[PATCH] D15660: [cfi] Cross-DSO CFI diagnostic mode (llvm part)

[Peter Collingbourne via llvm-commits]

pcc added a comment.

It doesn't need to be done now, but I think we should consider moving most of the functionality from this pass to Clang. We could consider introducing an intrinsic that looks like this:

`i1 @llvm.bitset.test.i64(i8* %addr, i64 %id)`

Then Clang can emit a `__cfi_check` function with weak-odr linkage that uses this intrinsic.


================
Comment at: lib/Transforms/IPO/CrossDSOCFI.cpp:116
@@ +115,3 @@
+                        {Type::getInt64Ty(Ctx),
+                         PointerType::getUnqual(Type::getInt8Ty(Ctx)),
+                         PointerType::getUnqual(Type::getInt8Ty(Ctx))},
----------------
`Type::getInt8PtrTy`

================
Comment at: lib/Transforms/IPO/CrossDSOCFI.cpp:135
@@ +134,3 @@
+  IRBuilder<> IRBFail(TrapBB);
+  Function *CFICheckFailFn = M->getFunction("__cfi_check_fail");
+  assert(CFICheckFailFn || "Module is missing a __cfi_check_fail function");
----------------
Use `getOrCreateFunction`, the function could be defined externally or have a different signature.

================
Comment at: test/Transforms/CrossDSOCFI/basic.ll:16
@@ +15,3 @@
+; CHECK-NEXT:   call void @__cfi_check_fail(i8* %[[DATA]], i8* %[[ADDR]])
+; CHECK-MEXT:   br label %[[EXIT]]
+
----------------
CHECK-NEXT


Repository:
  rL LLVM

http://reviews.llvm.org/D15660