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Extract core::ffi primitives to a separate (internal) module #136334

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Extract core::ffi primitives to a separate (internal) module #136334

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175 changes: 7 additions & 168 deletions library/core/src/ffi/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -37,175 +37,14 @@ pub use self::va_list::{VaList, VaListImpl};
)]
pub mod va_list;

macro_rules! type_alias {
{
$Docfile:tt, $Alias:ident = $Real:ty;
$( $Cfg:tt )*
} => {
#[doc = include_str!($Docfile)]
$( $Cfg )*
#[stable(feature = "core_ffi_c", since = "1.64.0")]
pub type $Alias = $Real;
}
}

type_alias! { "c_char.md", c_char = c_char_definition::c_char; #[doc(cfg(all()))] }

type_alias! { "c_schar.md", c_schar = i8; }
type_alias! { "c_uchar.md", c_uchar = u8; }
type_alias! { "c_short.md", c_short = i16; }
type_alias! { "c_ushort.md", c_ushort = u16; }

type_alias! { "c_int.md", c_int = c_int_definition::c_int; #[doc(cfg(all()))] }
type_alias! { "c_uint.md", c_uint = c_int_definition::c_uint; #[doc(cfg(all()))] }

type_alias! { "c_long.md", c_long = c_long_definition::c_long; #[doc(cfg(all()))] }
type_alias! { "c_ulong.md", c_ulong = c_long_definition::c_ulong; #[doc(cfg(all()))] }

type_alias! { "c_longlong.md", c_longlong = i64; }
type_alias! { "c_ulonglong.md", c_ulonglong = u64; }

type_alias! { "c_float.md", c_float = f32; }
type_alias! { "c_double.md", c_double = f64; }

/// Equivalent to C's `size_t` type, from `stddef.h` (or `cstddef` for C++).
///
/// This type is currently always [`usize`], however in the future there may be
/// platforms where this is not the case.
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_size_t = usize;

/// Equivalent to C's `ptrdiff_t` type, from `stddef.h` (or `cstddef` for C++).
///
/// This type is currently always [`isize`], however in the future there may be
/// platforms where this is not the case.
mod primitives;
#[stable(feature = "core_ffi_c", since = "1.64.0")]
pub use self::primitives::{
c_char, c_double, c_float, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint,
c_ulong, c_ulonglong, c_ushort,
};
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_ptrdiff_t = isize;

/// Equivalent to C's `ssize_t` (on POSIX) or `SSIZE_T` (on Windows) type.
///
/// This type is currently always [`isize`], however in the future there may be
/// platforms where this is not the case.
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_ssize_t = isize;

