forked from intel/llvm
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
[C2X] N3007 Type inference for object definitions
This patches implements the auto keyword from the N3007 standard
specification.
This allows deducing the type of the variable like in C++:
```
auto nb = 1;
auto chr = 'A';
auto str = "String";
```
The list of statements which allows the usage of auto:
* Basic variables declarations (int, float, double, char, char*...)
* Macros declaring a variable with the auto type
The list of statements which will not work with the auto keyword:
* auto arrays
* sizeof(), alignas()
* auto parameters, auto return type
* auto as a struct/typedef member
* uninitialized auto variables
* auto in an union
* auto as a enum type specifier
* auto casts
* auto in an compound literals
Differential Revision: https://reviews.llvm.org/D133289- Loading branch information
1 parent
58678d3
commit 5d78b78
Showing
11 changed files
with
542 additions
and
11 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,186 @@ | ||
| // RUN: %clang_cc1 -std=c2x -verify -pedantic -Wno-comments %s | ||
|
|
||
| /* WG14 N3007: Yes | ||
| * Type Inference for object definitions | ||
| */ | ||
| void test_qualifiers(int x, const int y, int * restrict z) { | ||
| const auto a = x; | ||
| auto b = y; | ||
| static auto c = 1UL; | ||
| int* pa = &a; // expected-warning {{initializing 'int *' with an expression of type 'const int *' discards qualifiers}} | ||
| const int* pb = &b; | ||
| int* pc = &c; // expected-warning {{incompatible pointer types initializing 'int *' with an expression of type 'unsigned long *'}} | ||
|
|
||
| const int ci = 12; | ||
| auto yup = ci; | ||
| yup = 12; | ||
|
|
||
| auto r_test = z; | ||
|
|
||
| _Static_assert(_Generic(a, int : 1)); | ||
| _Static_assert(_Generic(c, unsigned long : 1)); | ||
| _Static_assert(_Generic(pa, int * : 1)); | ||
| _Static_assert(_Generic(pb, const int * : 1)); | ||
| _Static_assert(_Generic(r_test, int * : 1)); | ||
| } | ||
|
|
||
| void test_atomic(void) { | ||
| _Atomic auto i = 12; // expected-error {{_Atomic cannot be applied to type 'auto' in C23}} | ||
| _Atomic(auto) j = 12; // expected-error {{'auto' not allowed here}} \ | ||
| expected-error {{a type specifier is required for all declarations}} | ||
|
|
||
| _Atomic(int) foo(void); | ||
| auto k = foo(); | ||
|
|
||
| _Static_assert(_Generic(&i, _Atomic auto *: 1)); // expected-error {{_Atomic cannot be applied to type 'auto' in C23}} \ | ||
| expected-error {{'auto' not allowed here}} | ||
| _Static_assert(_Generic(k, int: 1)); | ||
| } | ||
|
|
||
| void test_double(void) { | ||
| double A[3] = { 0 }; | ||
| auto pA = A; | ||
| auto qA = &A; | ||
| auto pi = 3.14; | ||
|
|
||
| _Static_assert(_Generic(A, double * : 1)); | ||
| _Static_assert(_Generic(pA, double * : 1)); | ||
| _Static_assert(_Generic(qA, double (*)[3] : 1)); | ||
| _Static_assert(_Generic(pi, double : 1)); | ||
| } | ||
|
|
||
| int test_auto_param(auto a) { // expected-error {{'auto' not allowed in function prototype}} | ||
| return (int)(a * 2); | ||
| } | ||
|
|
||
| auto test_auto_return(float a, int b) { // expected-error {{'auto' not allowed in function return type}} | ||
| return ((a * b) * (a / b)); | ||
| } | ||
|
|
||
| [[clang::overloadable]] auto test(auto x) { // expected-error {{'auto' not allowed in function prototype}} \ | ||
| expected-error {{'auto' not allowed in function return type}} | ||
| return x; | ||
| } | ||
|
|
||
| void test_sizeof_alignas(void) { | ||
