[PATCH] D84913: [libFuzzer] Enable for SystemZ

[Kostya Serebryany via Phabricator via llvm-commits]

kcc added inline comments.


================
Comment at: compiler-rt/lib/fuzzer/FuzzerTracePC.h:198
+    if (LargeType Bundle = *reinterpret_cast<const LargeType *>(P)) {
+#if __BYTE_ORDER == __BIG_ENDIAN
+      Bundle = Bswap(Bundle);
----------------
iii wrote:
> kcc wrote:
> > please avoid #ifdefs inside functions. 
> > If there is some logic that needs to depend on the platform, it needs to reside in a separate dedicated function. 
> > 
> > FuzzerBuiltins.h is probably the place for such a function. 
> > 
> > Also, what about 
> >        #include <endian.h>
> >        uint64_t htole64(uint64_t host_64bits);
> > is that portable? 
> > 
> I think this might not work as expected on 32-bit systems. I'll add a separate function.
No strong preference. 
I've just checked, on Linux x86_64: it inlines and works great. 
Dunno if it will have portability issues. 

```
% cat x.cc 
 #include <endian.h>
#include <stdint.h>

uint64_t foo(uint64_t x) {
  return htole64(x);
}
% clang -O2 -S -o - x.cc -m32
        movl    4(%esp), %eax
        movl    8(%esp), %edx
        retl

% clang -O2 -S -o - x.cc 

        movq    %rdi, %rax
        retq
```

`htobe64` also looks nice, it translates into one `bswapq` on 64-bit and two `bswapl` on 32-bit, 
i.e. in your case this is what `htole64` will do. 


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D84913/new/

https://reviews.llvm.org/D84913