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add array bounds checking in debug mode

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closes #27
This commit is contained in:
Andrew Kelley 2016-04-26 11:35:56 -07:00
parent 61e6c49bc5
commit d1fa5692c6
5 changed files with 216 additions and 55 deletions
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3
src/all_types.hpp
View File

@ -1051,6 +1051,7 @@ struct FnTableEntry {
bool is_extern;
bool is_test;
bool is_pure;
bool safety_off;
BlockContext *parent_block_context;
FnAnalState anal_state;
@ -1315,6 +1316,8 @@ struct BlockContext {
// if this is true, then this code will not be generated
bool codegen_excluded;
bool safety_off;
};

14
src/analyze.cpp
View File

@ -993,6 +993,18 @@ static void resolve_function_proto(CodeGen *g, AstNode *node, FnTableEntry *fn_t
add_node_error(g, directive_node,
buf_sprintf("invalid function attribute: '%s'", buf_ptr(name)));
}
} else if (buf_eql_str(name, "debug_safety")) {
if (fn_table_entry->is_extern) {
add_node_error(g, directive_node,
buf_sprintf("#debug_safety invalid on extern functions"));
} else {
bool enable;
bool ok = resolve_const_expr_bool(g, import, import->block_context,
&directive_node->data.directive.expr, &enable);
if (ok && !enable) {
fn_table_entry->safety_off = true;
}
}
} else if (buf_eql_str(name, "condition")) {
if (fn_proto->top_level_decl.visib_mod == VisibModExport) {
bool include;
@ -2102,11 +2114,13 @@ BlockContext *new_block_context(AstNode *node, BlockContext *parent) {
context->parent_loop_node = parent->parent_loop_node;
context->c_import_buf = parent->c_import_buf;
context->codegen_excluded = parent->codegen_excluded;
context->safety_off = parent->safety_off;
}
if (node && node->type == NodeTypeFnDef) {
AstNode *fn_proto_node = node->data.fn_def.fn_proto;
context->fn_entry = fn_proto_node->data.fn_proto.fn_table_entry;
context->safety_off = context->fn_entry->safety_off;
} else if (parent) {
context->fn_entry = parent->fn_entry;
}

