diff options
| -rw-r--r-- | src/codegen/nasm.c | 115 | ||||
| -rw-r--r-- | tests/codegen_test.c | 28 |
2 files changed, 129 insertions, 14 deletions
diff --git a/src/codegen/nasm.c b/src/codegen/nasm.c index 50c16e2..1062d7a 100644 --- a/src/codegen/nasm.c +++ b/src/codegen/nasm.c @@ -70,6 +70,42 @@ static struct Token resolve_token(struct Emitter* emitter, struct Token token) return token; } +static uint64_t token_to_u64(struct Token token) +{ + uint64_t value = 0; + for (size_t i = 0; i < token.length; i += 1) + value = value * 10 + (uint64_t)(token.start[i] - '0'); + + return value; +} + +static bool buffer_offset(struct ProcDecl* proc, struct Token name, uint64_t* out_offset) +{ + uint64_t cumulative = 0; + for (size_t i = 0; i < proc->body_count; i += 1) + { + struct Statement* statement = &proc->body[i]; + if (statement->kind != STATEMENT_STACK) + continue; + + cumulative += token_to_u64(statement->stack.size); + if (statement->stack.name.length == name.length + && memcmp(statement->stack.name.start, name.start, name.length) == 0) + { + *out_offset = cumulative; + return true; + } + } + + return false; +} + +static bool is_buffer_name(struct Emitter* emitter, struct Token token) +{ + uint64_t offset; + return emitter->proc != NULL && buffer_offset(emitter->proc, token, &offset); +} + static bool emit_operand(struct Emitter* emitter, struct Expr* expr) { switch (expr->kind) @@ -108,28 +144,88 @@ static void emit_divide(struct Emitter* emitter, struct AssignStatement* assign) fprintf(emitter->out, "\n"); } -static void emit_assign(struct Emitter* emitter, struct AssignStatement* assign) +// an expression can be evaluated into a register when it is a single term +// (primary or member), or a left-associative chain of '+'/'-' whose right +// operands are plain operands (never a buffer or a nested binary) +static bool expr_supported(struct Emitter* emitter, struct Expr* expr) { - if (assign->value->kind == EXPR_BINARY) + switch (expr->kind) { - fprintf(emitter->out, "\t; TODO: unsupported assignment\n"); + case EXPR_PRIMARY: + case EXPR_MEMBER: + return true; + case EXPR_BINARY: + if (expr->binary.op.type != TOKEN_PLUS && expr->binary.op.type != TOKEN_MINUS) + return false; + if (expr->binary.right->kind != EXPR_PRIMARY && expr->binary.right->kind != EXPR_MEMBER) + return false; + if (expr->binary.right->kind == EXPR_PRIMARY && is_buffer_name(emitter, expr->binary.right->primary.token)) + return false; + return expr_supported(emitter, expr->binary.left); + } + + return false; +} + +static void emit_expr_into(struct Emitter* emitter, const char* dst, struct Expr* expr) +{ + if (expr->kind == EXPR_BINARY) + { + emit_expr_into(emitter, dst, expr->binary.left); + + const char* mnemonic = expr->binary.op.type == TOKEN_PLUS ? "add" : "sub"; + fprintf(emitter->out, "\t%s %s, ", mnemonic, dst); + emit_operand(emitter, expr->binary.right); + fprintf(emitter->out, "\n"); + return; + } + + if (expr->kind == EXPR_PRIMARY && is_buffer_name(emitter, expr->primary.token)) + { + uint64_t offset; + buffer_offset(emitter->proc, expr->primary.token, &offset); + fprintf(emitter->out, "\tlea %s, [rbp - %llu]\n", dst, (unsigned long long)offset); return; } + fprintf(emitter->out, "\tmov %s, ", dst); + emit_operand(emitter, expr); + fprintf(emitter->out, "\n"); +} + +static void emit_assign(struct Emitter* emitter, struct AssignStatement* assign) +{ if (assign->op.type == TOKEN_SLASH_EQUAL) { emit_divide(emitter, assign); return; } + struct Token target = resolve_token(emitter, assign->target); + + if (assign->op.type == TOKEN_EQUAL && !assign->target_deref) + { + if (!expr_supported(emitter, assign->value)) + { + fprintf(emitter->out, "\t; TODO: unsupported assignment\n"); + return; + } + + char dst[32]; + snprintf(dst, sizeof(dst), "%.*s", (int)target.length, target.start); + emit_expr_into(emitter, dst, assign->value); + return; + } + + // deref store or compound assignment: needs a plain operand, not a buffer or binary const char* mnemonic = assign_mnemonic(assign->op.type); - if (mnemonic == NULL) + bool value_is_buffer = assign->value->kind == EXPR_PRIMARY && is_buffer_name(emitter, assign->value->primary.token); + if (mnemonic == NULL || assign->value->kind == EXPR_BINARY || value_is_buffer) { fprintf(emitter->out, "\t; TODO: unsupported assignment\n"); return; } - struct Token target = resolve_token(emitter, assign->target); if (assign->target_deref) fprintf(emitter->out, "\t%s [%.*s], ", mnemonic, (int)target.length, target.start); else @@ -247,15 +343,6 @@ static void emit_statement(struct Emitter* emitter, struct Statement* statement) } } -static uint64_t token_to_u64(struct Token token) -{ - uint64_t value = 0; - for (size_t i = 0; i < token.length; i += 1) - value = value * 10 + (uint64_t)(token.start[i] - '0'); - - return value; -} - static uint64_t proc_stack_size(struct ProcDecl* proc) { uint64_t total = 0; diff --git a/tests/codegen_test.c b/tests/codegen_test.c index 4f39855..a72638b 100644 --- a/tests/codegen_test.c +++ b/tests/codegen_test.c @@ -176,6 +176,33 @@ static void test_generate_stack_frame(struct TestContext* context) free_program(&program); } +static void test_generate_address_expr(struct TestContext* context) +{ + struct Lexer lexer = create_lexer( + "proc work\n{\nstack buffer[32]\nrsi = buffer + 31\nrdx = buffer + 32 - rsi\n}\n"); + struct Program program; + check(context, parse_program(&lexer, &program)); + + FILE* out = tmpfile(); + generate_nasm(&program, out); + fflush(out); + rewind(out); + + char buffer[1024]; + size_t read = fread(buffer, 1, sizeof(buffer) - 1, out); + buffer[read] = '\0'; + fclose(out); + + check(context, strstr(buffer, "lea rsi, [rbp - 32]") != NULL); + check(context, strstr(buffer, "add rsi, 31") != NULL); + check(context, strstr(buffer, "lea rdx, [rbp - 32]") != NULL); + check(context, strstr(buffer, "add rdx, 32") != NULL); + check(context, strstr(buffer, "sub rdx, rsi") != NULL); + check(context, strstr(buffer, "; TODO") == NULL); + + free_program(&program); +} + void run_codegen_tests(struct TestContext* context) { test_generate_consts_and_data(context); @@ -185,4 +212,5 @@ void run_codegen_tests(struct TestContext* context) test_generate_param_substitution(context); test_generate_divide(context); test_generate_stack_frame(context); + test_generate_address_expr(context); } |