mod c_char_definition {
cfg_if! {
// These are the targets on which c_char is unsigned. Usually the
// signedness is the same for all target_os values on a given architecture
// but there are some exceptions (see isSignedCharDefault() in clang).
//
// aarch64:
// Section 10 "Arm C and C++ language mappings" in Procedure Call Standard for the Arm®
// 64-bit Architecture (AArch64) says C/C++ char is unsigned byte.
// https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs64/aapcs64.rst#arm-c-and-c-language-mappings
// arm:
// Section 8 "Arm C and C++ Language Mappings" in Procedure Call Standard for the Arm®
// Architecture says C/C++ char is unsigned byte.
// https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs32/aapcs32.rst#arm-c-and-c-language-mappings
// csky:
// Section 2.1.2 "Primary Data Type" in C-SKY V2 CPU Applications Binary Interface
// Standards Manual says ANSI C char is unsigned byte.
// https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/C-SKY_V2_CPU_Applications_Binary_Interface_Standards_Manual.pdf
// Note: this doesn't seem to match Clang's default (https://github.com/rust-lang/rust/issues/129945).
// hexagon:
// Section 3.1 "Basic data type" in Qualcomm Hexagon™ Application
// Binary Interface User Guide says "By default, the `char` data type is unsigned."
// https://docs.qualcomm.com/bundle/publicresource/80-N2040-23_REV_K_Qualcomm_Hexagon_Application_Binary_Interface_User_Guide.pdf
// msp430:
// Section 2.1 "Basic Types" in MSP430 Embedded Application Binary
// Interface says "The char type is unsigned by default".
// https://www.ti.com/lit/an/slaa534a/slaa534a.pdf
// powerpc/powerpc64:
// - PPC32 SysV: "Table 3-1 Scalar Types" in System V Application Binary Interface PowerPC
// Processor Supplement says ANSI C char is unsigned byte
// https://refspecs.linuxfoundation.org/elf/elfspec_ppc.pdf
// - PPC64 ELFv1: Section 3.1.4 "Fundamental Types" in 64-bit PowerPC ELF Application
// Binary Interface Supplement 1.9 says ANSI C is unsigned byte
// https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUND-TYPE
// - PPC64 ELFv2: Section 2.1.2.2 "Fundamental Types" in 64-Bit ELF V2 ABI Specification
// says char is unsigned byte
// https://openpowerfoundation.org/specifications/64bitelfabi/
// - AIX: XL C for AIX Language Reference says "By default, char behaves like an unsigned char."
// https://www.ibm.com/docs/en/xl-c-aix/13.1.3?topic=specifiers-character-types
// riscv32/riscv64:
// C/C++ type representations section in RISC-V Calling Conventions
// page in RISC-V ELF psABI Document says "char is unsigned."
// https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/draft-20240829-13bfa9f54634cb60d86b9b333e109f077805b4b3/riscv-cc.adoc#cc-type-representations
// s390x:
// - ELF: "Table 1.1.: Scalar types" in ELF Application Binary Interface s390x Supplement
// Version 1.6.1 categorize ISO C char in unsigned integer
// https://github.com/IBM/s390x-abi/releases/tag/v1.6.1
// - z/OS: XL C/C++ Language Reference says: "By default, char behaves like an unsigned char."
// https://www.ibm.com/docs/en/zos/3.1.0?topic=specifiers-character-types
// xtensa:
// Section 2.17.1 "Data Types and Alignment" of Xtensa LX Microprocessor Overview handbook
// says "`char` type is unsigned by default".
// https://loboris.eu/ESP32/Xtensa_lx%20Overview%20handbook.pdf
//
// On the following operating systems, c_char is signed by default, regardless of architecture.
// Darwin (macOS, iOS, etc.):
// Apple targets' c_char is signed by default even on arm
// https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Handle-data-types-and-data-alignment-properly
// Windows:
// Windows MSVC C++ Language Reference says "Microsoft-specific: Variables of type char
// are promoted to int as if from type signed char by default, unless the /J compilation
// option is used."
// https://learn.microsoft.com/en-us/cpp/cpp/fundamental-types-cpp?view=msvc-170#character-types
// L4Re:
// The kernel builds with -funsigned-char on all targets (but useserspace follows the
// architecture defaults). As we only have a target for userspace apps so there are no
// special cases for L4Re below.
// https://github.com/rust-lang/rust/pull/132975#issuecomment-2484645240
if #[cfg(all(
not(windows),
not(target_vendor = "apple"),
any(
target_arch = "aarch64",
target_arch = "arm",
target_arch = "csky",
target_arch = "hexagon",
target_arch = "msp430",
target_arch = "powerpc",
target_arch = "powerpc64",
target_arch = "riscv32",
target_arch = "riscv64",
target_arch = "s390x",
target_arch = "xtensa",
)
))] {
pub(super) type c_char = u8;
} else {
// On every other target, c_char is signed.
pub(super) type c_char = i8;
}
}
}

mod c_int_definition {
cfg_if! {
if #[cfg(any(target_arch = "avr", target_arch = "msp430"))] {
pub(super) type c_int = i16;
pub(super) type c_uint = u16;
} else {
pub(super) type c_int = i32;
pub(super) type c_uint = u32;
}
}
}

mod c_long_definition {
cfg_if! {
if #[cfg(all(target_pointer_width = "64", not(windows)))] {
pub(super) type c_long = i64;
pub(super) type c_ulong = u64;
} else {
// The minimal size of `long` in the C standard is 32 bits
pub(super) type c_long = i32;
pub(super) type c_ulong = u32;
}
}
}
pub use self::primitives::{c_ptrdiff_t, c_size_t, c_ssize_t};

// N.B., for LLVM to recognize the void pointer type and by extension
// functions like malloc(), we need to have it represented as i8* in
Expand Down
174 changes: 174 additions & 0 deletions library/core/src/ffi/primitives.rs
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Original file line number Diff line number Diff line change
@@ -0,0 +1,174 @@
//! Defines primitive types that match C's type definitions for FFI compatibility.
//!
//! This module is intentionally standalone to facilitate parsing when retrieving
//! core C types.