130
src/codegen.cpp
View File

@ -330,6 +330,46 @@ static LLVMValueRef get_handle_value(CodeGen *g, AstNode *source_node, LLVMValue
}
}
static bool want_debug_safety(CodeGen *g, AstNode *node) {
return !g->is_release_build && !node->block_context->safety_off;
}
static void add_bounds_check(CodeGen *g, AstNode *source_node, LLVMValueRef target_val,
LLVMIntPredicate lower_pred, LLVMValueRef lower_value,
LLVMIntPredicate upper_pred, LLVMValueRef upper_value)
{
if (!lower_value && !upper_value) {
return;
}
if (upper_value && !lower_value) {
lower_value = upper_value;
lower_pred = upper_pred;
upper_value = nullptr;
}
add_debug_source_node(g, source_node);
LLVMBasicBlockRef bounds_check_fail_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "BoundsCheckFail");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "BoundsCheckOk");
LLVMBasicBlockRef lower_ok_block = upper_value ?
LLVMAppendBasicBlock(g->cur_fn->fn_value, "FirstBoundsCheckOk") : ok_block;
LLVMValueRef lower_ok_val = LLVMBuildICmp(g->builder, lower_pred, target_val, lower_value, "");
LLVMBuildCondBr(g->builder, lower_ok_val, lower_ok_block, bounds_check_fail_block);
LLVMPositionBuilderAtEnd(g->builder, bounds_check_fail_block);
LLVMBuildCall(g->builder, g->trap_fn_val, nullptr, 0, "");
LLVMBuildUnreachable(g->builder);
if (upper_value) {
LLVMPositionBuilderAtEnd(g->builder, lower_ok_block);
LLVMValueRef upper_ok_val = LLVMBuildICmp(g->builder, upper_pred, target_val, upper_value, "");
LLVMBuildCondBr(g->builder, upper_ok_val, ok_block, bounds_check_fail_block);
}
LLVMPositionBuilderAtEnd(g->builder, ok_block);
}
static LLVMValueRef gen_err_name(CodeGen *g, AstNode *node) {
assert(node->type == NodeTypeFnCallExpr);
assert(g->generate_error_name_table);
@ -344,25 +384,10 @@ static LLVMValueRef gen_err_name(CodeGen *g, AstNode *node) {
LLVMValueRef err_val = gen_expr(g, err_val_node);
add_debug_source_node(g, node);
if (!g->is_release_build) {
LLVMBasicBlockRef bounds_check_fail_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "BoundsCheckFail");
LLVMBasicBlockRef lower_ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "LowerBoundsCheckOk");
LLVMBasicBlockRef ok_block = LLVMAppendBasicBlock(g->cur_fn->fn_value, "BoundsCheckOk");
if (want_debug_safety(g, node)) {
LLVMValueRef zero = LLVMConstNull(LLVMTypeOf(err_val));
LLVMValueRef is_zero_val = LLVMBuildICmp(g->builder, LLVMIntEQ, err_val, zero, "");
LLVMBuildCondBr(g->builder, is_zero_val, bounds_check_fail_block, lower_ok_block);
LLVMPositionBuilderAtEnd(g->builder, bounds_check_fail_block);
LLVMBuildCall(g->builder, g->trap_fn_val, nullptr, 0, "");
LLVMBuildUnreachable(g->builder);
LLVMPositionBuilderAtEnd(g->builder, lower_ok_block);
LLVMValueRef end_val = LLVMConstInt(LLVMTypeOf(err_val), g->error_decls.length, false);
LLVMValueRef is_too_big_val = LLVMBuildICmp(g->builder, LLVMIntUGE, err_val, end_val, "");
LLVMBuildCondBr(g->builder, is_too_big_val, bounds_check_fail_block, ok_block);
LLVMPositionBuilderAtEnd(g->builder, ok_block);
add_bounds_check(g, node, err_val, LLVMIntNE, zero, LLVMIntULT, end_val);
}
LLVMValueRef indices[] = {
@ -869,6 +894,11 @@ static LLVMValueRef gen_array_elem_ptr(CodeGen *g, AstNode *source_node, LLVMVal
}
if (array_type->id == TypeTableEntryIdArray) {