| (void)sizeof(auto); // expected-error {{expected expression}} | ||
| _Alignas(auto) int a[4]; // expected-error {{expected expression}} | ||
| } | ||
|
|
||
| void test_arrary(void) { | ||
| auto a[4]; // expected-error {{'auto' not allowed in array declaration}} | ||
| auto b[] = {1, 2}; // expected-error {{cannot use 'auto' with array in C}} | ||
| } | ||
|
|
||
| void test_initializer_list(void) { | ||
| auto a = {}; // expected-error {{cannot use 'auto' with array in C}} | ||
| auto b = { 0 }; // expected-error {{cannot use 'auto' with array in C}} | ||
| auto c = { 1, }; // expected-error {{cannot use 'auto' with array in C}} | ||
| auto d = { 1 , 2 }; // expected-error {{cannot use 'auto' with array in C}} | ||
| auto e = (int [3]){ 1, 2, 3 }; | ||
| } | ||
|
|
||
| void test_structs(void) { | ||
| // FIXME: Both of these should be diagnosed as invalid underspecified | ||
| // declarations as described in N3006. | ||
| auto p1 = (struct { int a; } *)0; | ||
| struct s; | ||
| auto p2 = (struct s { int a; } *)0; | ||
|
|
||
| struct B { auto b; }; // expected-error {{'auto' not allowed in struct member}} | ||
| } | ||
|
|
||
| void test_typedefs(void) { | ||
| typedef auto auto_type; // expected-error {{'auto' not allowed in typedef}} | ||
|
|
||
| typedef auto (*fp)(void); // expected-error {{'auto' not allowed in typedef}} | ||
| typedef void (*fp)(auto); // expected-error {{'auto' not allowed in function prototype}} | ||
|
|
||
| _Generic(0, auto : 1); // expected-error {{'auto' not allowed here}} | ||
| } | ||
|
|
||
| void test_misc(void) { | ||
| auto something; // expected-error {{declaration of variable 'something' with deduced type 'auto' requires an initializer}} | ||
| auto test_char = 'A'; | ||
| auto test_char_ptr = "test"; | ||
| auto test_char_ptr2[] = "another test"; // expected-warning {{type inference of a declaration other than a plain identifier with optional trailing attributes is a Clang extension}} | ||
| auto auto_size = sizeof(auto); // expected-error {{expected expression}} | ||
|
|
||
| _Static_assert(_Generic(test_char, int : 1)); | ||
| _Static_assert(_Generic(test_char_ptr, char * : 1)); | ||
| _Static_assert(_Generic(test_char_ptr2, char * : 1)); | ||
| } | ||
|
|
||
| void test_no_integer_promotions(void) { | ||
| short s; | ||
| auto a = s; | ||
| _Generic(a, int : 1); // expected-error {{controlling expression type 'short' not compatible with any generic association type}} | ||
| } | ||
|
|
||
| void test_compound_literals(void) { | ||
| auto a = (int){}; | ||
| auto b = (int){ 0 }; | ||
| auto c = (int){ 0, }; | ||
| auto d = (int){ 0, 1 }; // expected-warning {{excess elements in scalar initializer}} | ||
|
|
||
| auto auto_cl = (auto){13}; // expected-error {{expected expression}} | ||
|
|
||
| _Static_assert(_Generic(a, int : 1)); | ||
| _Static_assert(_Generic(b, int : 1)); | ||
| _Static_assert(_Generic(c, int : 1)); | ||
| } | ||
|
|
||
| void test_pointers(void) { | ||
| int a; | ||
| auto *ptr = &a; // expected-warning {{type inference of a declaration other than a plain identifier with optional trailing attributes is a Clang extension}} | ||
| auto *ptr2 = a; // expected-error {{variable 'ptr2' with type 'auto *' has incompatible initializer of type 'int'}} \ | ||
| expected-warning {{type inference of a declaration other than a plain identifier with optional trailing attributes is a Clang extension}} | ||
| auto nptr = nullptr; | ||
|
|
||
| _Static_assert(_Generic(ptr, int * : 1)); | ||
