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implement %defer and ?defer
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see #110
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@andrewrk
andrewrk committed Feb 6, 2016
1 parent 34a7e6f commit 65a03c5
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Showing 4 changed files with 113 additions and 47 deletions.
10 changes: 10 additions & 0 deletions src/all_types.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -78,8 +78,18 @@ struct ConstExprValue {
} data;
};

enum ReturnKnowledge {
ReturnKnowledgeUnknown,
ReturnKnowledgeKnownError,
ReturnKnowledgeKnownNonError,
ReturnKnowledgeKnownNull,
ReturnKnowledgeKnownNonNull,
ReturnKnowledgeSkipDefers,
};

struct Expr {
TypeTableEntry *type_entry;
ReturnKnowledge return_knowledge;

LLVMValueRef const_llvm_val;
ConstExprValue const_val;
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46 changes: 9 additions & 37 deletions src/analyze.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3693,11 +3693,13 @@ static TypeTableEntry *analyze_cast_expr(CodeGen *g, ImportTableEntry *import, B
// explicit cast from child type of maybe type to maybe type
if (wanted_type->id == TypeTableEntryIdMaybe) {
if (types_match_const_cast_only(wanted_type->data.maybe.child_type, actual_type)) {
get_resolved_expr(node)->return_knowledge = ReturnKnowledgeKnownNonNull;
return resolve_cast(g, context, node, expr_node, wanted_type, CastOpMaybeWrap, true);
} else if (actual_type->id == TypeTableEntryIdNumLitInt ||
actual_type->id == TypeTableEntryIdNumLitFloat)
{
if (num_lit_fits_in_other_type(g, expr_node, wanted_type->data.maybe.child_type)) {
get_resolved_expr(node)->return_knowledge = ReturnKnowledgeKnownNonNull;
return resolve_cast(g, context, node, expr_node, wanted_type, CastOpMaybeWrap, true);
} else {
return g->builtin_types.entry_invalid;
Expand All @@ -3708,11 +3710,13 @@ static TypeTableEntry *analyze_cast_expr(CodeGen *g, ImportTableEntry *import, B
// explicit cast from child type of error type to error type
if (wanted_type->id == TypeTableEntryIdErrorUnion) {
if (types_match_const_cast_only(wanted_type->data.error.child_type, actual_type)) {
get_resolved_expr(node)->return_knowledge = ReturnKnowledgeKnownNonError;
return resolve_cast(g, context, node, expr_node, wanted_type, CastOpErrorWrap, true);
} else if (actual_type->id == TypeTableEntryIdNumLitInt ||
actual_type->id == TypeTableEntryIdNumLitFloat)
{
if (num_lit_fits_in_other_type(g, expr_node, wanted_type->data.error.child_type)) {
get_resolved_expr(node)->return_knowledge = ReturnKnowledgeKnownNonError;
return resolve_cast(g, context, node, expr_node, wanted_type, CastOpErrorWrap, true);
} else {
return g->builtin_types.entry_invalid;
Expand All @@ -3724,6 +3728,7 @@ static TypeTableEntry *analyze_cast_expr(CodeGen *g, ImportTableEntry *import, B
if (wanted_type->id == TypeTableEntryIdErrorUnion &&
actual_type->id == TypeTableEntryIdPureError)
{
get_resolved_expr(node)->return_knowledge = ReturnKnowledgeKnownError;
return resolve_cast(g, context, node, expr_node, wanted_type, CastOpPureErrorWrap, false);
}

Expand Down Expand Up @@ -4602,44 +4607,11 @@ static TypeTableEntry *analyze_defer(CodeGen *g, ImportTableEntry *import, Block

node->data.defer.child_block = new_block_context(node, parent_context);

switch (node->data.defer.kind) {
case ReturnKindUnconditional:
{
TypeTableEntry *resolved_type = analyze_expression(g, import, parent_context, nullptr,
node->data.defer.expr);
validate_voided_expr(g, node->data.defer.expr, resolved_type);
TypeTableEntry *resolved_type = analyze_expression(g, import, parent_context, nullptr,
node->data.defer.expr);
validate_voided_expr(g, node->data.defer.expr, resolved_type);