if (want_debug_safety(g, source_node)) {
LLVMValueRef end = LLVMConstInt(g->builtin_types.entry_isize->type_ref,
array_type->data.array.len, false);
add_bounds_check(g, source_node, subscript_value, LLVMIntEQ, nullptr, LLVMIntULT, end);
}
LLVMValueRef indices[] = {
LLVMConstNull(g->builtin_types.entry_isize->type_ref),
subscript_value
@ -887,6 +917,15 @@ static LLVMValueRef gen_array_elem_ptr(CodeGen *g, AstNode *source_node, LLVMVal
assert(LLVMGetTypeKind(LLVMTypeOf(array_ptr)) == LLVMPointerTypeKind);
assert(LLVMGetTypeKind(LLVMGetElementType(LLVMTypeOf(array_ptr))) == LLVMStructTypeKind);
if (want_debug_safety(g, source_node)) {
add_debug_source_node(g, source_node);
int len_index = array_type->data.structure.fields[1].gen_index;
assert(len_index >= 0);
LLVMValueRef len_ptr = LLVMBuildStructGEP(g->builder, array_ptr, len_index, "");
LLVMValueRef len = LLVMBuildLoad(g->builder, len_ptr, "");
add_bounds_check(g, source_node, subscript_value, LLVMIntEQ, nullptr, LLVMIntULT, len);
}
add_debug_source_node(g, source_node);
int ptr_index = array_type->data.structure.fields[0].gen_index;
assert(ptr_index >= 0);
@ -907,7 +946,6 @@ static LLVMValueRef gen_array_ptr(CodeGen *g, AstNode *node) {
LLVMValueRef array_ptr = gen_array_base_ptr(g, array_expr_node);
LLVMValueRef subscript_value = gen_expr(g, node->data.array_access_expr.subscript);
return gen_array_elem_ptr(g, node, array_ptr, array_type, subscript_value);
}
@ -969,6 +1007,15 @@ static LLVMValueRef gen_slice_expr(CodeGen *g, AstNode *node) {
end_val = LLVMConstInt(g->builtin_types.entry_isize->type_ref, array_type->data.array.len, false);
}
if (want_debug_safety(g, node)) {
add_bounds_check(g, node, start_val, LLVMIntEQ, nullptr, LLVMIntULE, end_val);
if (node->data.slice_expr.end) {
LLVMValueRef array_end = LLVMConstInt(g->builtin_types.entry_isize->type_ref,
array_type->data.array.len, false);
add_bounds_check(g, node, end_val, LLVMIntEQ, nullptr, LLVMIntULE, array_end);
}
}
add_debug_source_node(g, node);
LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, 0, "");
LLVMValueRef indices[] = {
@ -987,6 +1034,10 @@ static LLVMValueRef gen_slice_expr(CodeGen *g, AstNode *node) {
LLVMValueRef start_val = gen_expr(g, node->data.slice_expr.start);
LLVMValueRef end_val = gen_expr(g, node->data.slice_expr.end);
if (want_debug_safety(g, node)) {
add_bounds_check(g, node, start_val, LLVMIntEQ, nullptr, LLVMIntULE, end_val);
}
add_debug_source_node(g, node);
LLVMValueRef ptr_field_ptr = LLVMBuildStructGEP(g->builder, tmp_struct_ptr, 0, "");
LLVMValueRef slice_start_ptr = LLVMBuildInBoundsGEP(g->builder, array_ptr, &start_val, 1, "");
@ -1002,22 +1053,33 @@ static LLVMValueRef gen_slice_expr(CodeGen *g, AstNode *node) {
assert(LLVMGetTypeKind(LLVMTypeOf(array_ptr)) == LLVMPointerTypeKind);
assert(LLVMGetTypeKind(LLVMGetElementType(LLVMTypeOf(array_ptr))) == LLVMStructTypeKind);
int ptr_index = array_type->data.structure.fields[0].gen_index;
assert(ptr_index >= 0);
int len_index = array_type->data.structure.fields[1].gen_index;
assert(len_index >= 0);
LLVMValueRef prev_end = nullptr;
if (!node->data.slice_expr.end || want_debug_safety(g, node)) {
add_debug_source_node(g, node);
LLVMValueRef src_len_ptr = LLVMBuildStructGEP(g->builder, array_ptr, len_index, "");
