[compiler-rt] [sanitizer_common][test] Fix InternalMmapWithOffset on 32-bit Linux/s… (PR #101011)

[Rainer Orth via llvm-commits]

https://github.com/rorth created https://github.com/llvm/llvm-project/pull/101011

…parc64

```
  SanitizerCommon-Unit :: ./Sanitizer-sparc-Test/SanitizerCommon/InternalMmapWithOffset

```
`FAIL`s on 32-bit Linux/sparc64:
```
projects/compiler-rt/lib/sanitizer_common/tests/./Sanitizer-sparc-Test --gtest_filter=SanitizerCommon.InternalMmapWithOffset
--
compiler-rt/lib/sanitizer_common/tests/sanitizer_libc_test.cpp:335: Failure
Expected equality of these values:
  'A'
    Which is: 'A' (65, 0x41)
  p[0]
    Which is: '\0'
```
It turns out the `pgoffset` arg to `mmap2` is passed incorrectly in this case, unlike the 64-bit test.  The caller, `MapWritableFileToMemory`, passes an `u64` arg, while `mmap2` expects an `off_t`.  This patch casts the arg accordingly.

Tested on `sparc64-unknown-linux-gnu` and `x86_64-pc-linux-gnu`.

>From a8260d9a77240cb7c21a1bb9085927533d2db39a Mon Sep 17 00:00:00 2001
From: Rainer Orth <ro at gcc.gnu.org>
Date: Mon, 29 Jul 2024 15:39:39 +0200
Subject: [PATCH] [sanitizer_common][test] Fix InternalMmapWithOffset on 32-bit
 Linux/sparc64

```
  SanitizerCommon-Unit :: ./Sanitizer-sparc-Test/SanitizerCommon/InternalMmapWithOffset

```
`FAIL`s on 32-bit Linux/sparc64:
```
projects/compiler-rt/lib/sanitizer_common/tests/./Sanitizer-sparc-Test --gtest_filter=SanitizerCommon.InternalMmapWithOffset
--
compiler-rt/lib/sanitizer_common/tests/sanitizer_libc_test.cpp:335: Failure
Expected equality of these values:
  'A'
    Which is: 'A' (65, 0x41)
  p[0]
    Which is: '\0'
```
It turns out the `pgoffset` arg to `mmap2` is passed incorrectly in this
case, unlike the 64-bit test.  The caller, `MapWritableFileToMemory`, passes
an `u64` arg, while `mmap2` expects an `off_t`.  This patch casts the arg
accordingly.

Tested on `sparc64-unknown-linux-gnu` and `x86_64-pc-linux-gnu`.
---
 compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
index 2ea61b1cb424c..2de44197d16c0 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_linux.cpp
@@ -220,7 +220,7 @@ uptr internal_mmap(void *addr, uptr length, int prot, int flags, int fd,
   // mmap2 specifies file offset in 4096-byte units.
   CHECK(IsAligned(offset, 4096));
   return internal_syscall(SYSCALL(mmap2), addr, length, prot, flags, fd,
-                          offset / 4096);
+                          (OFF_T)(offset / 4096));
 #      endif
 }
 #    endif  // !SANITIZER_S390