[mc] Add CFI directive to emit val_offset() rules (#113971)

These specify that the value of the given register in the previous frame
is the CFA plus some offset. This isn't very common but can be n

[mc] Add CFI directive to emit val_offset() rules (#113971)

These specify that the value of the given register in the previous frame
is the CFA plus some offset. This isn't very common but can be necessary
if the original value is normally reconstructed from the stack/frame
pointer instead of being saved on the stack and reloaded from there.

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[AArch64][Libunwind] Add Support for FEAT_PAuthLR DWARF Instruction (#112171)

As part of FEAT_PAuthLR, a new DWARF Frame Instruction was introduced,
`DW_CFA_AARCH64_negate_ra_state_with_pc`. This i

[AArch64][Libunwind] Add Support for FEAT_PAuthLR DWARF Instruction (#112171)

As part of FEAT_PAuthLR, a new DWARF Frame Instruction was introduced,
`DW_CFA_AARCH64_negate_ra_state_with_pc`. This instructs Libunwind that
the PC has been used with the signing instruction. This change includes
three commits
- Libunwind support for the newly introduced DWARF Instruction
- CodeGen Support for the DWARF Instructions
- Reversing the changes made in #96377. Due to
`DW_CFA_AARCH64_negate_ra_state_with_pc`'s requirements to be placed
immediately after the signing instruction, this would mean the CFI
Instruction location was not consistent with the generated location when
not using FEAT_PAuthLR. The commit reverses the changes and makes the
location consistent across the different branch protection options.
While this does have a code size effect, this is a negligible one.

For the ABI information, see here:
https://github.com/ARM-software/abi-aa/blob/853286c7ab66048e4b819682ce17f567b77a0291/aadwarf64/aadwarf64.rst#id23

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Spill/restore FP/BP around instructions in which they are clobbered (#81048)

This patch fixes https://github.com/llvm/llvm-project/issues/17204.

If a base pointer is used in a function, and it is

Spill/restore FP/BP around instructions in which they are clobbered (#81048)

This patch fixes https://github.com/llvm/llvm-project/issues/17204.

If a base pointer is used in a function, and it is clobbered by an
instruction (typically an inline asm), current register allocator can't
handle this situation, so BP becomes garbage after those instructions.
It can also occur to FP in theory.

We can spill and reload FP/BP registers around those instructions. But
normal spill/reload instructions also use FP/BP, so we can't spill them
into normal spill slots, instead we spill them into the top of stack by
using SP register.

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[LLVM] [MC] Update frame layout & CFI generation to handle frames larger than 2gb (#99263)

Rebase of #84114. I've only included the core changes to frame layout
calculation & CFI generation which s

[LLVM] [MC] Update frame layout & CFI generation to handle frames larger than 2gb (#99263)

Rebase of #84114. I've only included the core changes to frame layout
calculation & CFI generation which sidesteps the regressions found after
merging #84114. Since these changes are a necessary precursor to the
overall fix and are themselves slightly beneficial as CFI is now
generated correctly, I think it is reasonable to merge this first step.

---

For very large stack frames, the offset from the stack pointer to a
local can be more than 2^31 which overflows various `int` offsets in the
frame lowering code.

This patch updates the frame lowering code to calculate the offsets as
64-bit values and fixes CFI to use the corrected sizes.

After this patch, additional work is needed to fix offset truncations in
each target's codegen.

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[MC] Support .cfi_label

GNU assembler 2.26 introduced the .cfi_label directive. It does not
expand to any CFI instructions, but defines a label in
.eh_frame/.debug_frame, which can be used by runtim

[MC] Support .cfi_label

GNU assembler 2.26 introduced the .cfi_label directive. It does not
expand to any CFI instructions, but defines a label in
.eh_frame/.debug_frame, which can be used by runtime patching code to
locate the FDE. .cfi_label is not allowed for CIE's initial
instructions, and can therefore be used to force the next instruction to
be placed in a FDE instead of a CIE.

In glibc since 2018, sysdeps/riscv/start.S utilizes .cfi_label to force
DW_CFA_undefined to be placed in a FDE. arc/csky/loongarch ports have
copied this use.
```
.cfi_startproc
// DW_CFA_undefined is allowed for CIE's initial instructions.
// Without .cfi_label, gas would place DW_CFA_undefined in a CIE.
.cfi_label .Ldummy
.cfi_undefined ra
.cfi_endproc
```

No CFI instruction is associated with .cfi_label, so the `case
MCCFIInstruction::OpLabel:` code in BOLT is unreachable and onlt to make
-Wswitch happy.

Close #97222

Pull Request: https://github.com/llvm/llvm-project/pull/97922

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Revert rG58de1e2c5eee548a9b365e3b1554d87317072ad9 "Fix stack layout for frames larger than 2gb (#84114)"

This is failing on some EXPENSIVE_CHECKS buildbots

Fix stack layout for frames larger than 2gb (#84114)

For very large stack frames, the offset from the stack pointer to a local can be more than 2^31 which overflows various `int` offsets in the fram

Fix stack layout for frames larger than 2gb (#84114)

For very large stack frames, the offset from the stack pointer to a local can be more than 2^31 which overflows various `int` offsets in the frame lowering code.

