Re: [PATCH] Mips: Resolve build issues for the n32 ABI

[Xi Ruoyao <xry111@xry111.site>]

On Fri, 2022-07-01 at 12:40 +0000, Dimitrije Milosevic wrote:
> Building the ASAN for the n32 MIPS ABI currently fails, due to a few reasons:
> - defined(__mips64), which is set solely based on the architecture type (32-bit/64-bit), 
> was still used in some places. Therefore, defined(__mips64) is swapped with SANITIZER_MIPS64, 
> which takes the ABI into account as well - defined(__mips64) && 
> _MIPS_SIM == ABI64.
> - The n32 ABI still uses 64-bit *Linux* system calls, even though the word size is 32 bits.
> - After the transition to canonical system calls 
> (https://reviews.llvm.org/D124212), the n32 ABI still didn't use them,
> even though they are supported,
> as per https://github.com/torvalds/linux/blob/master/arch/mips/kernel/syscalls/syscall_n32.tbl.
> 
> See https://reviews.llvm.org/D127098.
> 
>     libsanitizer/ChangeLog:
>     
>             * sanitizer_common/sanitizer_linux.cpp (defined): Resolve
>             ASAN build issues for the Mips n32 ABI.
>             * sanitizer_common/sanitizer_platform.h (defined): Likewise.

LGTM (with the ChangeLog format fixed), but I think you need to commit
this into LLVM repository first.  And in the commit message you should
say something like "cherry-pick 0011aabb... from upstream".  Then we
still require the approve from a maintainer.

> ---
> 
>  libsanitizer/sanitizer_common/sanitizer_linux.cpp  | 17 ++++++++++-------
>  libsanitizer/sanitizer_common/sanitizer_platform.h |  2 +-
>  2 files changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/libsanitizer/sanitizer_common/sanitizer_linux.cpp b/libsanitizer/sanitizer_common/sanitizer_linux.cpp
> index e2c32d679ad..5ba033492e7 100644
> --- a/libsanitizer/sanitizer_common/sanitizer_linux.cpp
> +++ b/libsanitizer/sanitizer_common/sanitizer_linux.cpp
> @@ -34,7 +34,7 @@
>  // format. Struct kernel_stat is defined as 'struct stat' in asm/stat.h. To
>  // access stat from asm/stat.h, without conflicting with definition in
>  // sys/stat.h, we use this trick.
> -#if defined(__mips64)
> +#if SANITIZER_MIPS64
>  #include <asm/unistd.h>
>  #include <sys/types.h>
>  #define stat kernel_stat
> @@ -124,8 +124,9 @@ const int FUTEX_WAKE_PRIVATE = FUTEX_WAKE | FUTEX_PRIVATE_FLAG;
>  // Are we using 32-bit or 64-bit Linux syscalls?
>  // x32 (which defines __x86_64__) has SANITIZER_WORDSIZE == 32
>  // but it still needs to use 64-bit syscalls.
> -#if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) ||       \
> -                        SANITIZER_WORDSIZE == 64)
> +#if SANITIZER_LINUX && (defined(__x86_64__) || defined(__powerpc64__) || \
> +                        SANITIZER_WORDSIZE == 64 ||                      \
> +                        (defined(__mips__) && _MIPS_SIM == _ABIN32))
>  # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 1
>  #else
>  # define SANITIZER_LINUX_USES_64BIT_SYSCALLS 0
> @@ -289,7 +290,7 @@ static void stat64_to_stat(struct stat64 *in, struct stat *out) {
>  }
>  #endif
>  
> -#if defined(__mips64)
> +#if SANITIZER_MIPS64
>  // Undefine compatibility macros from <sys/stat.h>
>  // so that they would not clash with the kernel_stat
>  // st_[a|m|c]time fields
> @@ -343,7 +344,8 @@ uptr internal_stat(const char *path, void *buf) {
>  #if SANITIZER_FREEBSD
>    return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf, 0);
>  #    elif SANITIZER_LINUX
> -#      if SANITIZER_WORDSIZE == 64 || SANITIZER_X32
> +#      if SANITIZER_WORDSIZE == 64 || SANITIZER_X32 || \
> +          (defined(__mips__) && _MIPS_SIM == _ABIN32)
>    return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
>                            0);
>  #      else
> @@ -366,7 +368,8 @@ uptr internal_lstat(const char *path, void *buf) {
>    return internal_syscall(SYSCALL(fstatat), AT_FDCWD, (uptr)path, (uptr)buf,
>                            AT_SYMLINK_NOFOLLOW);
>  #    elif SANITIZER_LINUX
> -#      if defined(_LP64) || SANITIZER_X32
> +#      if defined(_LP64) || SANITIZER_X32 ||         \
> +          (defined(__mips__) && _MIPS_SIM == _ABIN32)
>    return internal_syscall(SYSCALL(newfstatat), AT_FDCWD, (uptr)path, (uptr)buf,
>                            AT_SYMLINK_NOFOLLOW);
>  #      else
> @@ -1053,7 +1056,7 @@ uptr GetMaxVirtualAddress() {
>    return (1ULL << (MostSignificantSetBitIndex(GET_CURRENT_FRAME()) + 1)) - 1;
>  #elif SANITIZER_RISCV64
>    return (1ULL << 38) - 1;
> -# elif defined(__mips64)
> +# elif SANITIZER_MIPS64
>    return (1ULL << 40) - 1;  // 0x000000ffffffffffUL;
>  # elif defined(__s390x__)
>    return (1ULL << 53) - 1;  // 0x001fffffffffffffUL;
> diff --git a/libsanitizer/sanitizer_common/sanitizer_platform.h b/libsanitizer/sanitizer_common/sanitizer_platform.h
> index 8fe0d831431..8bd9a327623 100644
> --- a/libsanitizer/sanitizer_common/sanitizer_platform.h
> +++ b/libsanitizer/sanitizer_common/sanitizer_platform.h
> @@ -159,7 +159,7 @@
>  
>  #if defined(__mips__)
>  #  define SANITIZER_MIPS 1
> -#  if defined(__mips64)
> +#  if defined(__mips64) && _MIPS_SIM == _ABI64
>  #    define SANITIZER_MIPS32 0
>  #    define SANITIZER_MIPS64 1
>  #  else
> 
> ---

-- 
Xi Ruoyao <xry111@xry111.site>
School of Aerospace Science and Technology, Xidian University