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translate-c: convert most control flow

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This commit is contained in:
Veikka Tuominen 2021-02-10 22:30:19 +02:00
parent d8b9fca0b1
commit 66dd64ec15
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GPG Key ID: 59AEB8936E16A6AC
2 changed files with 56 additions and 74 deletions
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123
src/translate_c.zig
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@ -107,6 +107,7 @@ const Scope = struct {
// do while, we want to put `if (cond) break;` at the end.
const alloc_len = self.statements.items.len + @boolToInt(self.base.parent.?.id == .Loop);
const stmts = try c.arena.alloc(Node, alloc_len);
stmts.len -= 1;
mem.copy(Node, stmts, self.statements.items);
return Node.block.create(c.arena, .{
.lable = self.label,
@ -1748,7 +1749,7 @@ fn transCCast(
if (dst_type.eq(src_type)) return expr;
if (qualTypeIsPtr(dst_type) and qualTypeIsPtr(src_type))
return transCPtrCast(c, loc, dst_type, src_type, expr);
const dst_node = try transQualType(c, dst_type, loc);
if (cIsInteger(dst_type) and (cIsInteger(src_type) or cIsEnum(src_type))) {
// 1. If src_type is an enum, determine the underlying signed int type
@ -1931,7 +1932,7 @@ fn transInitListExprArray(
if (all_count == 0) {
return Node.empty_array.create(c.arena, try transQualType(c, child_qt, source_loc));
}
const ty_node = try transType(ty);
const init_node = if (init_count != 0) blk: {
const init_list = try c.arena.alloc(Node, init_count);
@ -2058,14 +2059,12 @@ fn transImplicitValueInitExpr(
}
fn transIfStmt(
rp: RestorePoint,
c: *Context,
scope: *Scope,
stmt: *const clang.IfStmt,
) TransError!*ast.Node {
) TransError!Node {
// if (c) t
// if (c) t else e
const if_node = try transCreateNodeIf(rp.c);
var cond_scope = Scope.Condition{
.base = .{
.parent = scope,
@ -2074,26 +2073,21 @@ fn transIfStmt(
};
defer cond_scope.deinit();
const cond_expr = @ptrCast(*const clang.Expr, stmt.getCond());
if_node.condition = try transBoolExpr(rp, &cond_scope.base, cond_expr, .used, .r_value, false);
_ = try appendToken(rp.c, .RParen, ")");
const cond = try transBoolExpr(c, &cond_scope.base, cond_expr, .used, .r_value);
if_node.body = try transStmt(rp, scope, stmt.getThen(), .unused, .r_value);
if (stmt.getElse()) |expr| {
if_node.@"else" = try transCreateNodeElse(rp.c);
if_node.@"else".?.body = try transStmt(rp, scope, expr, .unused, .r_value);
}
_ = try appendToken(rp.c, .Semicolon, ";");
return &if_node.base;
const then_body = try transStmt(c, scope, stmt.getThen(), .unused, .r_value);
const else_body = if (stmt.getElse()) |expr|
try transStmt(c, scope, expr, .unused, .r_value)
else
null;
return Node.@"if".create(c.arena, .{ .cond = cond, .then = then_body, .@"else" = else_body });
}
fn transWhileLoop(
rp: RestorePoint,
c: *Context,
scope: *Scope,
stmt: *const clang.WhileStmt,
) TransError!*ast.Node {
const while_node = try transCreateNodeWhile(rp.c);
) TransError!Node {
var cond_scope = Scope.Condition{
.base = .{
.parent = scope,
@ -2102,35 +2096,28 @@ fn transWhileLoop(
};
defer cond_scope.deinit();
const cond_expr = @ptrCast(*const clang.Expr, stmt.getCond());
while_node.condition = try transBoolExpr(rp, &cond_scope.base, cond_expr, .used, .r_value, false);
_ = try appendToken(rp.c, .RParen, ")");
const cond = try transBoolExpr(c, &cond_scope.base, cond_expr, .used, .r_value);
var loop_scope = Scope{
.parent = scope,
.id = .Loop,
};
while_node.body = try transStmt(rp, &loop_scope, stmt.getBody(), .unused, .r_value);
_ = try appendToken(rp.c, .Semicolon, ";");
return &while_node.base;
const body = try transStmt(c, &loop_scope, stmt.getBody(), .unused, .r_value);
return Node.@"while".create(c.arena, .{ .cond = cond, .body = body, .cont_expr = null });
}
fn transDoWhileLoop(
rp: RestorePoint,
c: *Context,
scope: *Scope,
stmt: *const clang.DoStmt,
) TransError!*ast.Node {
const while_node = try transCreateNodeWhile(rp.c);
while_node.condition = try transCreateNodeBoolLiteral(rp.c, true);
_ = try appendToken(rp.c, .RParen, ")");
var new = false;
) TransError!Node {
var loop_scope = Scope{
.parent = scope,
.id = .Loop,
};
// if (!cond) break;
const if_node = try transCreateNodeIf(rp.c);
const if_node = try transCreateNodeIf(c);
var cond_scope = Scope.Condition{
.base = .{
.parent = scope,
@ -2138,12 +2125,8 @@ fn transDoWhileLoop(
},
};
defer cond_scope.deinit();
const prefix_op = try transCreateNodeSimplePrefixOp(rp.c, .BoolNot, .Bang, "!");
prefix_op.rhs = try transBoolExpr(rp, &cond_scope.base, @ptrCast(*const clang.Expr, stmt.getCond()), .used, .r_value, true);