return g->builtin_types.entry_void;
}
case ReturnKindError:
{
TypeTableEntry *resolved_type = analyze_expression(g, import, parent_context, nullptr,
node->data.defer.expr);
if (resolved_type->id == TypeTableEntryIdInvalid) {
// OK
} else if (resolved_type->id == TypeTableEntryIdErrorUnion) {
// OK
} else {
add_node_error(g, node->data.defer.expr,
buf_sprintf("expected error type, got '%s'", buf_ptr(&resolved_type->name)));
}
return g->builtin_types.entry_void;
}
case ReturnKindMaybe:
{
TypeTableEntry *resolved_type = analyze_expression(g, import, parent_context, nullptr,
node->data.defer.expr);
if (resolved_type->id == TypeTableEntryIdInvalid) {
// OK
} else if (resolved_type->id == TypeTableEntryIdMaybe) {
// OK
} else {
add_node_error(g, node->data.defer.expr,
buf_sprintf("expected maybe type, got '%s'", buf_ptr(&resolved_type->name)));
}
return g->builtin_types.entry_void;
}
}
return g->builtin_types.entry_void;
}

static TypeTableEntry *analyze_string_literal_expr(CodeGen *g, ImportTableEntry *import, BlockContext *context,
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68 changes: 58 additions & 10 deletions src/codegen.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -483,6 +483,7 @@ static LLVMValueRef gen_cast_expr(CodeGen *g, AstNode *node) {
}
case CastOpPureErrorWrap:
assert(wanted_type->id == TypeTableEntryIdErrorUnion);

if (!type_has_bits(wanted_type->data.error.child_type)) {
return expr_val;
} else {
Expand Down Expand Up @@ -1593,18 +1594,48 @@ static LLVMValueRef gen_unwrap_err_expr(CodeGen *g, AstNode *node) {
return phi;
}

static void gen_defers_for_block(CodeGen *g, BlockContext *inner_block, BlockContext *outer_block) {
static void gen_defers_for_block(CodeGen *g, BlockContext *inner_block, BlockContext *outer_block,
bool gen_error_defers, bool gen_maybe_defers)
{
while (inner_block != outer_block) {
if (inner_block->node->type == NodeTypeDefer) {
if (inner_block->node->type == NodeTypeDefer &&
((inner_block->node->data.defer.kind == ReturnKindUnconditional) ||
(gen_error_defers && inner_block->node->data.defer.kind == ReturnKindError) ||
(gen_maybe_defers && inner_block->node->data.defer.kind == ReturnKindMaybe)))
{
gen_expr(g, inner_block->node->data.defer.expr);
}
inner_block = inner_block->parent;
}
}

static LLVMValueRef gen_return(CodeGen *g, AstNode *source_node, LLVMValueRef value) {
gen_defers_for_block(g, source_node->block_context,
source_node->block_context->fn_entry->fn_def_node->block_context);
static int get_conditional_defer_count(BlockContext *inner_block, BlockContext *outer_block) {
int result = 0;
while (inner_block != outer_block) {
if (inner_block->node->type == NodeTypeDefer &&
(inner_block->node->data.defer.kind == ReturnKindError ||
inner_block->node->data.defer.kind == ReturnKindMaybe))
{
result += 1;
}
inner_block = inner_block->parent;
}
return result;
}

static LLVMValueRef gen_return(CodeGen *g, AstNode *source_node, LLVMValueRef value, ReturnKnowledge rk) {
BlockContext *defer_inner_block = source_node->block_context;
BlockContext *defer_outer_block = source_node->block_context->fn_entry->fn_def_node->block_context;
if (rk == ReturnKnowledgeUnknown) {
if (get_conditional_defer_count(defer_inner_block, defer_outer_block) > 0) {
// generate branching code that checks the return value and generates defers
// if the return value is error
zig_panic("TODO");
}
} else if (rk != ReturnKnowledgeSkipDefers) {
gen_defers_for_block(g, defer_inner_block, defer_outer_block,
rk == ReturnKnowledgeKnownError, rk == ReturnKnowledgeKnownNull);
}

