commit 9d096e3cbb5f365d99363d2c377435309f909765
parent 6bd1cb7de768c20fdda94bb18c8ed462204c8590
Author: Henry Wilson <henry@henryandlizzy.uk>
Date: Wed, 24 Dec 2025 21:37:57 +0000
Fix size_t, trial global allocation, disable exceptions
Diffstat:
5 files changed, 58 insertions(+), 23 deletions(-)
diff --git a/Tupfile b/Tupfile
@@ -1,4 +1,4 @@
-CXXFLAGS = -g -Os -fno-asynchronous-unwind-tables -fno-builtin -fno-pic -fno-pie -fno-stack-protector -fdiagnostics-color=always
+CXXFLAGS = -g -Os -fno-exceptions -fno-asynchronous-unwind-tables -fno-builtin -fno-pic -fno-pie -fno-stack-protector -fdiagnostics-color=always
LDFLAGS = --gc-sections
: foreach *.cpp |> clang++ --target=aarch64 $(CXXFLAGS) -c -o %o %f |> obj/%B.aarch64.o {objs-aarch64}
diff --git a/aarch64.s b/aarch64.s
@@ -29,15 +29,15 @@ extern_alias \name
.global exit
extern getdents64
-extern_alias _Z10getdents644fileP14linux_dirent64y
+extern_alias _Z10getdents644fileP14linux_dirent64m
syscall 61
extern read
-extern_alias _Z4read4filePcy
+extern_alias _Z4read4filePcm
syscall 63
extern write
-extern_alias _Z5write4filePKcy
+extern_alias _Z5write4filePKcm
extern_alias _Z5write4file4spanIKcE
syscall 64
@@ -61,6 +61,10 @@ extern nanosleep
extern_alias _Z9nanosleepRK8timespecPS_
syscall 101
+extern munmap
+extern_alias _Z6munmapPvm
+syscall 215
+
extern mmap
extern_alias _Z4mmapPvmmm4filem
syscall 222
diff --git a/linux.hpp b/linux.hpp
@@ -1,7 +1,7 @@
#pragma once
-using uint64_t = unsigned long long;
-using int64_t = signed long long;
+using uint64_t = unsigned long;
+using int64_t = signed long;
using uint32_t = unsigned int;
using int32_t = signed int;
using uint16_t = unsigned short;
@@ -123,26 +123,26 @@ private:
};
[[noreturn]]
-extern void exit(int error_code);
+extern void exit(int error_code) noexcept;
-extern syscall_result<size_t> read(file fd, char data[], size_t count);
-extern syscall_result<size_t> read(file fd, span<char> data);
-inline syscall_result<size_t> read(file fd, char* begin, char* end)
+extern syscall_result<size_t> read(file fd, char data[], size_t count) noexcept;
+extern syscall_result<size_t> read(file fd, span<char> data) noexcept;
+inline syscall_result<size_t> read(file fd, char* begin, char* end) noexcept
{
return read(fd, begin, end - begin);
}
-extern syscall_result<size_t> write(file fd, char const data[], size_t count);
-extern syscall_result<size_t> write(file fd, span<char const> data);
-extern syscall_result<size_t> write(file fd, span<span<char const> const> data);
-inline syscall_result<size_t> write(file fd, char const* begin, char const* end)
+extern syscall_result<size_t> write(file fd, char const data[], size_t count) noexcept;
+extern syscall_result<size_t> write(file fd, span<char const> data) noexcept;
+extern syscall_result<size_t> write(file fd, span<span<char const> const> data) noexcept;
+inline syscall_result<size_t> write(file fd, char const* begin, char const* end) noexcept
{
return write(fd, begin, end - begin);
}
-extern syscall_result<file> openat(file fd, c_str name, int flags, int mode);
+extern syscall_result<file> openat(file fd, c_str name, int flags, int mode) noexcept;
-extern syscall_result<void> close(file fd);
+extern syscall_result<void> close(file fd) noexcept;
struct linux_dirent64 {
ino64_t d_ino; /* 64-bit inode number */
@@ -151,16 +151,17 @@ struct linux_dirent64 {
unsigned char d_type; /* File type */
char d_name[]; /* Filename (null-terminated) */
};
-extern syscall_result<size_t> getdents64(file dir, linux_dirent64 dirp[], size_t count);
+extern syscall_result<size_t> getdents64(file dir, linux_dirent64 dirp[], size_t count) noexcept;
-extern syscall_result<void*> mmap(void* addr, unsigned long len, unsigned long prot, unsigned long flags, file fd, unsigned long off);
+extern syscall_result<void*> mmap(void* addr, size_t len, unsigned long prot, unsigned long flags, file fd, size_t off) noexcept;
+extern syscall_result<void> munmap(void* addr, size_t len) noexcept;
struct timespec {
time_t tv_sec; /* Seconds */
uint32_t tv_nsec; /* Nanoseconds [0, 999'999'999] */
};
-extern syscall_result<void> nanosleep(const timespec &duration, timespec */*_Nullable*/ rem);
+extern syscall_result<void> nanosleep(const timespec &duration, timespec */*_Nullable*/ rem) noexcept;
enum class rename_flags : unsigned int
{
@@ -169,4 +170,4 @@ enum class rename_flags : unsigned int
WHITEOUT = 0b100,
};
-extern syscall_result<void> renameat2(file olddir, c_str oldpath, file newdir, c_str newpath, rename_flags flags);
+extern syscall_result<void> renameat2(file olddir, c_str oldpath, file newdir, c_str newpath, rename_flags flags) noexcept;
diff --git a/new.cpp b/new.cpp
@@ -0,0 +1,26 @@
+#include "linux.hpp"
+
+namespace std {
+
+struct nothrow_t {};
+constexpr nothrow_t nothrow;
+
+}
+
+void* operator new(size_t size, std::nothrow_t const&) noexcept
+{
+ return *mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_ANONYMOUS | MAP_PRIVATE, {}, 0);
+}
+
+void operator delete(void* p, size_t size) noexcept
+{
+ *munmap(p, size);
+}
+
+int main()
+{
+ auto p = new (std::nothrow) int{5};
+ int x = *p;
+ delete p;
+ return x;
+}
diff --git a/x86_64.s b/x86_64.s
@@ -45,11 +45,11 @@ syscall6:
ret
extern read
-extern_alias _Z4read4filePcy
+extern_alias _Z4read4filePcm
_syscall 0 syscall3
extern write
-extern_alias _Z5write4filePKcy
+extern_alias _Z5write4filePKcm
extern_alias _Z5write4file4spanIKcE
_syscall 1 syscall3
@@ -61,6 +61,10 @@ extern mmap
extern_alias _Z4mmapPvmmm4filem
_syscall 9 syscall6
+extern munmap
+extern_alias _Z6munmapPvm
+_syscall 11 syscall3
+
extern writev
extern_alias _Z5write4file4spanIKS0_IKcEE
_syscall 20 syscall3
@@ -74,7 +78,7 @@ extern_alias _Z4exiti
_syscall 60 syscall3
extern getdents64
-extern_alias _Z10getdents644fileP14linux_dirent64y
+extern_alias _Z10getdents644fileP14linux_dirent64m
_syscall 217 syscall3
extern openat