macro_rules! type_alias {
{
$Docfile:tt, $Alias:ident = $Real:ty;
$( $Cfg:tt )*
} => {
#[doc = include_str!($Docfile)]
$( $Cfg )*
#[stable(feature = "core_ffi_c", since = "1.64.0")]
pub type $Alias = $Real;
}
}

type_alias! { "c_char.md", c_char = c_char_definition::c_char; #[doc(cfg(all()))] }

type_alias! { "c_schar.md", c_schar = i8; }
type_alias! { "c_uchar.md", c_uchar = u8; }
type_alias! { "c_short.md", c_short = i16; }
type_alias! { "c_ushort.md", c_ushort = u16; }

type_alias! { "c_int.md", c_int = c_int_definition::c_int; #[doc(cfg(all()))] }
type_alias! { "c_uint.md", c_uint = c_int_definition::c_uint; #[doc(cfg(all()))] }

type_alias! { "c_long.md", c_long = c_long_definition::c_long; #[doc(cfg(all()))] }
type_alias! { "c_ulong.md", c_ulong = c_long_definition::c_ulong; #[doc(cfg(all()))] }

type_alias! { "c_longlong.md", c_longlong = i64; }
type_alias! { "c_ulonglong.md", c_ulonglong = u64; }

type_alias! { "c_float.md", c_float = f32; }
type_alias! { "c_double.md", c_double = f64; }

mod c_char_definition {
cfg_if! {
// These are the targets on which c_char is unsigned. Usually the
// signedness is the same for all target_os values on a given architecture
// but there are some exceptions (see isSignedCharDefault() in clang).
//
// aarch64:
// Section 10 "Arm C and C++ language mappings" in Procedure Call Standard for the Arm®
// 64-bit Architecture (AArch64) says C/C++ char is unsigned byte.
// https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs64/aapcs64.rst#arm-c-and-c-language-mappings
// arm:
// Section 8 "Arm C and C++ Language Mappings" in Procedure Call Standard for the Arm®
// Architecture says C/C++ char is unsigned byte.
// https://github.com/ARM-software/abi-aa/blob/2024Q3/aapcs32/aapcs32.rst#arm-c-and-c-language-mappings
// csky:
// Section 2.1.2 "Primary Data Type" in C-SKY V2 CPU Applications Binary Interface
// Standards Manual says ANSI C char is unsigned byte.
// https://github.com/c-sky/csky-doc/blob/9f7121f7d40970ba5cc0f15716da033db2bb9d07/C-SKY_V2_CPU_Applications_Binary_Interface_Standards_Manual.pdf
// Note: this doesn't seem to match Clang's default (https://github.com/rust-lang/rust/issues/129945).
// hexagon:
// Section 3.1 "Basic data type" in Qualcomm Hexagon™ Application
// Binary Interface User Guide says "By default, the `char` data type is unsigned."
// https://docs.qualcomm.com/bundle/publicresource/80-N2040-23_REV_K_Qualcomm_Hexagon_Application_Binary_Interface_User_Guide.pdf
// msp430:
// Section 2.1 "Basic Types" in MSP430 Embedded Application Binary
// Interface says "The char type is unsigned by default".
// https://www.ti.com/lit/an/slaa534a/slaa534a.pdf
// powerpc/powerpc64:
// - PPC32 SysV: "Table 3-1 Scalar Types" in System V Application Binary Interface PowerPC
// Processor Supplement says ANSI C char is unsigned byte
// https://refspecs.linuxfoundation.org/elf/elfspec_ppc.pdf
// - PPC64 ELFv1: Section 3.1.4 "Fundamental Types" in 64-bit PowerPC ELF Application
// Binary Interface Supplement 1.9 says ANSI C is unsigned byte
// https://refspecs.linuxfoundation.org/ELF/ppc64/PPC-elf64abi.html#FUND-TYPE
// - PPC64 ELFv2: Section 2.1.2.2 "Fundamental Types" in 64-Bit ELF V2 ABI Specification
// says char is unsigned byte
// https://openpowerfoundation.org/specifications/64bitelfabi/
// - AIX: XL C for AIX Language Reference says "By default, char behaves like an unsigned char."
// https://www.ibm.com/docs/en/xl-c-aix/13.1.3?topic=specifiers-character-types
// riscv32/riscv64:
// C/C++ type representations section in RISC-V Calling Conventions
// page in RISC-V ELF psABI Document says "char is unsigned."
// https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/draft-20240829-13bfa9f54634cb60d86b9b333e109f077805b4b3/riscv-cc.adoc#cc-type-representations
// s390x:
// - ELF: "Table 1.1.: Scalar types" in ELF Application Binary Interface s390x Supplement
// Version 1.6.1 categorize ISO C char in unsigned integer
// https://github.com/IBM/s390x-abi/releases/tag/v1.6.1
// - z/OS: XL C/C++ Language Reference says: "By default, char behaves like an unsigned char."
// https://www.ibm.com/docs/en/zos/3.1.0?topic=specifiers-character-types
// xtensa:
// Section 2.17.1 "Data Types and Alignment" of Xtensa LX Microprocessor Overview handbook
// says "`char` type is unsigned by default".
// https://loboris.eu/ESP32/Xtensa_lx%20Overview%20handbook.pdf
//
// On the following operating systems, c_char is signed by default, regardless of architecture.
// Darwin (macOS, iOS, etc.):
// Apple targets' c_char is signed by default even on arm
// https://developer.apple.com/documentation/xcode/writing-arm64-code-for-apple-platforms#Handle-data-types-and-data-alignment-properly
// Windows:
// Windows MSVC C++ Language Reference says "Microsoft-specific: Variables of type char
// are promoted to int as if from type signed char by default, unless the /J compilation
// option is used."
// https://learn.microsoft.com/en-us/cpp/cpp/fundamental-types-cpp?view=msvc-170#character-types
// L4Re:
// The kernel builds with -funsigned-char on all targets (but useserspace follows the
// architecture defaults). As we only have a target for userspace apps so there are no
// special cases for L4Re below.
// https://github.com/rust-lang/rust/pull/132975#issuecomment-2484645240
if #[cfg(all(
not(windows),
not(target_vendor = "apple"),
any(
target_arch = "aarch64",
target_arch = "arm",
target_arch = "csky",
target_arch = "hexagon",
target_arch = "msp430",
target_arch = "powerpc",
target_arch = "powerpc64",
target_arch = "riscv32",
target_arch = "riscv64",
target_arch = "s390x",
target_arch = "xtensa",
)
))] {
pub(super) type c_char = u8;
} else {
// On every other target, c_char is signed.
pub(super) type c_char = i8;
}
}
}