TypeTableEntry *return_type = g->cur_fn->type_entry->data.fn.fn_type_id.return_type;
if (handle_is_ptr(return_type)) {
Expand All @@ -1628,7 +1659,23 @@ static LLVMValueRef gen_return_expr(CodeGen *g, AstNode *node) {
switch (node->data.return_expr.kind) {
case ReturnKindUnconditional:
{
return gen_return(g, node, value);
Expr *expr = get_resolved_expr(param_node);
if (expr->const_val.ok) {
if (value_type->id == TypeTableEntryIdErrorUnion) {
if (expr->const_val.data.x_err.err) {
expr->return_knowledge = ReturnKnowledgeKnownError;
} else {
expr->return_knowledge = ReturnKnowledgeKnownNonError;
}
} else if (value_type->id == TypeTableEntryIdMaybe) {
if (expr->const_val.data.x_maybe) {
expr->return_knowledge = ReturnKnowledgeKnownNonNull;
} else {
expr->return_knowledge = ReturnKnowledgeKnownNull;
}
}
}
return gen_return(g, node, value, expr->return_knowledge);
}
case ReturnKindError:
{
Expand All @@ -1653,7 +1700,7 @@ static LLVMValueRef gen_return_expr(CodeGen *g, AstNode *node) {
LLVMPositionBuilderAtEnd(g->builder, return_block);
TypeTableEntry *return_type = g->cur_fn->type_entry->data.fn.fn_type_id.return_type;
if (return_type->id == TypeTableEntryIdPureError) {
gen_return(g, node, err_val);
gen_return(g, node, err_val, ReturnKnowledgeKnownError);
} else if (return_type->id == TypeTableEntryIdErrorUnion) {
if (type_has_bits(return_type->data.error.child_type)) {
assert(g->cur_ret_ptr);
Expand All @@ -1663,7 +1710,7 @@ static LLVMValueRef gen_return_expr(CodeGen *g, AstNode *node) {
LLVMBuildStore(g->builder, err_val, tag_ptr);
LLVMBuildRetVoid(g->builder);
} else {
gen_return(g, node, err_val);
gen_return(g, node, err_val, ReturnKnowledgeKnownError);
}
} else {
zig_unreachable();
Expand Down Expand Up @@ -1834,10 +1881,11 @@ static LLVMValueRef gen_block(CodeGen *g, AstNode *block_node, TypeTableEntry *i
return nullptr;
}

gen_defers_for_block(g, block_node->data.block.nested_block, block_node->data.block.child_block);
gen_defers_for_block(g, block_node->data.block.nested_block, block_node->data.block.child_block,
false, false);

if (implicit_return_type) {
return gen_return(g, block_node, return_value);
return gen_return(g, block_node, return_value, ReturnKnowledgeSkipDefers);
} else {
return return_value;
}
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36 changes: 36 additions & 0 deletions test/run_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1545,6 +1545,42 @@ pub fn main(args: [][]u8) -> %void {
}
)SOURCE", "before\ndefer2\ndefer1\n");


add_simple_case("%defer and it fails", R"SOURCE(
import "std.zig";
pub fn main(args: [][]u8) -> %void {
do_test() %% return;
}
fn do_test() -> %void {
%%stdout.printf("before\n");
defer %%stdout.printf("defer1\n");
%defer %%stdout.printf("deferErr\n");
%return its_gonna_fail();
defer %%stdout.printf("defer3\n");
%%stdout.printf("after\n");
}
error IToldYouItWouldFail;
fn its_gonna_fail() -> %void {
return error.IToldYouItWouldFail;
}
)SOURCE", "before\ndeferErr\ndefer1\n");


add_simple_case("%defer and it passes", R"SOURCE(
import "std.zig";
pub fn main(args: [][]u8) -> %void {
do_test() %% return;
}
fn do_test() -> %void {
%%stdout.printf("before\n");
defer %%stdout.printf("defer1\n");
%defer %%stdout.printf("deferErr\n");
%return its_gonna_pass();
defer %%stdout.printf("defer3\n");
%%stdout.printf("after\n");
}
fn its_gonna_pass() -> %void { }
)SOURCE", "before\nafter\ndefer3\ndefer1\n");
}


Expand Down

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