[PATCH] D100919: [AArch64] Support customizing stack protector guard

[Nick Desaulniers via Phabricator via cfe-commits]

nickdesaulniers added a comment.

In D100919#2750125 <https://reviews.llvm.org/D100919#2750125>, @dmgreen wrote:

> It's worth adding -verify-machineinstrs to the tests, to check the code passes the internal checks.

Done.



================
Comment at: llvm/lib/Target/AArch64/AArch64InstrInfo.cpp:1917
+            .addDef(Reg)
+            .addImm(Options.StackProtectorGuardOffset >> 3);
+      else
----------------
dmgreen wrote:
> What is StackProtectorGuardOffset, and could is be out of range for the load? That is something that verify-machineinstrs won't currently check for.
It's passed from the front end; it's an offset added to the pointer load.  The Linux kernel uses a value in 1100-1200 range. GCC will let you use whatever large value and keep appending adds for constants greater than 32200: https://godbolt.org/z/1xhbEPbKG, but YAGNI.


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https://reviews.llvm.org/D100919