| //===-- Classes to capture properites of linux applications -----*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_LIBC_CONFIG_LINUX_APP_H |
| #define LLVM_LIBC_CONFIG_LINUX_APP_H |
| |
| #include "src/__support/architectures.h" |
| |
| #include <stdint.h> |
| |
| namespace __llvm_libc { |
| |
| // Data structure to capture properties of the linux/ELF TLS image. |
| struct TLSImage { |
| // The load address of the TLS. |
| uintptr_t address; |
| |
| // The byte size of the TLS image consisting of both initialized and |
| // uninitialized memory. In ELF executables, it is size of .tdata + size of |
| // .tbss. Put in another way, it is the memsz field of the PT_TLS header. |
| uintptr_t size; |
| |
| // The byte size of initialized memory in the TLS image. In ELF exectubles, |
| // this is the size of .tdata. Put in another way, it is the filesz of the |
| // PT_TLS header. |
| uintptr_t init_size; |
| |
| // The alignment of the TLS layout. It assumed that the alignment |
| // value is a power of 2. |
| uintptr_t align; |
| }; |
| |
| #if defined(LLVM_LIBC_ARCH_X86_64) || defined(LLVM_LIBC_ARCH_AARCH64) |
| // At the language level, argc is an int. But we use uint64_t as the x86_64 |
| // ABI specifies it as an 8 byte value. Likewise, in the ARM64 ABI, arguments |
| // are usually passed in registers. x0 is a doubleword register, so this is |
| // 64 bit for aarch64 as well. |
| typedef uint64_t ArgcType; |
| |
| // At the language level, argv is a char** value. However, we use uint64_t as |
| // ABIs specify the argv vector be an |argc| long array of 8-byte values. |
| typedef uint64_t ArgVEntryType; |
| #else |
| #error "argc and argv types are not defined for the target platform." |
| #endif |
| |
| struct Args { |
| ArgcType argc; |
| |
| // A flexible length array would be more suitable here, but C++ doesn't have |
| // flexible arrays: P1039 proposes to fix this. So, for now we just fake it. |
| // Even if argc is zero, "argv[argc] shall be a null pointer" |
| // (ISO C 5.1.2.2.1) so one is fine. Also, length of 1 is not really wrong as |
| // |argc| is guaranteed to be atleast 1, and there is an 8-byte null entry at |
| // the end of the argv array. |
| ArgVEntryType argv[1]; |
| }; |
| |
| // Data structure which captures properties of a linux application. |
| struct AppProperties { |
| // Page size used for the application. |
| uintptr_t pageSize; |
| |
| Args *args; |
| |
| // The properties of an application's TLS image. |
| TLSImage tls; |
| |
| // Environment data. |
| uint64_t *envPtr; |
| }; |
| |
| extern AppProperties app; |
| |
| // The descriptor of a thread's TLS area. |
| struct TLSDescriptor { |
| // The size of the TLS area. |
| uintptr_t size = 0; |
| |
| // The address of the TLS area. This address can be passed to cleanup |
| // functions like munmap. |
| uintptr_t addr = 0; |
| |
| // The value the thread pointer register should be initialized to. |
| // Note that, dependending the target architecture ABI, it can be the |
| // same as |addr| or something else. |
| uintptr_t tp = 0; |
| |
| constexpr TLSDescriptor() = default; |
| }; |
| |
| // Create and initialize the TLS area for the current thread. Should not |
| // be called before app.tls has been initialized. |
| void init_tls(TLSDescriptor &tls); |
| |
| // Cleanup the TLS area as described in |tls_descriptor|. |
| void cleanup_tls(uintptr_t tls_addr, uintptr_t tls_size); |
| |
| } // namespace __llvm_libc |
| |
| #endif // LLVM_LIBC_CONFIG_LINUX_APP_H |