mod c_long_definition {
cfg_if! {
if #[cfg(all(target_pointer_width = "64", not(windows)))] {
pub(super) type c_long = i64;
pub(super) type c_ulong = u64;
} else {
// The minimal size of `long` in the C standard is 32 bits
pub(super) type c_long = i32;
pub(super) type c_ulong = u32;
}
}
}

/// Equivalent to C's `size_t` type, from `stddef.h` (or `cstddef` for C++).
///
/// This type is currently always [`usize`], however in the future there may be
/// platforms where this is not the case.
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_size_t = usize;

/// Equivalent to C's `ptrdiff_t` type, from `stddef.h` (or `cstddef` for C++).
///
/// This type is currently always [`isize`], however in the future there may be
/// platforms where this is not the case.
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_ptrdiff_t = isize;

/// Equivalent to C's `ssize_t` (on POSIX) or `SSIZE_T` (on Windows) type.
///
/// This type is currently always [`isize`], however in the future there may be
/// platforms where this is not the case.
#[unstable(feature = "c_size_t", issue = "88345")]
pub type c_ssize_t = isize;

mod c_int_definition {
cfg_if! {
if #[cfg(any(target_arch = "avr", target_arch = "msp430"))] {
pub(super) type c_int = i16;
pub(super) type c_uint = u16;
} else {
pub(super) type c_int = i32;
pub(super) type c_uint = u32;
}
}
}
3 changes: 2 additions & 1 deletion src/tools/tidy/src/pal.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -48,8 +48,9 @@ const EXCEPTION_PATHS: &[&str] = &[
// we must use `#[cfg(windows)]` to conditionally compile the
// correct `VaList` structure for windows.
"library/core/src/ffi/va_list.rs",
// We placed a linkage against Windows libraries here
// core::ffi contains platform-specific type and linkage configuration
"library/core/src/ffi/mod.rs",
"library/core/src/ffi/primitives.rs",
"library/std/src/sys", // Platform-specific code for std lives here.
"library/std/src/os", // Platform-specific public interfaces
// Temporary `std` exceptions
Expand Down
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