| _Static_assert(_Generic(ptr2, int * : 1)); | ||
| } | ||
|
|
||
| void test_scopes(void) { | ||
| double a = 7; | ||
| double b = 9; | ||
| { | ||
| auto a = a * a; // expected-error {{variable 'a' declared with deduced type 'auto' cannot appear in its own initializer}} \ | ||
| expected-error {{variable 'a' declared with deduced type 'auto' cannot appear in its own initializer}} | ||
| } | ||
| { | ||
| auto b = a * a; | ||
| auto a = b; | ||
|
|
||
| _Static_assert(_Generic(a, double : 1)); | ||
| _Static_assert(_Generic(b, double : 1)); | ||
| } | ||
| } | ||
|
|
||
| void test_loop(void) { | ||
| auto j = 4; | ||
| for (auto i = j; i < 2 * j; i++); | ||
|
|
||
| _Static_assert(_Generic(j, int : 1)); | ||
| } | ||
|
|
||
| #define AUTO_MACRO(_NAME, ARG, ARG2, ARG3) \ | ||
| auto _NAME = ARG + (ARG2 / ARG3); | ||
|
|
||
| // This macro should only work with integers due to the usage of binary operators | ||
| #define AUTO_INT_MACRO(_NAME, ARG, ARG2, ARG3) \ | ||
| auto _NAME = (ARG ^ ARG2) & ARG3; | ||
|
|
||
| void test_macros(int in_int) { | ||
| auto a = in_int + 1; | ||
| AUTO_MACRO(b, 1.3, 2.5f, 3); | ||
| AUTO_INT_MACRO(c, 64, 23, 0xff); | ||
| AUTO_INT_MACRO(not_valid, 51.5, 25, 0xff); // expected-error {{invalid operands to binary expression ('double' and 'int')}} | ||
|
|
||
| auto result = (a + (int)b) - c; | ||
|
|
||
| _Static_assert(_Generic(a, int : 1)); | ||
| _Static_assert(_Generic(b, double : 1)); | ||
| _Static_assert(_Generic(c, int : 1)); | ||
| _Static_assert(_Generic(result, int : 1)); | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,41 @@ | ||
| // RUN: %clang_cc1 -std=c2x -emit-llvm %s -o - | FileCheck %s | ||
|
|
||
| void basic_types(void) { | ||
| auto nb = 4; // CHECK: %nb = alloca i32, align 4 | ||
| auto dbl = 4.3; // CHECK: %dbl = alloca double, align 8 | ||
| auto lng = 4UL; // CHECK: %lng = alloca i{{32|64}}, align {{4|8}} | ||
| auto bl = true; // CHECK: %bl = alloca i8, align 1 | ||
| auto chr = 'A'; // CHECK: %chr = alloca i32, align 4 | ||
| auto str = "Test"; // CHECK: %str = alloca ptr, align 8 | ||
| auto str2[] = "Test"; // CHECK: %str2 = alloca [5 x i8], align 1 | ||
| auto nptr = nullptr; // CHECK: %nptr = alloca ptr, align 8 | ||
| } | ||
|
|
||
| void misc_declarations(void) { | ||
| // FIXME: this should end up being rejected when we implement underspecified | ||
| // declarations in N3006. | ||
| auto strct_ptr = (struct { int a; } *)0; // CHECK: %strct_ptr = alloca ptr, align 8 | ||
| auto int_cl = (int){13}; // CHECK: %int_cl = alloca i32, align 4 | ||
| auto double_cl = (double){2.5}; // CHECK: %double_cl = alloca double, align 8 | ||
|
|
||
| auto se = ({ // CHECK: %se = alloca i32, align 4 | ||
| auto snb = 12; // CHECK: %snb = alloca i32, align 4 | ||
| snb; | ||
| }); | ||
| } | ||
|
|
||
| void loop(void) { | ||
| auto j = 4; // CHECK: %j = alloca i32, align 4 | ||
| for (auto i = j; i < 2 * j; i++); // CHECK: %i = alloca i32, align 4 | ||
| } | ||
|
|
||
| #define AUTO_MACRO(_NAME, ARG, ARG2, ARG3) auto _NAME = ARG + (ARG2 / ARG3); | ||
|
|
||
| #define AUTO_INT_MACRO(_NAME, ARG, ARG2, ARG3) auto _NAME = (ARG ^ ARG2) & ARG3; | ||
|
|
||
| int macros(int in_int) { | ||
| auto a = in_int + 1; // CHECK: %a = alloca i32, align 4 | ||
| AUTO_MACRO(b, 1.3, 2.5f, 3); // CHECK: %b = alloca double, align 8 | ||
| AUTO_INT_MACRO(c, 64, 23, 0xff); // CHECK: %c = alloca i32, align 4 | ||
| return (a + (int)b) - c; // CHECK: ret i32 %sub | ||
| } |
Oops, something went wrong.