[PATCH] D61881: Deal with return-twice function such as vfork, setjmp when CET-IBT enabled

[Xiang Zhang via Phabricator via llvm-commits]

xiangzhangllvm marked 2 inline comments as done.
xiangzhangllvm added inline comments.


================
Comment at: lib/Target/X86/X86IndirectBranchTracking.cpp:139
+
+    for (MachineBasicBlock::iterator I = MBB.begin(), E = MBB.end(); I != E;
+         ++I) {
----------------
I find here line 139 maybe problem:
I should change to 

```
for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end();  //because the MBB may update by insert endbr.
```


================
Comment at: lib/Target/X86/X86IndirectBranchTracking.cpp:144
+      if (IsCallReturnTwice(I->getOperand(0)))
+        Changed |= addENDBR(MBB, I);
+    }
----------------
craig.topper wrote:
> What if we passed I++ here and passed MBB.begin() on the other callsites. Could we then avoid two different cases in addENDBR?
Hi Craig, we can not avoid.
because the 2 cases in addENDBR(MBB, I) are different.

one case is insert endbr after I
and another case is insert endbr before I




Repository:
  rL LLVM

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  https://reviews.llvm.org/D61881/new/

https://reviews.llvm.org/D61881