mirror of
https://github.com/apple/swift.git
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84a1ffcb33
This replaces a number of `#include`-s like this:
```
#include "../../../stdlib/public/SwiftShims/Visibility.h"
```
with this:
```
#include "swift/shims/Visibility.h"
```
This is needed to allow SwiftCompilerSources to use C++ headers which include SwiftShims headers. Currently trying to do that results in errors:
```
swift/swift/include/swift/Demangling/../../../stdlib/public/SwiftShims/module.modulemap:1:8: error: redefinition of module 'SwiftShims'
module SwiftShims {
^
Builds.noindex/swift/swift/bootstrapping0/lib/swift/shims/module.modulemap:1:8: note: previously defined here
module SwiftShims {
^
```
This happens because the headers in both the source dir and the build dir refer to SwiftShims headers by relative path, and both the source root and the build root contain SwiftShims headers (which are equivalent, but since they are located in different dirs, Clang treats them as different modules).
228 lines
10 KiB
C++
228 lines
10 KiB
C++
//===--- System.h - Swift ABI system-specific constants ---------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// Here are some fun facts about the target platforms we support!
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_STDLIB_SHIMS_ABI_SYSTEM_H
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#define SWIFT_STDLIB_SHIMS_ABI_SYSTEM_H
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// In general, these macros are expected to expand to host-independent
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// integer constant expressions. This allows the same data to feed
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// both the compiler and runtime implementation.
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/******************************* Default Rules ********************************/
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/// The least valid pointer value for an actual pointer (as opposed to
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/// Objective-C pointers, which may be tagged pointers and are covered
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/// separately). Values up to this are "extra inhabitants" of the
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/// pointer representation, and payloaded enum types can take
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/// advantage of that as they see fit.
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///
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/// By default, we assume that there's at least an unmapped page at
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/// the bottom of the address space. 4K is a reasonably likely page
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/// size.
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///
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/// The minimum possible value for this macro is 1; we always assume
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/// that the null representation is available.
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#define SWIFT_ABI_DEFAULT_LEAST_VALID_POINTER 4096
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/// The bitmask of spare bits in a function pointer.
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#define SWIFT_ABI_DEFAULT_FUNCTION_SPARE_BITS_MASK 0
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/// The bitmask of spare bits in a Swift heap object pointer. A Swift
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/// heap object allocation will never set any of these bits.
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#define SWIFT_ABI_DEFAULT_SWIFT_SPARE_BITS_MASK 0
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/// The bitmask of reserved bits in an Objective-C object pointer.
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/// By default we assume the ObjC runtime doesn't use tagged pointers.
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#define SWIFT_ABI_DEFAULT_OBJC_RESERVED_BITS_MASK 0
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/// The number of low bits in an Objective-C object pointer that
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/// are reserved by the Objective-C runtime.
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#define SWIFT_ABI_DEFAULT_OBJC_NUM_RESERVED_LOW_BITS 0
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/// The ObjC runtime will not use pointer values for which
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/// ``pointer & SWIFT_ABI_XXX_OBJC_RESERVED_BITS_MASK == 0 &&
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/// pointer & SWIFT_ABI_XXX_SWIFT_SPARE_BITS_MASK != 0``.
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// Weak references use a marker to tell when they are controlled by
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// the ObjC runtime and when they are controlled by the Swift runtime.
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// Non-ObjC platforms don't use this marker.
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#define SWIFT_ABI_DEFAULT_OBJC_WEAK_REFERENCE_MARKER_MASK 0
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#define SWIFT_ABI_DEFAULT_OBJC_WEAK_REFERENCE_MARKER_VALUE 0
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// BridgeObject uses this bit to indicate a tagged value.
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#define SWIFT_ABI_DEFAULT_BRIDGEOBJECT_TAG_32 0U
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#define SWIFT_ABI_DEFAULT_BRIDGEOBJECT_TAG_64 0x8000000000000000ULL
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// Only the bottom 56 bits are used, and heap objects are eight-byte-aligned.
