[PATCH] D79910: [x86][seses] Add clang flag; Use lvi-cfi with seses

[Craig Topper via Phabricator via cfe-commits]

craig.topper added inline comments.


================
Comment at: clang/lib/Driver/ToolChains/Arch/X86.cpp:200
+    if (!Args.hasArg(options::OPT_mno_lvi_cfi)) {
+      Features.push_back("+lvi-cfi");
+      LVIOpt = options::OPT_mlvi_cfi;
----------------
sconstab wrote:
> zbrid wrote:
> > sconstab wrote:
> > > Would it be better to add `FeatureLVIControlFlowIntegrity` as a dependency for `FeatureSpeculativeExecutionSideEffectSuppression` in `llvm/lib/Target/X86/X86.td`?
> > Thanks for the tip! Yeah, I will update to do that, but it looks like that only ensures an error will be thrown if they aren't used together rather than ensuring one is enabled when the other is enabled. Am I misunderstanding?
> I'm not certain about this either. @craig.topper opinion?
Making them dependent in X86.td will make +sese imply +lvi-cfi and make -lvi-cfi imply -sese. So sese can never be enabled without lvi-cfi also enabled.


Repository:
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  https://reviews.llvm.org/D79910/new/

https://reviews.llvm.org/D79910