[PATCH] D114194: [SystemZ] Add range checks for PC-relative fixups

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa added inline comments.


================
Comment at: llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp:43
+  auto handlePCRelFixupValue = [&](unsigned W) -> uint64_t {
+    assert(Value % 2 == 0 && "Non-even PC relative offset.");
+    if (!checkFixupInRange(minIntN(W) * 2, maxIntN(W) * 2))
----------------
uweigand wrote:
> Hmm, this scenario could be triggered by wrong assembler input (e.g. something simple like `j .+1`), so I don't think this should result in an assert (internal compiler error).
> 
> GCC/binutils currently seems to simply ignore that case (and round down), which also isn't ideal.
> 
> I think this really should be a user-level error message, not an assert.
Changed this like:


```
   auto handlePCRelFixupValue = [&](unsigned W) -> uint64_t {
-    assert(Value % 2 == 0 && "Non-even PC relative offset.");
+    if (Value % 2 != 0)
+      Ctx.reportError(Fixup.getLoc(), "Non-even PC relative offset.");
     if (!checkFixupInRange(minIntN(W) * 2, maxIntN(W) * 2))
       return 0;
     return (int64_t)Value / 2;
```



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D114194/new/

https://reviews.llvm.org/D114194