_ = try appendToken(rp.c, .RParen, ")");
if_node.condition = &prefix_op.base;
if_node.body = &(try transCreateNodeBreak(rp.c, null, null)).base;
_ = try appendToken(rp.c, .Semicolon, ";");
const cond = try transBoolExpr(c, &cond_scope.base, @ptrCast(*const clang.Expr, stmt.getCond()), .used, .r_value);
const if_not_break = try Node.if_not_break.create(c.arena, cond);
const body_node = if (stmt.getBody().getStmtClass() == .CompoundStmtClass) blk: {
// there's already a block in C, so we'll append our condition to it.
@ -2156,8 +2139,12 @@ fn transDoWhileLoop(
// zig: b;
// zig: if (!cond) break;
// zig: }
const node = try transStmt(rp, &loop_scope, stmt.getBody(), .unused, .r_value);
break :blk node.castTag(.Block).?;
const node = try transStmt(c, &loop_scope, stmt.getBody(), .unused, .r_value);
const block = node.castTag(.block);
block.data.stmts.len += 1; // This is safe since we reserve one extra space in Scope.Block.complete.
block.data.stmts[block.data.stmts.len - 1] = if_not_break;
break :blk node;
} else blk: {
// the C statement is without a block, so we need to create a block to contain it.
// c: do
@ -2167,27 +2154,19 @@ fn transDoWhileLoop(
// zig: a;
// zig: if (!cond) break;
// zig: }
new = true;
const block = try rp.c.createBlock(2);
block.statements_len = 1; // over-allocated so we can add another below
block.statements()[0] = try transStmt(rp, &loop_scope, stmt.getBody(), .unused, .r_value);
break :blk block;
const statements = try c.arena.create(Node, 2);
statements[0] = try transStmt(c, &loop_scope, stmt.getBody(), .unused, .r_value);
statements[1] = if_not_break;
break :blk try Node.block.create(c.arena, .{ .label = null, .stmts = statements });
};
// In both cases above, we reserved 1 extra statement.
body_node.statements_len += 1;
body_node.statements()[body_node.statements_len - 1] = &if_node.base;
if (new)
body_node.rbrace = try appendToken(rp.c, .RBrace, "}");
while_node.body = &body_node.base;
return &while_node.base;
return Node.while_true.create(c.arena, body_node);
}
fn transForLoop(
rp: RestorePoint,
c: *Context,
scope: *Scope,
stmt: *const clang.ForStmt,
) TransError!*ast.Node {
) TransError!Node {
var loop_scope = Scope{
.parent = scope,
.id = .Loop,
@ -2197,9 +2176,9 @@ fn transForLoop(
defer if (block_scope) |*bs| bs.deinit();
if (stmt.getInit()) |init| {
block_scope = try Scope.Block.init(rp.c, scope, false);
block_scope = try Scope.Block.init(c, scope, false);
loop_scope.parent = &block_scope.?.base;
const init_node = try transStmt(rp, &block_scope.?.base, init, .unused, .r_value);
const init_node = try transStmt(c, &block_scope.?.base, init, .unused, .r_value);
try block_scope.?.statements.append(init_node);
}
var cond_scope = Scope.Condition{
@ -2210,27 +2189,23 @@ fn transForLoop(
};
defer cond_scope.deinit();
const while_node = try transCreateNodeWhile(rp.c);
while_node.condition = if (stmt.getCond()) |cond|
try transBoolExpr(rp, &cond_scope.base, cond, .used, .r_value, false)
const cond = if (stmt.getCond()) |cond|
try transBoolExpr(c, &cond_scope.base, cond, .used, .r_value)
else
try transCreateNodeBoolLiteral(rp.c, true);
_ = try appendToken(rp.c, .RParen, ")");
Node.true_literal.init();
if (stmt.getInc()) |incr| {
_ = try appendToken(rp.c, .Colon, ":");
_ = try appendToken(rp.c, .LParen, "(");
while_node.continue_expr = try transExpr(rp, &cond_scope.base, incr, .unused, .r_value);
_ = try appendToken(rp.c, .RParen, ")");
}
const cont_expr = if (stmt.getInc()) |incr|
try transExpr(c, &cond_scope.base, incr, .unused, .r_value)
else
null;
while_node.body = try transStmt(rp, &loop_scope, stmt.getBody(), .unused, .r_value);
const body = try transStmt(c, &loop_scope, stmt.getBody(), .unused, .r_value);
const while_node = try Node.@"while".create(c.arena, .{ .cond = cond, .body = body, .cont_expr = cont_expr });
if (block_scope) |*bs| {
try bs.statements.append(&while_node.base);
return try bs.complete(rp.c);
try bs.statements.append(while_node);
return try bs.complete(c);
} else {
_ = try appendToken(rp.c, .Semicolon, ";");
return &while_node.base;
return while_node;
}
}

7
src/translate_c/ast.zig
View File

@ -29,7 +29,11 @@ pub const Node = extern union {
char_literal,
identifier,
@"if",
/// if (!operand) break;
if_not_break,
@"while",
/// while (true) operand
while_true,
@"switch",
@"continue",
@"break",
@ -211,6 +215,8 @@ pub const Node = extern union {
.ptr_to_int,
.enum_to_int,
.empty_array,
.while_true,
.if_not_break,
=> Payload.UnOp,
.add,
@ -399,6 +405,7 @@ pub const Payload = struct {
data: struct {
cond: Node,
body: Node,
cont_expr: ?Node
},
};