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Revision tags: llvmorg-20.1.0, llvmorg-20.1.0-rc3, llvmorg-20.1.0-rc2, llvmorg-20.1.0-rc1, llvmorg-21-init, llvmorg-19.1.7, llvmorg-19.1.6, llvmorg-19.1.5, llvmorg-19.1.4, llvmorg-19.1.3, llvmorg-19.1.2, llvmorg-19.1.1, llvmorg-19.1.0, llvmorg-19.1.0-rc4, llvmorg-19.1.0-rc3, llvmorg-19.1.0-rc2, llvmorg-19.1.0-rc1, llvmorg-20-init, llvmorg-18.1.8, llvmorg-18.1.7, llvmorg-18.1.6, llvmorg-18.1.5, llvmorg-18.1.4, llvmorg-18.1.3, llvmorg-18.1.2, llvmorg-18.1.1, llvmorg-18.1.0, llvmorg-18.1.0-rc4, llvmorg-18.1.0-rc3, llvmorg-18.1.0-rc2, llvmorg-18.1.0-rc1, llvmorg-19-init, llvmorg-17.0.6, llvmorg-17.0.5, llvmorg-17.0.4, llvmorg-17.0.3, llvmorg-17.0.2, llvmorg-17.0.1, llvmorg-17.0.0, llvmorg-17.0.0-rc4, llvmorg-17.0.0-rc3, llvmorg-17.0.0-rc2, llvmorg-17.0.0-rc1, llvmorg-18-init, llvmorg-16.0.6, llvmorg-16.0.5, llvmorg-16.0.4, llvmorg-16.0.3, llvmorg-16.0.2, llvmorg-16.0.1, llvmorg-16.0.0, llvmorg-16.0.0-rc4, llvmorg-16.0.0-rc3, llvmorg-16.0.0-rc2, llvmorg-16.0.0-rc1, llvmorg-17-init, llvmorg-15.0.7, llvmorg-15.0.6, llvmorg-15.0.5, llvmorg-15.0.4, llvmorg-15.0.3, llvmorg-15.0.2, llvmorg-15.0.1, llvmorg-15.0.0, llvmorg-15.0.0-rc3, llvmorg-15.0.0-rc2, llvmorg-15.0.0-rc1, llvmorg-16-init, llvmorg-14.0.6, llvmorg-14.0.5, llvmorg-14.0.4, llvmorg-14.0.3, llvmorg-14.0.2, llvmorg-14.0.1, llvmorg-14.0.0, llvmorg-14.0.0-rc4, llvmorg-14.0.0-rc3, llvmorg-14.0.0-rc2, llvmorg-14.0.0-rc1, llvmorg-15-init, llvmorg-13.0.1, llvmorg-13.0.1-rc3, llvmorg-13.0.1-rc2, llvmorg-13.0.1-rc1, llvmorg-13.0.0, llvmorg-13.0.0-rc4, llvmorg-13.0.0-rc3, llvmorg-13.0.0-rc2, llvmorg-13.0.0-rc1, llvmorg-14-init, llvmorg-12.0.1, llvmorg-12.0.1-rc4, llvmorg-12.0.1-rc3, llvmorg-12.0.1-rc2, llvmorg-12.0.1-rc1, llvmorg-12.0.0, llvmorg-12.0.0-rc5, llvmorg-12.0.0-rc4
# cca40aa8 24-Mar-2021 Pablo Barrio <[email protected]>

[AArch64][v8.5A] Add BTI to all function starts

The existing BTI placement pass avoids inserting "BTI c" when the
function has local linkage and is only directly called. However,
even in this case,

[AArch64][v8.5A] Add BTI to all function starts

The existing BTI placement pass avoids inserting "BTI c" when the
function has local linkage and is only directly called. However,
even in this case, there is a (small) chance that the linker later
adds a hunk with an indirect call to the function, e.g. if the
function is placed in a separate section and moved far away from
its callers. Make sure to add BTI for these functions too.

