Merge pull request #2922 from facebook/x32

x32 compatibility

.github/workflows/dev-short-tests.yml

@@ -37,6 +37,18 @@ jobs:
         APT_PACKAGES="gcc-multilib" make apt-install
         CFLAGS="-m32 -O1 -fstack-protector" make check V=1
 
+  check-x32:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: make check on x32 ABI # https://en.wikipedia.org/wiki/X32_ABI
+      env:
+        CHECK_CONSTRAINED_MEM: true
+      run: |
+        sudo apt update
+        APT_PACKAGES="gcc-multilib" make apt-install
+        CFLAGS="-mx32 -O1 -fstack-protector" make check V=1
+
   gcc-7-libzstd:
     runs-on: ubuntu-latest
     steps:

lib/decompress/huf_decompress.c

@@ -172,8 +172,9 @@ static size_t HUF_DecompressAsmArgs_init(HUF_DecompressAsmArgs* args, void* dst,
 
     BYTE* const oend = (BYTE*)dst + dstSize;
 
-    /* We're assuming x86-64 BMI2 - assure that this is the case. */
+    /* The following condition is false on x32 platform,
-    assert(MEM_isLittleEndian() && !MEM_32bits());
+     * but HUF_asm is not compatible with this ABI */
+    if (!(MEM_isLittleEndian() && !MEM_32bits())) return 1;
 
     /* strict minimum : jump table + 1 byte per stream */
     if (srcSize < 10)