[clang] [llvm] [llvm][fatlto] Add FatLTOCleanup pass (PR #125911)

[via llvm-commits]

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@@ -44,3 +47,44 @@ void foo(const void* ptr, size_t len, long disp_addr,
   }
 }
 
+//--- b.cpp
+// COM: Prior to the introduction of the FatLTO cleanup pass, this used to cause
+// COM: the backend to crash, either due to an assertion failure, or because
+// COM: the CFI instructions couldn't be correctly generated. So, check to make
+// COM: sure that the FatLTO pipeline used by clang does not regress.
+
+// COM: Check the generated IR doesn't contain llvm.type.checked.load in the final IR.
+// RUN: %clang_cc1 -triple=x86_64-unknown-fuchsia -O1 -emit-llvm -o - \
+// RUN:      -ffat-lto-objects -fvisibility=hidden \
+// RUN:      -fno-rtti -fsanitize=cfi-icall,cfi-mfcall,cfi-nvcall,cfi-vcall \
+// RUN:      -fsanitize-trap=cfi-icall,cfi-mfcall,cfi-nvcall,cfi-vcall \
+// RUN:      -fwhole-program-vtables %t/b.cpp 2>&1 | FileCheck %s --check-prefix=NO_CHECKED_LOAD
+
+// RUN: %clang_cc1 -triple=x86_64-unknown-fuchsia -O1 -emit-llvm -o - \
+// RUN:      -ffat-lto-objects -fvisibility=hidden -fexperimental-relative-c++-abi-vtables \
+// RUN:      -fno-rtti -fsanitize=cfi-icall,cfi-mfcall,cfi-nvcall,cfi-vcall \
+// RUN:      -fsanitize-trap=cfi-icall,cfi-mfcall,cfi-nvcall,cfi-vcall \
+// RUN:      -fwhole-program-vtables %t/b.cpp 2>&1 | FileCheck %s --check-prefix=NO_CHECKED_LOAD
+
+// COM: Note that the embedded bitcode section will contain references to
+// COM: llvm.type.checked.load, so we need to match the function body first.
+// NO_CHECKED_LOAD-LABEL: entry:
+// NO_CHECKED_LOAD-NEXT:    %vtable = load ptr, ptr %p1
+// NO_CHECKED_LOAD-NOT:   llvm.type.checked.load
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PiJoules wrote:

Clang should technically emit a `llvm.type.checked.load.relative` here, but that's because of something I missed. I'll send out a patch that fixes this.

https://github.com/llvm/llvm-project/pull/125911