prev_end = LLVMBuildLoad(g->builder, src_len_ptr, "");
}
LLVMValueRef start_val = gen_expr(g, node->data.slice_expr.start);
LLVMValueRef end_val;
if (node->data.slice_expr.end) {
end_val = gen_expr(g, node->data.slice_expr.end);
} else {
add_debug_source_node(g, node);
int len_index = array_type->data.structure.fields[1].gen_index;
assert(len_index >= 0);
LLVMValueRef src_len_ptr = LLVMBuildStructGEP(g->builder, array_ptr, len_index, "");
end_val = LLVMBuildLoad(g->builder, src_len_ptr, "");
end_val = prev_end;
}
int ptr_index = array_type->data.structure.fields[0].gen_index;
assert(ptr_index >= 0);
int len_index = array_type->data.structure.fields[1].gen_index;
assert(len_index >= 0);
if (want_debug_safety(g, node)) {
assert(prev_end);
add_bounds_check(g, node, start_val, LLVMIntEQ, nullptr, LLVMIntULE, end_val);
if (node->data.slice_expr.end) {
add_bounds_check(g, node, end_val, LLVMIntEQ, nullptr, LLVMIntULE, prev_end);
}
}
add_debug_source_node(g, node);
LLVMValueRef src_ptr_ptr = LLVMBuildStructGEP(g->builder, array_ptr, ptr_index, "");
@ -1225,7 +1287,7 @@ static LLVMValueRef gen_prefix_op_expr(CodeGen *g, AstNode *node) {
assert(expr_type->id == TypeTableEntryIdErrorUnion);
TypeTableEntry *child_type = expr_type->data.error.child_type;
if (!g->is_release_build) {
if (want_debug_safety(g, node)) {
LLVMValueRef err_val;
if (type_has_bits(child_type)) {
add_debug_source_node(g, node);
@ -1263,7 +1325,7 @@ static LLVMValueRef gen_prefix_op_expr(CodeGen *g, AstNode *node) {
assert(expr_type->id == TypeTableEntryIdMaybe);
TypeTableEntry *child_type = expr_type->data.maybe.child_type;
if (!g->is_release_build) {
if (want_debug_safety(g, node)) {
add_debug_source_node(g, node);
LLVMValueRef cond_val;
if (child_type->id == TypeTableEntryIdPointer ||
@ -2261,7 +2323,7 @@ static LLVMValueRef gen_container_init_expr(CodeGen *g, AstNode *node) {
} else if (type_entry->id == TypeTableEntryIdUnreachable) {
assert(node->data.container_init_expr.entries.length == 0);
add_debug_source_node(g, node);
if (!g->is_release_build) {
if (want_debug_safety(g, node)) {
LLVMBuildCall(g->builder, g->trap_fn_val, nullptr, 0, "");
}
LLVMBuildUnreachable(g->builder);
@ -2575,7 +2637,7 @@ static LLVMValueRef gen_var_decl_raw(CodeGen *g, AstNode *source_node, AstNodeVa
}
}
}
if (!ignore_uninit && !g->is_release_build) {
if (!ignore_uninit && want_debug_safety(g, source_node)) {
TypeTableEntry *isize = g->builtin_types.entry_isize;
uint64_t size_bytes = LLVMStoreSizeOfType(g->target_data_ref, variable->type->type_ref);
uint64_t align_bytes = get_memcpy_align(g, variable->type);
@ -2790,7 +2852,7 @@ static LLVMValueRef gen_switch_expr(CodeGen *g, AstNode *node) {
if (!else_prong) {
LLVMPositionBuilderAtEnd(g->builder, else_block);
add_debug_source_node(g, node);
if (!g->is_release_build) {
if (want_debug_safety(g, node)) {
LLVMBuildCall(g->builder, g->trap_fn_val, nullptr, 0, "");
}
LLVMBuildUnreachable(g->builder);
@ -3383,6 +3445,10 @@ static void do_code_gen(CodeGen *g) {
// Generate the list of test function pointers.
if (g->is_test_build) {
if (g->test_fn_count == 0) {
fprintf(stderr, "No tests to run.\n");
exit(0);
}
assert(g->test_fn_count > 0);
assert(next_test_index == g->test_fn_count);

