name: inc
tracksRegLiveness: true
liveins:
- - { reg: '%rdi' }
+ - { reg: '$rdi' }
body: |
bb.0.entry:
- liveins: %rdi
+ liveins: $rdi
- %eax = MOV32rm %rdi, 1, _, 0, _
- %eax = INC32r killed %eax, implicit-def dead %eflags
- MOV32mr killed %rdi, 1, _, 0, _, %eax
- RETQ %eax
+ $eax = MOV32rm $rdi, 1, _, 0, _
+ $eax = INC32r killed $eax, implicit-def dead $eflags
+ MOV32mr killed $rdi, 1, _, 0, _, $eax
+ RETQ $eax
...
The document above consists of attributes that represent the various
.. code-block:: text
bb.0.entry:
- liveins: %edi, %esi
+ liveins: $edi, $esi
The list of live in registers and successors can be empty. The language also
allows multiple live in register and successor lists - they are combined into
.. code-block:: text
- RETQ %eax
+ RETQ $eax
However, if the machine instruction has one or more explicitly defined register
operands, the instruction's name has to be specified after them. The example
.. code-block:: text
- %sp, %fp, %lr = LDPXpost %sp, 2
+ $sp, $fp, $lr = LDPXpost $sp, 2
The instruction names are serialized using the exact definitions from the
target's ``*InstrInfo.td`` files, and they are case sensitive. This means that
Instruction Flags
^^^^^^^^^^^^^^^^^
-The flag ``frame-setup`` can be specified before the instruction's name:
+The flag ``frame-setup`` or ``frame-destroy`` can be specified before the
+instruction's name:
.. code-block:: text
- %fp = frame-setup ADDXri %sp, 0, 0
+ $fp = frame-setup ADDXri $sp, 0, 0
+
+.. code-block:: text
+
+ $x21, $x20 = frame-destroy LDPXi $sp
.. _registers:
+Bundled Instructions
+^^^^^^^^^^^^^^^^^^^^
+
+The syntax for bundled instructions is the following:
+
+.. code-block:: text
+
+ BUNDLE implicit-def $r0, implicit-def $r1, implicit $r2 {
+ $r0 = SOME_OP $r2
+ $r1 = ANOTHER_OP internal $r0
+ }
+
+The first instruction is often a bundle header. The instructions between ``{``
+and ``}`` are bundled with the first instruction.
+
Registers
---------
Registers are one of the key primitives in the machine instructions
-serialization language. They are primarly used in the
+serialization language. They are primarily used in the
:ref:`register machine operands <register-operands>`,
but they can also be used in a number of other places, like the
:ref:`basic block's live in list <bb-liveins>`.
-The physical registers are identified by their name. They use the following
-syntax:
+The physical registers are identified by their name and by the '$' prefix sigil.
+They use the following syntax:
.. code-block:: text
- %<name>
+ $<name>
The example below shows three X86 physical registers:
.. code-block:: text
- %eax
- %r15
- %eflags
+ $eax
+ $r15
+ $eflags
-The virtual registers are identified by their ID number. They use the following
-syntax:
+The virtual registers are identified by their ID number and by the '%' sigil.
+They use the following syntax:
.. code-block:: text
%0
The null registers are represented using an underscore ('``_``'). They can also be
-represented using a '``%noreg``' named register, although the former syntax
+represented using a '``$noreg``' named register, although the former syntax
is preferred.
.. _machine-operands:
.. code-block:: text
- %eax = MOV32ri -42
+ $eax = MOV32ri -42
An immediate operand is also used to represent a subregister index when the
machine instruction has one of the following opcodes:
.. code-block:: text
- dead %eax = XOR32rr undef %eax, undef %eax, implicit-def dead %eflags, implicit-def %al
+ dead $eax = XOR32rr undef $eax, undef $eax, implicit-def dead $eflags, implicit-def $al
.. _register-flags:
.. code-block:: text
- %rax = MOV64rm %rip, 1, _, @G, _
+ $rax = MOV64rm $rip, 1, _, @G, _
The named global values are represented using an identifier with the '@' prefix.
If the identifier doesn't match the regular expression
.. code-block:: text
- %sgpr2 = S_ADD_U32 _, target-index(amdgpu-constdata-start) + 8, implicit-def _, implicit-def _
+ $sgpr2 = S_ADD_U32 _, target-index(amdgpu-constdata-start) + 8, implicit-def _, implicit-def _
Jump-table Index Operands
^^^^^^^^^^^^^^^^^^^^^^^^^
.. code-block:: text
- tBR_JTr killed %r0, %jump-table.0
+ tBR_JTr killed $r0, %jump-table.0
A machine jump-table entry contains a list of ``MachineBasicBlocks``. When serializing all the function's jump-table entries, the following format is used:
External Symbol Operands
^^^^^^^^^^^^^^^^^^^^^^^^^
-An external symbol operand is represented using an identifier with the ``$``
+An external symbol operand is represented using an identifier with the ``&``
prefix. The identifier is surrounded with ""'s and escaped if it has any
special non-printable characters in it.
.. code-block:: text
- CALL64pcrel32 $__stack_chk_fail, csr_64, implicit %rsp, implicit-def %rsp
+ CALL64pcrel32 &__stack_chk_fail, csr_64, implicit $rsp, implicit-def $rsp
MCSymbol Operands
^^^^^^^^^^^^^^^^^
.. code-block:: text
- CFI_INSTRUCTION offset %w30, -16
+ CFI_INSTRUCTION offset $w30, -16
which may be emitted later in the MC layer as:
.. code-block:: text
- %x0 = COPY intrinsic(@llvm.returnaddress)
+ $x0 = COPY intrinsic(@llvm.returnaddress)
Predicate Operands
^^^^^^^^^^^^^^^^^^
.. TODO: Describe the parsers default behaviour when optional YAML attributes
are missing.
-.. TODO: Describe the syntax for the bundled instructions.
.. TODO: Describe the syntax for virtual register YAML definitions.
.. TODO: Describe the machine function's YAML flag attributes.
.. TODO: Describe the syntax for the register mask machine operands.
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