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#define SWIFT_ABI_DEFAULT_64BIT_SPARE_BITS_MASK 0xFF00000000000007ULL
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// Poison sentinel value recognized by LLDB as a former reference to a
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// potentially deinitialized object. It uses no spare bits and cannot point to
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// readable memory.
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//
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// This is not ABI per-se but does stay in-sync with LLDB. If it becomes
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// out-of-sync, then users won't see a friendly diagnostic when inspecting
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// references past their lifetime.
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#define SWIFT_ABI_DEFAULT_REFERENCE_POISON_DEBUG_VALUE_32 0x00000440U
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#define SWIFT_ABI_DEFAULT_REFERENCE_POISON_DEBUG_VALUE_64 0x0000000000000440ULL
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/*********************************** i386 *************************************/
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// Heap objects are pointer-aligned, so the low two bits are unused.
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#define SWIFT_ABI_I386_SWIFT_SPARE_BITS_MASK 0x00000003U
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// ObjC weak reference discriminator is the LSB.
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#define SWIFT_ABI_I386_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_DEFAULT_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_DEFAULT_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_I386_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_DEFAULT_OBJC_NUM_RESERVED_LOW_BITS)
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// BridgeObject uses this bit to indicate whether it holds an ObjC object or
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// not.
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#define SWIFT_ABI_I386_IS_OBJC_BIT 0x00000002U
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/*********************************** arm **************************************/
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// Heap objects are pointer-aligned, so the low two bits are unused.
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#define SWIFT_ABI_ARM_SWIFT_SPARE_BITS_MASK 0x00000003U
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// ObjC weak reference discriminator is the LSB.
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#define SWIFT_ABI_ARM_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_DEFAULT_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_DEFAULT_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_ARM_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_DEFAULT_OBJC_NUM_RESERVED_LOW_BITS)
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// BridgeObject uses this bit to indicate whether it holds an ObjC object or
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// not.
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#define SWIFT_ABI_ARM_IS_OBJC_BIT 0x00000002U
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/*********************************** x86-64 ***********************************/
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/// Darwin reserves the low 4GB of address space.
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#define SWIFT_ABI_DARWIN_X86_64_LEAST_VALID_POINTER 0x100000000ULL
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// Only the bottom 56 bits are used, and heap objects are eight-byte-aligned.
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// This is conservative: in practice architectural limitations and other
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// compatibility concerns likely constrain the address space to 52 bits.
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#define SWIFT_ABI_X86_64_SWIFT_SPARE_BITS_MASK \
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SWIFT_ABI_DEFAULT_64BIT_SPARE_BITS_MASK
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// Objective-C reserves the low bit for tagged pointers on macOS, but
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// reserves the high bit on simulators.
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#define SWIFT_ABI_X86_64_OBJC_RESERVED_BITS_MASK 0x0000000000000001ULL
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#define SWIFT_ABI_X86_64_OBJC_NUM_RESERVED_LOW_BITS 1
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#define SWIFT_ABI_X86_64_SIMULATOR_OBJC_RESERVED_BITS_MASK 0x8000000000000000ULL
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#define SWIFT_ABI_X86_64_SIMULATOR_OBJC_NUM_RESERVED_LOW_BITS 0
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// BridgeObject uses this bit to indicate whether it holds an ObjC object or
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// not.
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#define SWIFT_ABI_X86_64_IS_OBJC_BIT 0x4000000000000000ULL
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// ObjC weak reference discriminator is the bit reserved for ObjC tagged
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// pointers plus one more low bit.
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#define SWIFT_ABI_X86_64_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_X86_64_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_X86_64_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_X86_64_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_X86_64_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_X86_64_SIMULATOR_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_X86_64_SIMULATOR_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_X86_64_SIMULATOR_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_X86_64_SIMULATOR_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_X86_64_SIMULATOR_OBJC_NUM_RESERVED_LOW_BITS)
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/*********************************** arm64 ************************************/
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/// Darwin reserves the low 4GB of address space.
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#define SWIFT_ABI_DARWIN_ARM64_LEAST_VALID_POINTER 0x100000000ULL
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// Android AArch64 reserves the top byte for pointer tagging since Android 11,
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// so shift the spare bits tag to the second byte and zero the ObjC tag.