2
std/builtin.zig
View File

@ -1,6 +1,7 @@
// These functions are provided when not linking against libc because LLVM
// sometimes generates code that calls them.
#debug_safety(false)
export fn memset(dest: &u8, c: u8, n: isize) -> &u8 {
var index : @typeof(n) = 0;
while (index != n) {
@ -10,6 +11,7 @@ export fn memset(dest: &u8, c: u8, n: isize) -> &u8 {
return dest;
}
#debug_safety(false)
export fn memcpy(noalias dest: &u8, noalias src: &const u8, n: isize) -> &u8 {
var index : @typeof(n) = 0;
while (index != n) {

122
test/run_tests.cpp
View File

@ -27,6 +27,7 @@ struct TestCase {
ZigList<const char *> program_args;
bool is_parseh;
bool is_self_hosted;
bool is_debug_safety;
};
static ZigList<TestCase*> test_cases = {0};
@ -122,6 +123,55 @@ static TestCase *add_compile_fail_case(const char *case_name, const char *source
return test_case;
}
static void add_debug_safety_case(const char *case_name, const char *source) {
{
TestCase *test_case = allocate<TestCase>(1);
test_case->is_debug_safety = true;
test_case->case_name = buf_ptr(buf_sprintf("%s (debug)", case_name));
test_case->source_files.resize(1);
test_case->source_files.at(0).relative_path = tmp_source_path;
test_case->source_files.at(0).source_code = source;
test_case->compiler_args.append("build");
test_case->compiler_args.append(tmp_source_path);
test_case->compiler_args.append("--name");
test_case->compiler_args.append("test");
test_case->compiler_args.append("--export");
test_case->compiler_args.append("exe");
test_case->compiler_args.append("--output");
test_case->compiler_args.append(tmp_exe_path);
test_cases.append(test_case);
}
{
TestCase *test_case = allocate<TestCase>(1);
test_case->case_name = buf_ptr(buf_sprintf("%s (release)", case_name));
test_case->source_files.resize(1);
test_case->source_files.at(0).relative_path = tmp_source_path;
test_case->source_files.at(0).source_code = source;
test_case->output = "";
test_case->compiler_args.append("build");
test_case->compiler_args.append(tmp_source_path);
test_case->compiler_args.append("--name");
test_case->compiler_args.append("test");
test_case->compiler_args.append("--export");
test_case->compiler_args.append("exe");
test_case->compiler_args.append("--output");
test_case->compiler_args.append(tmp_exe_path);
test_case->compiler_args.append("--release");
test_cases.append(test_case);
}
}
static TestCase *add_parseh_case(const char *case_name, const char *source, int count, ...) {
va_list ap;
va_start(ap, count);
@ -1247,6 +1297,22 @@ fn bar() -> i32 { 2 }
)SOURCE", 1, ".tmp_source.zig:3:15: error: unable to infer expression type");
}
static void add_debug_safety_test_cases(void) {
add_debug_safety_case("out of bounds slice access", R"SOURCE(
pub fn main(args: [][]u8) -> %void {
const a = []i32{1, 2, 3, 4};
baz(bar(a));
}
#static_eval_enable(false)
fn bar(a: []i32) -> i32 {
a[4]
}
#static_eval_enable(false)
fn baz(a: i32) {}
)SOURCE");
}
//////////////////////////////////////////////////////////////////////////////
static void add_parseh_test_cases(void) {
@ -1455,6 +1521,14 @@ static void print_compiler_invocation(TestCase *test_case) {
printf("\n");
}
static void print_exe_invocation(TestCase *test_case) {
printf("%s", tmp_exe_path);
for (int i = 0; i < test_case->program_args.length; i += 1) {
printf(" %s", test_case->program_args.at(i));
}
printf("\n");
}
static void run_test(TestCase *test_case) {
if (test_case->is_self_hosted) {
return run_self_hosted_test();
@ -1531,32 +1605,33 @@ static void run_test(TestCase *test_case) {
Buf program_stdout = BUF_INIT;
os_exec_process(tmp_exe_path, test_case->program_args, &return_code, &program_stderr, &program_stdout);
if (return_code != 0) {
printf("\nProgram exited with return code %d:\n", return_code);
print_compiler_invocation(test_case);
printf("%s", tmp_exe_path);
for (int i = 0; i < test_case->program_args.length; i += 1) {
printf(" %s", test_case->program_args.at(i));
if (test_case->is_debug_safety) {
if (return_code == 0) {
printf("\nProgram expected to hit debug trap but exited with return code 0\n");
print_compiler_invocation(test_case);
print_exe_invocation(test_case);
exit(1);
}
} else {
if (return_code != 0) {
printf("\nProgram exited with return code %d:\n", return_code);
print_compiler_invocation(test_case);
print_exe_invocation(test_case);
printf("%s\n", buf_ptr(&program_stderr));
exit(1);
}
printf("\n");
printf("%s\n", buf_ptr(&program_stderr));
exit(1);
}
if (!buf_eql_str(&program_stdout, test_case->output)) {
printf("\n");
print_compiler_invocation(test_case);
printf("%s", tmp_exe_path);
for (int i = 0; i < test_case->program_args.length; i += 1) {
printf(" %s", test_case->program_args.at(i));
if (!buf_eql_str(&program_stdout, test_case->output)) {
printf("\n");
print_compiler_invocation(test_case);
print_exe_invocation(test_case);
printf("==== Test failed. Expected output: ====\n");
printf("%s\n", test_case->output);
printf("========= Actual output: ==============\n");
printf("%s\n", buf_ptr(&program_stdout));
printf("=======================================\n");
exit(1);
}
printf("\n");
printf("==== Test failed. Expected output: ====\n");
printf("%s\n", test_case->output);
printf("========= Actual output: ==============\n");
printf("%s\n", buf_ptr(&program_stdout));
printf("=======================================\n");
exit(1);
}
}
@ -1606,6 +1681,7 @@ int main(int argc, char **argv) {
}
}
add_compiling_test_cases();
add_debug_safety_test_cases();
add_compile_failure_test_cases();
add_parseh_test_cases();
add_self_hosted_tests();