authorgravatar for thejoshwolfe@gmail.comJosh Wolfe <thejoshwolfe@gmail.com> 2015-11-30 18:43:45-07:00
committergravatar for thejoshwolfe@gmail.comJosh Wolfe <thejoshwolfe@gmail.com> 2015-11-30 18:43:45-07:00
logabbc3957019c3a12dacd54869ff18b91c3f07699
tree1bba58e7c00e22da24192e8f7c6bc7f2315b28fc
parentef482ece7c047e898fdc2ea15ba4216c15309d0c

implement basics of type checking

1 files changed, 169 insertions(+), 73 deletions(-)

src/analyze.cpp+169-73
...@@ -10,6 +10,12 @@...@@ -10,6 +10,12 @@
10#include "error.hpp"10#include "error.hpp"
11#include "zig_llvm.hpp"11#include "zig_llvm.hpp"
1212
13struct BlockContext {
14 AstNode *node;
15 BlockContext *root;
16 BlockContext *parent;
17};
18
13static void add_node_error(CodeGen *g, AstNode *node, Buf *msg) {19static void add_node_error(CodeGen *g, AstNode *node, Buf *msg) {
14 g->errors.add_one();20 g->errors.add_one();
15 ErrorMsg *last_msg = &g->errors.last();21 ErrorMsg *last_msg = &g->errors.last();
...@@ -229,6 +235,155 @@ static void preview_function_declarations(CodeGen *g, AstNode *node) {...@@ -229,6 +235,155 @@ static void preview_function_declarations(CodeGen *g, AstNode *node) {
229 }235 }
230}236}
231237
238static TypeTableEntry * get_return_type(BlockContext *context) {
239 AstNode *fn_def_node = context->root->node;
240 assert(fn_def_node->type == NodeTypeFnDef);
241 AstNode *fn_proto_node = fn_def_node->data.fn_def.fn_proto;
242 assert(fn_proto_node->type == NodeTypeFnProto);
243 AstNode *return_type_node = fn_proto_node->data.fn_proto.return_type;
244 assert(return_type_node->codegen_node);
245 return return_type_node->codegen_node->data.type_node.entry;
246}
247
248static void check_type_compatibility(CodeGen *g, AstNode *node, TypeTableEntry *expected_type, TypeTableEntry *actual_type) {
249 if (expected_type == actual_type)
250 return; // good
251 if (expected_type == g->builtin_types.entry_invalid || actual_type == g->builtin_types.entry_invalid)
252 return; // already complained
253 if (actual_type == g->builtin_types.entry_unreachable)
254 return; // TODO: is this true?
255
256 // TODO better error message
257 add_node_error(g, node, buf_sprintf("type mismatch."));
258}
259
260static TypeTableEntry * analyze_expression(CodeGen *g, BlockContext *context, TypeTableEntry *expected_type, AstNode *node) {
261 switch (node->type) {
262 case NodeTypeBlock:
263 {
264 // TODO: nested block scopes
265 TypeTableEntry *return_type = g->builtin_types.entry_void;
266 for (int i = 0; i < node->data.block.statements.length; i += 1) {
267 AstNode *child = node->data.block.statements.at(i);
268 if (return_type == g->builtin_types.entry_unreachable) {
269 add_node_error(g, child,
270 buf_sprintf("unreachable code"));
271 break;
272 }
273 return_type = analyze_expression(g, context, nullptr, child);
274 }
275 return return_type;
276 }
277
278 case NodeTypeReturnExpr:
279 {
280 TypeTableEntry *expected_return_type = get_return_type(context);
281 TypeTableEntry *actual_return_type;
282 if (node->data.return_expr.expr) {
283 actual_return_type = analyze_expression(g, context, expected_return_type, node->data.return_expr.expr);
284 } else {
285 actual_return_type = g->builtin_types.entry_void;
286 }
287
288 if (actual_return_type == g->builtin_types.entry_unreachable) {
289 // "return exit(0)" should just be "exit(0)".
