[PATCH] D99078: [LLD] Implement /guard:[no]ehcont

[Alvin Wong via Phabricator via llvm-commits]

alvinhochun added inline comments.
Herald added a subscriber: ormris.
Herald added a project: All.


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Comment at: lld/COFF/DriverUtils.cpp:104-111
     else if (arg.equals_lower("nolongjmp"))
-      config->guardCF = GuardCFLevel::NoLongJmp;
-    else if (arg.equals_lower("cf") || arg.equals_lower("longjmp"))
-      config->guardCF = GuardCFLevel::Full;
+      config->guardCF &= ~GuardCFLevel::LongJmp;
+    else if (arg.equals_lower("noehcont"))
+      config->guardCF &= ~GuardCFLevel::EHCont;
+    else if (arg.equals_lower("cf"))
+      config->guardCF = GuardCFLevel::CF;
+    else if (arg.equals_lower("longjmp"))
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This changed the behaviour of `/guard:cf`. Before this change, `/guard:cf` is equivalent to `/guard:cf,longjmp` by default, but after this change one must explicitly pass `/guard:longjmp` to`lld-link for it to generate the guard long jump table.

This also does not match the behaviour of MSVC's link.exe. From my quick testing, `/guard:cf`, `/guard:longjmp` and `/guard:cf,longjmp` all do the same thing for it to enable both CFGuard and the long jump table. Only when you pass `/guard:cf,nolongjmp` is the jump table not present in the final image.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99078/new/

https://reviews.llvm.org/D99078