
62 changes: 39 additions & 23 deletions src/translate_c.cpp
View file
Original file line number Diff line number Diff line change
@@ -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);

@@ -2331,14 +2344,16 @@ static AstNode *trans_switch_stmt(Context *c, TransScope *parent_scope, const Sw

if (!switch_scope->found_default && !stmt->isAllEnumCasesCovered()) {
AstNode *prong_node = trans_create_node(c, NodeTypeSwitchProng);
prong_node->data.switch_prong.expr = trans_create_node(c, NodeTypeBreak);
prong_node->data.switch_prong.expr = trans_create_node_goto(c, end_label_name);
switch_scope->switch_node->data.switch_expr.prongs.append(prong_node);
}

// 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) {
45 changes: 42 additions & 3 deletions test/translate_c.zig
View file
Original file line number Diff line number Diff line change
@@ -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 +1030,52 @@ 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;
\\}
);

cases.add("switch statement with no default",
\\int foo(int x) {
\\ switch (x) {
\\ case 1:
\\ x += 1;
\\ case 2:
\\ break;
\\ case 3:
\\ case 4:
\\ return x + 1;
\\ }
\\ return x + 13;
\\}
,
\\fn foo(_arg_x: c_int) -> c_int {
\\ var x = _arg_x;
\\ {
\\ switch (x) {
\\ 1 => goto case_0,
\\ 2 => goto case_1,
\\ 3 => goto case_2,
\\ 4 => goto case_3,
\\ else => goto end,
\\ };
\\ case_0:
\\ x += 1;
\\ case_1:
\\ goto end;
\\ case_2:
\\ case_3:
\\ return x + 1;
\\ goto end;
\\ end:
\\ };
\\ return x + 13;
\\}