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#define SWIFT_ABI_ANDROID_ARM64_SWIFT_SPARE_BITS_MASK 0x00F0000000000007ULL
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#define SWIFT_ABI_ANDROID_ARM64_OBJC_RESERVED_BITS_MASK 0x0000000000000000ULL
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#if defined(__ANDROID__) && defined(__aarch64__)
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#define SWIFT_ABI_ARM64_SWIFT_SPARE_BITS_MASK SWIFT_ABI_ANDROID_ARM64_SWIFT_SPARE_BITS_MASK
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#else
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// TBI guarantees the top byte of pointers is unused, but ARMv8.5-A
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// claims the bottom four bits of that for memory tagging.
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// Heap objects are eight-byte aligned.
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#define SWIFT_ABI_ARM64_SWIFT_SPARE_BITS_MASK 0xF000000000000007ULL
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#endif
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// Objective-C reserves just the high bit for tagged pointers.
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#define SWIFT_ABI_ARM64_OBJC_RESERVED_BITS_MASK 0x8000000000000000ULL
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#define SWIFT_ABI_ARM64_OBJC_NUM_RESERVED_LOW_BITS 0
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// BridgeObject uses this bit to indicate whether it holds an ObjC object or
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// not.
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#define SWIFT_ABI_ARM64_IS_OBJC_BIT 0x4000000000000000ULL
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// ObjC weak reference discriminator is the high bit
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// reserved for ObjC tagged pointers plus the LSB.
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#define SWIFT_ABI_ARM64_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_ARM64_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_ARM64_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_ARM64_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_ARM64_OBJC_NUM_RESERVED_LOW_BITS)
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/*********************************** powerpc ********************************/
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// Heap objects are pointer-aligned, so the low two bits are unused.
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#define SWIFT_ABI_POWERPC_SWIFT_SPARE_BITS_MASK 0x00000003U
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/*********************************** powerpc64 ********************************/
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// Heap objects are pointer-aligned, so the low three bits are unused.
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#define SWIFT_ABI_POWERPC64_SWIFT_SPARE_BITS_MASK \
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SWIFT_ABI_DEFAULT_64BIT_SPARE_BITS_MASK
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/*********************************** s390x ************************************/
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// Top byte of pointers is unused, and heap objects are eight-byte aligned.
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// On s390x it is theoretically possible to have high bit set but in practice
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// it is unlikely.
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#define SWIFT_ABI_S390X_SWIFT_SPARE_BITS_MASK SWIFT_ABI_DEFAULT_64BIT_SPARE_BITS_MASK
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// Objective-C reserves just the high bit for tagged pointers.
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#define SWIFT_ABI_S390X_OBJC_RESERVED_BITS_MASK 0x8000000000000000ULL
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#define SWIFT_ABI_S390X_OBJC_NUM_RESERVED_LOW_BITS 0
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// BridgeObject uses this bit to indicate whether it holds an ObjC object or
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// not.
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#define SWIFT_ABI_S390X_IS_OBJC_BIT 0x4000000000000000ULL
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// ObjC weak reference discriminator is the high bit
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// reserved for ObjC tagged pointers plus the LSB.
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#define SWIFT_ABI_S390X_OBJC_WEAK_REFERENCE_MARKER_MASK \
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(SWIFT_ABI_S390X_OBJC_RESERVED_BITS_MASK | \
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1<<SWIFT_ABI_S390X_OBJC_NUM_RESERVED_LOW_BITS)
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#define SWIFT_ABI_S390X_OBJC_WEAK_REFERENCE_MARKER_VALUE \
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(1<<SWIFT_ABI_S390X_OBJC_NUM_RESERVED_LOW_BITS)
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/*********************************** wasm32 ************************************/
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// WebAssembly doesn't reserve low addresses. But without "extra inhabitants" of
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// the pointer representation, runtime performance and memory footprint are
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// worse. So assume that compiler driver uses wasm-ld and --global-base=1024 to
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// reserve low 1KB.
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#define SWIFT_ABI_WASM32_LEAST_VALID_POINTER 4096
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#endif // SWIFT_STDLIB_SHIMS_ABI_SYSTEM_H
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