1 | //! Defines primitive types that match C's type definitions for FFI compatibility. |
2 | //! |
3 | //! This module is intentionally standalone to facilitate parsing when retrieving |
4 | //! core C types. |
5 | |
6 | macro_rules! type_alias { |
7 | { |
8 | $Docfile:tt, $Alias:ident = $Real:ty; |
9 | $( $Cfg:tt )* |
10 | } => { |
11 | #[doc = include_str!($Docfile)] |
12 | $( $Cfg )* |
13 | #[stable(feature = "core_ffi_c" , since = "1.64.0" )] |
14 | pub type $Alias = $Real; |
15 | } |
16 | } |
17 | |
18 | type_alias! { "c_char.md" , c_char = c_char_definition::c_char; #[doc (cfg(all()))] } |
19 | |
20 | type_alias! { "c_schar.md" , c_schar = i8; } |
21 | type_alias! { "c_uchar.md" , c_uchar = u8; } |
22 | type_alias! { "c_short.md" , c_short = i16; } |
23 | type_alias! { "c_ushort.md" , c_ushort = u16; } |
24 | |
25 | type_alias! { "c_int.md" , c_int = c_int_definition::c_int; #[doc (cfg(all()))] } |
26 | type_alias! { "c_uint.md" , c_uint = c_int_definition::c_uint; #[doc (cfg(all()))] } |
27 | |
28 | type_alias! { "c_long.md" , c_long = c_long_definition::c_long; #[doc (cfg(all()))] } |
29 | type_alias! { "c_ulong.md" , c_ulong = c_long_definition::c_ulong; #[doc (cfg(all()))] } |
30 | |
31 | type_alias! { "c_longlong.md" , c_longlong = i64; } |
32 | type_alias! { "c_ulonglong.md" , c_ulonglong = u64; } |
33 | |
34 | type_alias! { "c_float.md" , c_float = f32; } |
35 | type_alias! { "c_double.md" , c_double = f64; } |
36 | |
37 | mod c_char_definition { |
38 | crate::cfg_match! { |
39 | // These are the targets on which c_char is unsigned. Usually the |
40 | // signedness is the same for all target_os values on a given architecture |
41 | // but there are some exceptions (see isSignedCharDefault() in clang). |
42 | // aarch64: |
43 | // Section 10 "Arm C and C++ language mappings" in Procedure Call Standard for the Arm® |
44 | // 64-bit Architecture (AArch64) says C/C++ char is unsigned byte. |
45 | // https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs64/aapcs64.rst#arm-c-and-c-language-mappings |
46 | // arm: |
47 | // Section 8 "Arm C and C++ Language Mappings" in Procedure Call Standard for the Arm® |
48 | // Architecture says C/C++ char is unsigned byte. |
49 | // https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs32/aapcs32.rst#arm-c-and-c-language-mappings |
50 | // csky: |
51 | // Section 2.1.2 "Primary Data Type" in C-SKY V2 CPU Applications Binary Interface |
52 | // Standards Manual says ANSI C char is unsigned byte. |
53 | // https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/C-SKY_V2_CPU_Applications_Binary_Interface_Standards_Manual.pdf |
54 | // Note: this doesn't seem to match Clang's default (https://github.com/rust-lang/rust/issues/129945). |
55 | // hexagon: |
56 | // Section 3.1 "Basic data type" in Qualcomm Hexagon™ Application |
57 | // Binary Interface User Guide says "By default, the `char` data type is unsigned." |
58 | // https://docs.qualcomm.com/bundle/publicresource/80-N2040-23_REV_K_Qualcomm_Hexagon_Application_Binary_Interface_User_Guide.pdf |
59 | // msp430: |
60 | // Section 2.1 "Basic Types" in MSP430 Embedded Application Binary |
61 | // Interface says "The char type is unsigned by default". |
62 | // https://www.ti.com/lit/an/slaa534a/slaa534a.pdf |
63 | // powerpc/powerpc64: |
64 | // - PPC32 SysV: "Table 3-1 Scalar Types" in System V Application Binary Interface PowerPC |
65 | // Processor Supplement says ANSI C char is unsigned byte |
66 | // https://refspecs.linuxfoundation.org/elf/elfspec_ppc.pdf |
67 | // - PPC64 ELFv1: Section 3.1.4 "Fundamental Types" in 64-bit PowerPC ELF Application |
68 | // Binary Interface Supplement 1.9 says ANSI C is unsigned byte |
69 | // https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUND-TYPE |
70 | // - PPC64 ELFv2: Section 2.1.2.2 "Fundamental Types" in 64-Bit ELF V2 ABI Specification |
71 | // says char is unsigned byte |
72 | // https://openpowerfoundation.org/specifications/64bitelfabi/ |
73 | // - AIX: XL C for AIX Language Reference says "By default, char behaves like an unsigned char." |
74 | // https://www.ibm.com/docs/en/xl-c-aix/13.1.3?topic=specifiers-character-types |
75 | // riscv32/riscv64: |
76 | // C/C++ type representations section in RISC-V Calling Conventions |
77 | // page in RISC-V ELF psABI Document says "char is unsigned." |
78 | // https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/draft-20240829-13bfa9f54634cb60d86b9b333e109f077805b4b3/riscv-cc.adoc#cc-type-representations |
