2019-12-14 01:37:22 +08:00
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; RUN: llc -mtriple=aarch64-linux %s -o - | \
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; RUN: FileCheck %s --check-prefix=ASM
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define dso_local i32 @f() #0 {
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entry:
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ret i32 0
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}
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define dso_local i32 @g() #1 {
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entry:
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ret i32 0
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}
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[AArch64] PAC/BTI code generation for LLVM generated functions
PAC/BTI-related codegen in the AArch64 backend is controlled by a set
of LLVM IR function attributes, added to the function by Clang, based
on command-line options and GCC-style function attributes. However,
functions, generated in the LLVM middle end (for example,
asan.module.ctor or __llvm_gcov_write_out) do not get any attributes
and the backend incorrectly does not do any PAC/BTI code generation.
This patch record the default state of PAC/BTI codegen in a set of
LLVM IR module-level attributes, based on command-line options:
* "sign-return-address", with non-zero value means generate code to
sign return addresses (PAC-RET), zero value means disable PAC-RET.
* "sign-return-address-all", with non-zero value means enable PAC-RET
for all functions, zero value means enable PAC-RET only for
functions, which spill LR.
* "sign-return-address-with-bkey", with non-zero value means use B-key
for signing, zero value mean use A-key.
This set of attributes are always added for AArch64 targets (as
opposed, for example, to interpreting a missing attribute as having a
value 0) in order to be able to check for conflicts when combining
module attributed during LTO.
Module-level attributes are overridden by function level attributes.
All the decision making about whether to not to generate PAC and/or
BTI code is factored out into AArch64FunctionInfo, there shouldn't be
any places left, other than AArch64FunctionInfo, which directly
examine PAC/BTI attributes, except AArch64AsmPrinter.cpp, which
is/will-be handled by a separate patch.
Differential Revision: https://reviews.llvm.org/D85649
2020-09-25 18:45:22 +08:00
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attributes #0 = { "branch-target-enforcement"="true" "sign-return-address"="non-leaf" }
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2019-12-14 01:37:22 +08:00
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[AArch64] PAC/BTI code generation for LLVM generated functions
PAC/BTI-related codegen in the AArch64 backend is controlled by a set
of LLVM IR function attributes, added to the function by Clang, based
on command-line options and GCC-style function attributes. However,
functions, generated in the LLVM middle end (for example,
asan.module.ctor or __llvm_gcov_write_out) do not get any attributes
and the backend incorrectly does not do any PAC/BTI code generation.
This patch record the default state of PAC/BTI codegen in a set of
LLVM IR module-level attributes, based on command-line options:
* "sign-return-address", with non-zero value means generate code to
sign return addresses (PAC-RET), zero value means disable PAC-RET.
* "sign-return-address-all", with non-zero value means enable PAC-RET
for all functions, zero value means enable PAC-RET only for
functions, which spill LR.
* "sign-return-address-with-bkey", with non-zero value means use B-key
for signing, zero value mean use A-key.
This set of attributes are always added for AArch64 targets (as
opposed, for example, to interpreting a missing attribute as having a
value 0) in order to be able to check for conflicts when combining
module attributed during LTO.
Module-level attributes are overridden by function level attributes.
All the decision making about whether to not to generate PAC and/or
BTI code is factored out into AArch64FunctionInfo, there shouldn't be
any places left, other than AArch64FunctionInfo, which directly
examine PAC/BTI attributes, except AArch64AsmPrinter.cpp, which
is/will-be handled by a separate patch.
Differential Revision: https://reviews.llvm.org/D85649
2020-09-25 18:45:22 +08:00
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attributes #1 = { "branch-target-enforcement"="true" }
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2019-12-14 01:37:22 +08:00
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2020-09-28 19:57:21 +08:00
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!llvm.module.flags = !{!0, !1, !2, !3}
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2019-12-14 01:37:22 +08:00
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2020-09-28 19:57:21 +08:00
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!0 = !{i32 1, !"branch-target-enforcement", i32 0}
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!1 = !{i32 1, !"sign-return-address", i32 0}
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!2 = !{i32 1, !"sign-return-address-all", i32 0}
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!3 = !{i32 1, !"sign-return-address-with-bkey", i32 0}
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; Note is not emited if module has no properties
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; ASM-NOT: .note.gnu.property
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