Differential Revision: https://reviews.llvm.org/D99417

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Revision tags: llvmorg-12.0.0-rc3, llvmorg-12.0.0-rc2, llvmorg-11.1.0, llvmorg-11.1.0-rc3, llvmorg-12.0.0-rc1, llvmorg-13-init, llvmorg-11.1.0-rc2, llvmorg-11.1.0-rc1, llvmorg-11.0.1, llvmorg-11.0.1-rc2, llvmorg-11.0.1-rc1, llvmorg-11.0.0, llvmorg-11.0.0-rc6, llvmorg-11.0.0-rc5, llvmorg-11.0.0-rc4
# a88c722e 25-Sep-2020 Momchil Velikov <[email protected]>

[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, b

[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

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Revision tags: llvmorg-11.0.0-rc3, llvmorg-11.0.0-rc2, llvmorg-11.0.0-rc1, llvmorg-12-init, llvmorg-10.0.1, llvmorg-10.0.1-rc4, llvmorg-10.0.1-rc3, llvmorg-10.0.1-rc2, llvmorg-10.0.1-rc1, llvmorg-10.0.0, llvmorg-10.0.0-rc6, llvmorg-10.0.0-rc5, llvmorg-10.0.0-rc4, llvmorg-10.0.0-rc3
# f554e272 15-Feb-2020 Fangrui Song <[email protected]>

[AsmPrinter] Omit unique ID for __patchable_function_entries sections

Follow-up for D74006.

When the integrated assembler is used, we use SHF_LINK_ORDER. The
linked-to symbol is part of ELFSection

[AsmPrinter] Omit unique ID for __patchable_function_entries sections

Follow-up for D74006.

When the integrated assembler is used, we use SHF_LINK_ORDER. The
linked-to symbol is part of ELFSectionKey, thus we can omit the unique
ID.

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Revision tags: llvmorg-10.0.0-rc2
# 0fbe2215 04-Feb-2020 Fangrui Song <[email protected]>

[MC][ELF] Make linked-to symbol name part of ELFSectionKey

https://bugs.llvm.org/show_bug.cgi?id=44775

This rule has been implemented by GNU as https://sourceware.org/ml/binutils/2020-02/msg00028.h

[MC][ELF] Make linked-to symbol name part of ELFSectionKey

https://bugs.llvm.org/show_bug.cgi?id=44775

This rule has been implemented by GNU as https://sourceware.org/ml/binutils/2020-02/msg00028.html (binutils >= 2.35)

It allows us to simplify

```
.section .foo,"o",foo,unique,0
.section .foo,"o",bar,unique,1 # different section
```

to

```
.section .foo,"o",foo
.section .foo,"o",bar # different section
```

We consider the two `.foo` different even if the linked-to symbols foo and bar
are defined in the same section. This is a deliberate choice so that we don't
need to know the section where foo and bar are defined beforehand.

Differential Revision: https://reviews.llvm.org/D74006

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# 8ff86fcf 31-Jan-2020 Fangrui Song <[email protected]>

[X86] -fpatchable-function-entry=N,0: place patch label after ENDBR{32,64}

Similar to D73680 (AArch64 BTI).

A local linkage function whose address is not taken does not need ENDBR32/ENDBR64. Placin

[X86] -fpatchable-function-entry=N,0: place patch label after ENDBR{32,64}

Similar to D73680 (AArch64 BTI).

A local linkage function whose address is not taken does not need ENDBR32/ENDBR64. Placing the patch label after ENDBR32/ENDBR64 has the advantage that code does not need to differentiate whether the function has an initial ENDBR.