290 add_node_error(g, node, buf_sprintf("returning is unreachable."));
291 actual_return_type = g->builtin_types.entry_invalid;
292 }
293
294 check_type_compatibility(g, node, expected_return_type, actual_return_type);
295 return g->builtin_types.entry_unreachable;
296 }
297
298 case NodeTypeBinOpExpr:
299 {
300 // TODO: think about expected types
301 analyze_expression(g, context, expected_type, node->data.bin_op_expr.op1);
302 analyze_expression(g, context, expected_type, node->data.bin_op_expr.op2);
303 return expected_type;
304 }
305
306 case NodeTypeFnCallExpr:
307 {
308 Buf *name = hack_get_fn_call_name(g, node->data.fn_call_expr.fn_ref_expr);
309
310 auto entry = g->fn_table.maybe_get(name);
311 if (!entry) {
312 add_node_error(g, node,
313 buf_sprintf("undefined function: '%s'", buf_ptr(name)));
314 // still analyze the parameters, even though we don't know what to expect
315 for (int i = 0; i < node->data.fn_call_expr.params.length; i += 1) {
316 AstNode *child = node->data.fn_call_expr.params.at(i);
317 analyze_expression(g, context, nullptr, child);
318 }
319
320 return g->builtin_types.entry_invalid;
321 } else {
322 FnTableEntry *fn_table_entry = entry->value;
323 assert(fn_table_entry->proto_node->type == NodeTypeFnProto);
324 AstNodeFnProto *fn_proto = &fn_table_entry->proto_node->data.fn_proto;
325
326 // count parameters
327 int expected_param_count = fn_proto->params.length;
328 int actual_param_count = node->data.fn_call_expr.params.length;
329 if (expected_param_count != actual_param_count) {
330 add_node_error(g, node,
331 buf_sprintf("wrong number of arguments. Expected %d, got %d.",
332 expected_param_count, actual_param_count));
333 }
334
335 // analyze each parameter
336 for (int i = 0; i < node->data.fn_call_expr.params.length; i += 1) {
337 AstNode *child = node->data.fn_call_expr.params.at(i);
338 // determine the expected type for each parameter
339 TypeTableEntry *expected_param_type = nullptr;
340 if (i < fn_proto->params.length) {
341 AstNode *param_decl_node = fn_proto->params.at(i);
342 assert(param_decl_node->type == NodeTypeParamDecl);
343 AstNode *param_type_node = param_decl_node->data.param_decl.type;
344 if (param_type_node->codegen_node)
345 expected_param_type = param_type_node->codegen_node->data.type_node.entry;
346 }
347 analyze_expression(g, context, expected_param_type, child);
348 }
349
350 TypeTableEntry *return_type = fn_proto->return_type->codegen_node->data.type_node.entry;
351 check_type_compatibility(g, node, expected_type, return_type);
352 return return_type;
353 }
354 }
355
356 case NodeTypeNumberLiteral:
357 // TODO: generic literal int type
358 return g->builtin_types.entry_i32;
359
360 case NodeTypeStringLiteral:
361 zig_panic("TODO");
362
363 case NodeTypeUnreachable:
364 return g->builtin_types.entry_unreachable;
365
366 case NodeTypeSymbol:
367 // look up symbol in symbol table
368 zig_panic("TODO");
369
370 case NodeTypeCastExpr:
371 case NodeTypePrefixOpExpr:
372 zig_panic("TODO");
373 case NodeTypeDirective:
374 case NodeTypeFnDecl:
375 case NodeTypeFnProto:
376 case NodeTypeParamDecl:
377 case NodeTypeType:
378 case NodeTypeRoot:
379 case NodeTypeRootExportDecl:
380 case NodeTypeExternBlock:
381 case NodeTypeFnDef:
382 zig_unreachable();
383 }
384 zig_unreachable();
385}
386
232static void check_fn_def_control_flow(CodeGen *g, AstNode *node) {387static void check_fn_def_control_flow(CodeGen *g, AstNode *node) {
233 // Follow the execution flow and make sure the code returns appropriately.388 // Follow the execution flow and make sure the code returns appropriately.
234 // * A `return` statement in an unreachable type function should be an error.389 // * A `return` statement in an unreachable type function should be an error.
