[PATCH] D138337: Add support for kcfi-seal optimization with LTO

[Sami Tolvanen via Phabricator via cfe-commits]

samitolvanen created this revision.
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With -fsanitize=kcfi, Clang emits a !kcfi_type attribute for all global
functions, making them valid indirect call targets, whether the program
ends up calling them indirectly or not. With LTO, we can "seal" the
program by dropping types from non-address-taken globals, thus limiting
the possible targets that can be called.

Add -fsanitize-kcfi-seal command line flag to Clang that's only allowed
with -flto, and drop types from non-address-taken globals in AsmPrinter
when the kcfi-seal module attribute is set.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D138337

Files:
  clang/include/clang/Basic/CodeGenOptions.def
  clang/include/clang/Driver/Options.td
  clang/include/clang/Driver/SanitizerArgs.h
  clang/lib/CodeGen/CodeGenModule.cpp
  clang/lib/Driver/SanitizerArgs.cpp
  clang/test/CodeGen/kcfi.c
  clang/test/Driver/fsanitize.c
  llvm/include/llvm/CodeGen/AsmPrinter.h
  llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
  llvm/test/CodeGen/X86/kcfi-seal.ll

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