Also, add 32-bit tests and test that .cfi_startproc is at the function
entry. The line information has a general implementation and is tested
by AArch64/patchable-function-entry-empty.mir

Reviewed By: nickdesaulniers

Differential Revision: https://reviews.llvm.org/D73760

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Revision tags: llvmorg-10.0.0-rc1
# 06b8e32d 30-Jan-2020 Fangrui Song <[email protected]>

[AArch64] -fpatchable-function-entry=N,0: place patch label after BTI

Summary:
For -fpatchable-function-entry=N,0 -mbranch-protection=bti, after
9a24488cb67a90f889529987275c5e411ce01dda, we place th

[AArch64] -fpatchable-function-entry=N,0: place patch label after BTI

Summary:
For -fpatchable-function-entry=N,0 -mbranch-protection=bti, after
9a24488cb67a90f889529987275c5e411ce01dda, we place the NOP sled after
the initial BTI.

```
.Lfunc_begin0:
bti c
nop
nop

.section __patchable_function_entries,"awo",@progbits,f,unique,0
.p2align 3
.xword .Lfunc_begin0
```

This patch adds a label after the initial BTI and changes the __patchable_function_entries entry to reference the label:

```
.Lfunc_begin0:
bti c
.Lpatch0:
nop
nop

.section __patchable_function_entries,"awo",@progbits,f,unique,0
.p2align 3
.xword .Lpatch0
```

This placement is compatible with the resolution in
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92424 .

A local linkage function whose address is not taken does not need a BTI.
Placing the patch label after BTI has the advantage that code does not
need to differentiate whether the function has an initial BTI.

Reviewers: mrutland, nickdesaulniers, nsz, ostannard

Subscribers: kristof.beyls, hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73680

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# 22467e25 20-Jan-2020 Fangrui Song <[email protected]>

Add function attribute "patchable-function-prefix" to support -fpatchable-function-entry=N,M where M>0

Similar to the function attribute `prefix` (prefix data),
"patchable-function-prefix" inserts d

Add function attribute "patchable-function-prefix" to support -fpatchable-function-entry=N,M where M>0

Similar to the function attribute `prefix` (prefix data),
"patchable-function-prefix" inserts data (M NOPs) before the function
entry label.

-fpatchable-function-entry=2,1 (1 NOP before entry, 1 NOP after entry)
will look like:

```
.type foo,@function
.Ltmp0: # @foo
nop
foo:
.Lfunc_begin0:
# optional `bti c` (AArch64 Branch Target Identification) or
# `endbr64` (Intel Indirect Branch Tracking)
nop

.section __patchable_function_entries,"awo",@progbits,get,unique,0
.p2align 3
.quad .Ltmp0
```

-fpatchable-function-entry=N,0 + -mbranch-protection=bti/-fcf-protection=branch has two reasonable
placements (https://gcc.gnu.org/ml/gcc-patches/2020-01/msg01185.html):

```
(a) (b)

func: func:
.Ltmp0: bti c
bti c .Ltmp0:
nop nop
```

(a) needs no additional code. If the consensus is to go for (b), we will
need more code in AArch64BranchTargets.cpp / X86IndirectBranchTracking.cpp .

Differential Revision: https://reviews.llvm.org/D73070

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# d232c215 20-Jan-2020 Fangrui Song <[email protected]>

[AsmPrinter] Don't emit __patchable_function_entries entry if "patchable-function-entry"="0"

Add improve tests


# 9a24488c 19-Jan-2020 Fangrui Song <[email protected]>

[CodeGen] Move fentry-insert, xray-instrumentation and patchable-function before addPreEmitPass()

This intention is to move patchable-function before aarch64-branch-targets
(configured in AArch64Pas

[CodeGen] Move fentry-insert, xray-instrumentation and patchable-function before addPreEmitPass()

This intention is to move patchable-function before aarch64-branch-targets
(configured in AArch64PassConfig::addPreEmitPass) so that we emit BTI before NOPs
(see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92424).

This also allows addPreEmitPass() passes to know the precise instruction sizes if they want.

Tried x86-64 Debug/Release builds of ccls with -fxray-instrument -fxray-instruction-threshold=1.
No output difference with this commit and the previous commit.

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