This patch updates the frame lowering code to calculate the offsets as 64-bit values and resolves the overflows, resulting in the correct codegen for very large frames.

Fixes #48911

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[CFIInstrInserter] Use number of supported registers (NFC) (#71797)

This makes use of the more accurate register number introduced in PR
#70222 to avoid CFI calculations for unsupported registers.

[CFIInstrInserter] Use number of supported registers (NFC) (#71797)

This makes use of the more accurate register number introduced in PR
#70222 to avoid CFI calculations for unsupported registers.

This has basically no impact right now, but results in a 0.2% compile-time
improvement at O0 when applied on top of #70958.

The reason is that the extra registers that PR adds push the `BitVector`
out of the `SmallVector` space, which results in an outsized impact.
(This does make me wonder whether `BitVector` should accept an `N`
template parameter to allow using a larger `SmallVector`...)

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[X86] Use the CFA when appropriate for better variable locations around calls.

Without frame pointers, the locations of variables on the stack are emitted
relative to the stack pointer (via the stac

[X86] Use the CFA when appropriate for better variable locations around calls.

Without frame pointers, the locations of variables on the stack are emitted
relative to the stack pointer (via the stack pointer being the value of
DW_AT_frame_base on the subprogram). If a call modifies the stack pointer
this results in the locations being wrong and the debugger displaying the
wrong values for variables.

By using DW_OP_call_frame_cfa in these situations the emitted location for
the variable will automatically handle changes in the stack pointer
(provided LLVM is emitting the correct CFI directives elsewhere, of course).
The CFA needs to be adjusted for the size of the stack frame (including the
return address) to allow the variable locations themselves to remain
unchanged by this patch.

Certain LLDB features cannot cope with DW_OP_call_frame_cfa, so this change
is heuristically limited to the cases where it's necessary for correctness
to minimize the fallout there.

Reviewed By: #debug-info, scott.linder, jryans, jmorse

Differential Revision: https://reviews.llvm.org/D143463

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[CodeGen] llvm::Optional => std::optional

[NFC] Use Register instead of unsigned for variables that receive a Register object

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D139451

Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-in

Cleanup codegen includes

This is a (fixed) recommit of https://reviews.llvm.org/D121169

after: 1061034926
before: 1063332844

Discourse thread: https://discourse.llvm.org/t/include-what-you-use-include-cleanup
Differential Revision: https://reviews.llvm.org/D121681

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Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https:/

Revert "Cleanup codegen includes"

This reverts commit 7f230feeeac8a67b335f52bd2e900a05c6098f20.
Breaks CodeGenCUDA/link-device-bitcode.cu in check-clang,
and many LLVM tests, see comments on https://reviews.llvm.org/D121169

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Cleanup codegen includes

after: 1061034926
before: 1063332844

Differential Revision: https://reviews.llvm.org/D121169

[CodeGen] Rename emitCalleeSavedFrameMoves

This diff renames emitCalleeSavedFrameMoves to avoid conflicts with
non-virtual methods of derived classes having the same name but different semantics.
E.

[CodeGen] Rename emitCalleeSavedFrameMoves

This diff renames emitCalleeSavedFrameMoves to avoid conflicts with
non-virtual methods of derived classes having the same name but different semantics.
E.g. the class AArch64FrameLowering used to have (non-virtual) "emitCalleeSavedFrameMoves"
but it started to override TargetFrameLowering::emitCalleeSavedFrameMoves after
https://github.com/llvm/llvm-project/commit/c3e6555616 though its usage and semantics didn't change.
P.S. for x86 there was no conflict because the signature of
non-virtual X86FrameLowering::emitCalleeSavedFrameMoves is different

Test plan: make check-all

Differential revision: https://reviews.llvm.org/D114140

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Implement DW_CFA_LLVM_* for Heterogeneous Debugging

Add support in MC/MIR for writing/parsing, and DebugInfo.

This is part of the Extensions for Heterogeneous Debugging defined at
https://llvm.org/

Implement DW_CFA_LLVM_* for Heterogeneous Debugging

Add support in MC/MIR for writing/parsing, and DebugInfo.

This is part of the Extensions for Heterogeneous Debugging defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html

Specifically the CFI instructions implemented here are defined at
https://llvm.org/docs/AMDGPUDwarfExtensionsForHeterogeneousDebugging.html#cfa-definition-instructions

Reviewed By: clayborg

Differential Revision: https://reviews.llvm.org/D76877

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Introduce a generic operator to apply complex operations to BitVector

This avoids temporary and memcpy call when computing large expressions.

It's basically some kind of poor man's expression templ

Introduce a generic operator to apply complex operations to BitVector

This avoids temporary and memcpy call when computing large expressions.

It's basically some kind of poor man's expression template, but it seems easier
to maintain to have a single generic `apply` call instead of the whole
expression template machinery here.

