pcc added inline comments.
================
Comment at: lib/CodeGen/CGExpr.cpp:2494
@@ +2493,3 @@
+ llvm::Value *ValidVtable = nullptr;
+ if (CheckAndAppendValidVtable) {
+ llvm::Value *AllVtables = llvm::MetadataAsValue::get(
----------------
eugenis wrote:
> samsonov wrote:
> > This is really ugly. Why are you not passing it down in DynamicArgs? Is it
> > performance penalty you don't want to pay if the check will not succeed?
> > How large will it be?
> Yes, I want this code to be on the failing side of the check.
> This would cost about the same as the check itself, so I suspect it could
> double the overhead.
>
I would just emit the call unconditionally. We don't care too much about the
performance in non-trapping mode, and if it becomes a problem in practice we
can see if we can have the optimizer move the call into the conditional block
(which I suspect it already knows how to do).
================
Comment at: lib/CodeGen/CodeGenModule.cpp:4053
@@ +4052,3 @@
+
+ if (!CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFIVCall) ||
+ !CodeGenOpts.SanitizeTrap.has(SanitizerKind::CFINVCall) ||
----------------
This conditional doesn't look right. It should be something like
```if (sanitize.has(this) && !sanitizetrap.has(this)) ||
(sanitize.has(that) && !sanitizetrap.has(that)) ||
...
```
But that's sufficiently ugly that I wonder if we should just do this
unconditionally. It shouldn't make a difference to the generated code either
way.
Repository:
rL LLVM
http://reviews.llvm.org/D16823
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