...@@ -282,74 +437,6 @@ static void check_fn_def_control_flow(CodeGen *g, AstNode *node) {...@@ -282,74 +437,6 @@ static void check_fn_def_control_flow(CodeGen *g, AstNode *node) {
282 }437 }
283}438}
284439
285static void analyze_expression(CodeGen *g, AstNode *node) {
286 switch (node->type) {
287 case NodeTypeBlock:
288 for (int i = 0; i < node->data.block.statements.length; i += 1) {
289 AstNode *child = node->data.block.statements.at(i);
290 analyze_expression(g, child);
291 }
292 break;
293 case NodeTypeReturnExpr:
294 if (node->data.return_expr.expr) {
295 analyze_expression(g, node->data.return_expr.expr);
296 }
297 break;
298 case NodeTypeBinOpExpr:
299 analyze_expression(g, node->data.bin_op_expr.op1);
300 analyze_expression(g, node->data.bin_op_expr.op2);
301 break;
302 case NodeTypeFnCallExpr:
303 {
304 Buf *name = hack_get_fn_call_name(g, node->data.fn_call_expr.fn_ref_expr);
305
306 auto entry = g->fn_table.maybe_get(name);
307 if (!entry) {
308 add_node_error(g, node,
309 buf_sprintf("undefined function: '%s'", buf_ptr(name)));
310 } else {
311 FnTableEntry *fn_table_entry = entry->value;
312 assert(fn_table_entry->proto_node->type == NodeTypeFnProto);
313 int expected_param_count = fn_table_entry->proto_node->data.fn_proto.params.length;
314 int actual_param_count = node->data.fn_call_expr.params.length;
315 if (expected_param_count != actual_param_count) {
316 add_node_error(g, node,
317 buf_sprintf("wrong number of arguments. Expected %d, got %d.",
318 expected_param_count, actual_param_count));
319 }
320 }
321
322 for (int i = 0; i < node->data.fn_call_expr.params.length; i += 1) {
323 AstNode *child = node->data.fn_call_expr.params.at(i);
324 analyze_expression(g, child);
325 }
326 break;
327 }
328 case NodeTypeCastExpr:
329 zig_panic("TODO");
330 break;
331 case NodeTypePrefixOpExpr:
332 zig_panic("TODO");
333 break;
334 case NodeTypeNumberLiteral:
335 case NodeTypeStringLiteral:
336 case NodeTypeUnreachable:
337 case NodeTypeSymbol:
338 // nothing to do
339 break;
340 case NodeTypeDirective:
341 case NodeTypeFnDecl:
342 case NodeTypeFnProto:
343 case NodeTypeParamDecl:
344 case NodeTypeType:
345 case NodeTypeRoot:
346 case NodeTypeRootExportDecl:
347 case NodeTypeExternBlock:
348 case NodeTypeFnDef:
349 zig_unreachable();
350 }
351}
352
353static void analyze_top_level_declaration(CodeGen *g, AstNode *node) {440static void analyze_top_level_declaration(CodeGen *g, AstNode *node) {
354 switch (node->type) {441 switch (node->type) {
355 case NodeTypeFnDef:442 case NodeTypeFnDef:
...@@ -371,7 +458,13 @@ static void analyze_top_level_declaration(CodeGen *g, AstNode *node) {...@@ -371,7 +458,13 @@ static void analyze_top_level_declaration(CodeGen *g, AstNode *node) {
371 }458 }
372459
373 check_fn_def_control_flow(g, node);460 check_fn_def_control_flow(g, node);
374 analyze_expression(g, node->data.fn_def.body);461
462 BlockContext context;
463 context.node = node;
464 context.root = &context;
465 context.parent = nullptr;
466 TypeTableEntry *expected_type = fn_proto->return_type->codegen_node->data.type_node.entry;
467 analyze_expression(g, &context, expected_type, node->data.fn_def.body);
375 }468 }
376 break;469 break;
377470
...@@ -424,6 +517,12 @@ static void analyze_root(CodeGen *g, AstNode *node) {...@@ -424,6 +517,12 @@ static void analyze_root(CodeGen *g, AstNode *node) {
424}517}
425518
426static void define_primitive_types(CodeGen *g) {519static void define_primitive_types(CodeGen *g) {
520 {
521 // if this type is anywhere in the AST, we should never hit codegen.
522 TypeTableEntry *entry = allocate<TypeTableEntry>(1);
523 buf_init_from_str(&entry->name, "(invalid)");
524 g->builtin_types.entry_invalid = entry;
525 }
427 {526 {
428 TypeTableEntry *entry = allocate<TypeTableEntry>(1);527 TypeTableEntry *entry = allocate<TypeTableEntry>(1);
429 entry->type_ref = LLVMInt8Type();528 entry->type_ref = LLVMInt8Type();
...@@ -450,15 +549,12 @@ static void define_primitive_types(CodeGen *g) {...@@ -450,15 +549,12 @@ static void define_primitive_types(CodeGen *g) {
450 LLVMZigEncoding_DW_ATE_unsigned());549 LLVMZigEncoding_DW_ATE_unsigned());
451 g->type_table.put(&entry->name, entry);550 g->type_table.put(&entry->name, entry);
452 g->builtin_types.entry_void = entry;551 g->builtin_types.entry_void = entry;
453
454 // invalid types are void
455 g->builtin_types.entry_invalid = entry;
456 }552 }
457 {553 {
458 TypeTableEntry *entry = allocate<TypeTableEntry>(1);554 TypeTableEntry *entry = allocate<TypeTableEntry>(1);
459 entry->type_ref = LLVMVoidType();555 entry->type_ref = LLVMVoidType();
460 buf_init_from_str(&entry->name, "unreachable");556 buf_init_from_str(&entry->name, "unreachable");
461 entry->di_type = g->builtin_types.entry_invalid->di_type;557 entry->di_type = g->builtin_types.entry_void->di_type;
462 g->type_table.put(&entry->name, entry);558 g->type_table.put(&entry->name, entry);
463 g->builtin_types.entry_unreachable = entry;559 g->builtin_types.entry_unreachable = entry;
464 }560 }