79 | // s390x: |
80 | // - ELF: "Table 1.1.: Scalar types" in ELF Application Binary Interface s390x Supplement |
81 | // Version 1.6.1 categorize ISO C char in unsigned integer |
82 | // https://github.com/IBM/s390x-abi/releases/tag/v1.6.1 |
83 | // - z/OS: XL C/C++ Language Reference says: "By default, char behaves like an unsigned char." |
84 | // https://www.ibm.com/docs/en/zos/3.1.0?topic=specifiers-character-types |
85 | // xtensa: |
86 | // Section 2.17.1 "Data Types and Alignment" of Xtensa LX Microprocessor Overview handbook |
87 | // says "`char` type is unsigned by default". |
88 | // https://loboris.eu/ESP32/Xtensa_lx%20Overview%20handbook.pdf |
89 | // |
90 | // On the following operating systems, c_char is signed by default, regardless of architecture. |
91 | // Darwin (macOS, iOS, etc.): |
92 | // Apple targets' c_char is signed by default even on arm |
93 | // https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Handle-data-types-and-data-alignment-properly |
94 | // Windows: |
95 | // Windows MSVC C++ Language Reference says "Microsoft-specific: Variables of type char |
96 | // are promoted to int as if from type signed char by default, unless the /J compilation |
97 | // option is used." |
98 | // https://learn.microsoft.com/en-us/cpp/cpp/fundamental-types-cpp?view=msvc-170#character-types |
99 | // Vita: |
100 | // Chars are signed by default on the Vita, and VITASDK follows that convention. |
101 | // https://github.com/vitasdk/buildscripts/blob/09c533b771591ecde88864b6acad28ffb688dbd4/patches/gcc/0001-gcc-10.patch#L33-L34 |
102 | // |
103 | // L4Re: |
104 | // The kernel builds with -funsigned-char on all targets (but userspace follows the |
105 | // architecture defaults). As we only have a target for userspace apps so there are no |
106 | // special cases for L4Re below. |
107 | // https://github.com/rust-lang/rust/pull/132975#issuecomment-2484645240 |
108 | all( |
109 | not(windows), |
110 | not(target_vendor = "apple" ), |
111 | not(target_os = "vita" ), |
112 | any( |
113 | target_arch = "aarch64" , |
114 | target_arch = "arm" , |
115 | target_arch = "csky" , |
116 | target_arch = "hexagon" , |
117 | target_arch = "msp430" , |
118 | target_arch = "powerpc" , |
119 | target_arch = "powerpc64" , |
120 | target_arch = "riscv32" , |
121 | target_arch = "riscv64" , |
122 | target_arch = "s390x" , |
123 | target_arch = "xtensa" , |
124 | ) |
125 | ) => { |
126 | pub(super) type c_char = u8; |
127 | } |
128 | // On every other target, c_char is signed. |
129 | _ => { |
130 | pub(super) type c_char = i8; |
131 | } |
132 | } |
133 | } |
134 | |
135 | mod c_long_definition { |
136 | crate::cfg_match! { |
137 | any( |
138 | all(target_pointer_width = "64" , not(windows)), |
139 | // wasm32 Linux ABI uses 64-bit long |
140 | all(target_arch = "wasm32" , target_os = "linux" ) |
141 | ) => { |
142 | pub(super) type c_long = i64; |
143 | pub(super) type c_ulong = u64; |
144 | } |
145 | _ => { |
146 | // The minimal size of `long` in the C standard is 32 bits |
147 | pub(super) type c_long = i32; |
148 | pub(super) type c_ulong = u32; |
149 | } |
150 | } |
151 | } |
152 | |
153 | /// Equivalent to C's `size_t` type, from `stddef.h` (or `cstddef` for C++). |
154 | /// |
155 | /// This type is currently always [`usize`], however in the future there may be |
156 | /// platforms where this is not the case. |
157 | #[unstable (feature = "c_size_t" , issue = "88345" )] |
158 | pub type c_size_t = usize; |
159 | |
160 | /// Equivalent to C's `ptrdiff_t` type, from `stddef.h` (or `cstddef` for C++). |
161 | /// |
162 | /// This type is currently always [`isize`], however in the future there may be |
163 | /// platforms where this is not the case. |
164 | #[unstable (feature = "c_size_t" , issue = "88345" )] |
165 | pub type c_ptrdiff_t = isize; |
166 | |
167 | /// Equivalent to C's `ssize_t` (on POSIX) or `SSIZE_T` (on Windows) type. |
168 | /// |
169 | /// This type is currently always [`isize`], however in the future there may be |
170 | /// platforms where this is not the case. |
171 | #[unstable (feature = "c_size_t" , issue = "88345" )] |
172 | pub type c_ssize_t = isize; |
173 | |
174 | mod c_int_definition { |
175 | crate::cfg_match! { |
176 | any(target_arch = "avr" , target_arch = "msp430" ) => { |
177 | pub(super) type c_int = i16; |
178 | pub(super) type c_uint = u16; |
179 | } |
180 | _ => { |
181 | pub(super) type c_int = i32; |
182 | pub(super) type c_uint = u32; |
183 | } |
184 | } |
185 | } |
186 | |