Differential Revision: https://reviews.llvm.org/D98176

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[NFC] Avoid useless BitVector move

Call Frame Information (CFI) Handling for Basic Block Sections

This patch handles CFI with basic block sections, which unlike DebugInfo does
not support ranges. The DWARF standard explicitly require

Call Frame Information (CFI) Handling for Basic Block Sections

This patch handles CFI with basic block sections, which unlike DebugInfo does
not support ranges. The DWARF standard explicitly requires emitting separate
CFI Frame Descriptor Entries for each contiguous fragment of a function. Thus,
the CFI information for all callee-saved registers (possibly including the
frame pointer, if necessary) have to be emitted along with redefining the
Call Frame Address (CFA), viz. where the current frame starts.

CFI directives are emitted in FDE’s in the object file with a low_pc, high_pc
specification. So, a single FDE must point to a contiguous code region unlike
debug info which has the support for ranges. This is what complicates CFI for
basic block sections.

Now, what happens when we start placing individual basic blocks in unique
sections:

* Basic block sections allow the linker to randomly reorder basic blocks in the
address space such that a given basic block can become non-contiguous with the
original function.
* The different basic block sections can no longer share the cfi_startproc and
cfi_endproc directives. So, each basic block section should emit this
independently.
* Each (cfi_startproc, cfi_endproc) directive will result in a new FDE that
caters to that basic block section.
* Now, this basic block section needs to duplicate the information from the
entry block to compute the CFA as it is an independent entity. It cannot refer
to the FDE of the original function and hence must duplicate all the stuff that
is needed to compute the CFA on its own.
* We are working on a de-duplication patch that can share common information in
FDEs in a CIE (Common Information Entry) and we will present this as a follow up
patch. This can significantly reduce the duplication overhead and is
particularly useful when several basic block sections are created.
* The CFI directives are emitted similarly for registers that are pushed onto
the stack, like callee saved registers in the prologue. There are cfi
directives that emit how to retrieve the value of the register at that point
when the push happened. This has to be duplicated too in a basic block that is
floated as a separate section.

Differential Revision: https://reviews.llvm.org/D79978

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[CFIInstrInserter] Delete unneeded checks

[MC] Change MCCFIInstruction::createDefCfaOffset to cfiDefCfaOffset which does not negate Offset

The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the un

[MC] Change MCCFIInstruction::createDefCfaOffset to cfiDefCfaOffset which does not negate Offset

The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the unneeded negation and fix all call sites.

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[MC] Change MCCFIInstruction::createDefCfa to cfiDefCfa which does not negate Offset

The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the unneeded negat

[MC] Change MCCFIInstruction::createDefCfa to cfiDefCfa which does not negate Offset

The negative Offset has caused a bunch of problems and confused quite a
few call sites. Delete the unneeded negation and fix all call sites.

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Recommit "Generate Callee Saved Register (CSR) related cfi directives
like .cfi_restore"

Insert .cfi_offset/.cfi_register when IncomingCSRSaved of current block
is larger than OutgoingCSRSaved of it

Recommit "Generate Callee Saved Register (CSR) related cfi directives
like .cfi_restore"

Insert .cfi_offset/.cfi_register when IncomingCSRSaved of current block
is larger than OutgoingCSRSaved of its previous block.

Original commit message:
https://reviews.llvm.org/D42848 only handled CFA related cfi directives but
didn't handle CSR related cfi. The patch adds the CSR part. Basically it reuses
the framework created in D42848. For each basicblock, the patch tracks which
CSR set have been saved at its CFG predecessors's exits, and compare the CSR
set with the set at its previous basicblock's exit (The previous block is the
block laid before the current block). If the saved CSR set at its previous
basicblock's exit is larger, .cfi_restore will be inserted.

The patch also generates proper .cfi_restore in epilogue to make sure the
saved CSR set is consistent for the incoming edges of each block.

Differential Revision: https://reviews.llvm.org/D74303

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Revert "Generate Callee Saved Register (CSR) related cfi directives like .cfi_restore."

This reverts commit 3c96d01d2e3de63304ca3429d349ec62ae2adef3. Got report that it caused test failures in libc+

Revert "Generate Callee Saved Register (CSR) related cfi directives like .cfi_restore."

This reverts commit 3c96d01d2e3de63304ca3429d349ec62ae2adef3. Got report that it caused test failures in libc++.

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Generate Callee Saved Register (CSR) related cfi directives like .cfi_restore.

https://reviews.llvm.org/D42848 only handled CFA related cfi directives but
didn't handle CSR related cfi. The patch ad

Generate Callee Saved Register (CSR) related cfi directives like .cfi_restore.

https://reviews.llvm.org/D42848 only handled CFA related cfi directives but
didn't handle CSR related cfi. The patch adds the CSR part. Basically it reuses
the framework created in D42848. For each basicblock, the patch tracks which
CSR set have been saved at its CFG predecessors's exits, and compare the CSR
set with the set at its previous basicblock's exit (The previous block is the
block laid before the current block). If the saved CSR set at its previous
basicblock's exit is larger, .cfi_restore will be inserted.

The patch also generates proper .cfi_restore in epilogue to make sure the
saved CSR set is consistent for the incoming edges of each block.

Differential Revision: https://reviews.llvm.org/D74303

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