[PATCH] D68720: Support -fstack-clash-protection for x86

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:423
+                               AbsOffset - CurrentAbsOffset + PageSize);
+        if (FreeProbeIterator != MBB.end()) {
+          NumFrameFreeProbe++;
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Each probe has to have an offset of at most PageSize bytes from the previous probe.  If each probe is exactly PageSize bytes away from the previous probe, that's fine.  But it looks like you don't enforce the distance between free probes correctly?


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Comment at: llvm/lib/Target/X86/X86FrameLowering.cpp:481
+                    [](MachineOperand &MO) { return MO.isFI(); })) {
+      break; // effect on stack pointer not modelled, stopping
+    }
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There are instructions that don't refer to any FI, but are still relevant.  For example, calls.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D68720/new/

https://reviews.llvm.org/D68720