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Add CFI integer types normalization

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This commit adds a new option (i.e.,
`-fsanitize-cfi-icall-normalize-integers`) for normalizing integer types
as vendor extended types for cross-language LLVM CFI/KCFI support with
other languages that can't represent and encode C/C++ integer types.

Specifically, integer types are encoded as their defined representations
(e.g., 8-bit signed integer, 16-bit signed integer, 32-bit signed
integer, ...) for compatibility with languages that define
explicitly-sized integer types (e.g., i8, i16, i32, ..., in Rust).

``-fsanitize-cfi-icall-normalize-integers`` is compatible with
``-fsanitize-cfi-icall-generalize-pointers``.

This helps with providing cross-language CFI support with the Rust
compiler and is an alternative solution for the issue described and
alternatives proposed in the RFC
https://github.com/rust-lang/rfcs/pull/3296.

For more information about LLVM CFI/KCFI and cross-language LLVM
CFI/KCFI support for the Rust compiler, see the design document in the
tracking issue https://github.com/rust-lang/rust/issues/89653.

Reviewed By: pcc, samitolvanen

Differential Revision: https://reviews.llvm.org/D139395
This commit is contained in:
Ramon de C Valle
2023-02-01 16:42:28 +00:00
committed by Sami Tolvanen
parent 6e3d12951d
commit b1e9ab7438
13 changed files with 300 additions and 16 deletions
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13
clang/lib/CodeGen/CodeGenModule.cpp
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@@ -1727,7 +1727,11 @@ llvm::ConstantInt *CodeGenModule::CreateKCFITypeId(QualType T) {
std::string OutName;
llvm::raw_string_ostream Out(OutName);
getCXXABI().getMangleContext().mangleTypeName(T, Out);
getCXXABI().getMangleContext().mangleTypeName(
T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
Out << ".normalized";
return llvm::ConstantInt::get(Int32Ty,
static_cast<uint32_t>(llvm::xxHash64(OutName)));
@@ -6945,7 +6949,12 @@ CodeGenModule::CreateMetadataIdentifierImpl(QualType T, MetadataTypeMap &Map,
if (isExternallyVisible(T->getLinkage())) {
std::string OutName;
llvm::raw_string_ostream Out(OutName);
getCXXABI().getMangleContext().mangleTypeName(T, Out);
getCXXABI().getMangleContext().mangleTypeName(
T, Out, getCodeGenOpts().SanitizeCfiICallNormalizeIntegers);
if (getCodeGenOpts().SanitizeCfiICallNormalizeIntegers)
Out << ".normalized";
Out << Suffix;
InternalId = llvm::MDString::get(getLLVMContext(), Out.str());