From 20183554a4b49b71794e7c022fd5b2ae4a7b9a2f Mon Sep 17 00:00:00 2001
From: Jakob Olesen <jolesen@mozilla.com>
Date: Fri, 12 Feb 2016 14:24:01 -0800
Subject: [PATCH] Add Instruction and Operand classes to the meta language.

---
 cranelift/docs/cton_domain.py | 44 +++++++++++++++++++++
 cranelift/docs/metaref.rst    |  9 +++++
 meta/cretonne/__init__.py     | 72 ++++++++++++++++++++++++++++++++++-
 3 files changed, 124 insertions(+), 1 deletion(-)

diff --git a/cranelift/docs/cton_domain.py b/cranelift/docs/cton_domain.py
index 823ed9c8a5..6f20cf8d32 100644
--- a/cranelift/docs/cton_domain.py
+++ b/cranelift/docs/cton_domain.py
@@ -242,8 +242,52 @@ class TypeDocumenter(sphinx.ext.autodoc.Documenter):
             self.add_line(u':bytes: Can\'t be stored in memory', sourcename)
 
 
+class InstDocumenter(sphinx.ext.autodoc.Documenter):
+    # Invoke with .. autoinst::
+    objtype = 'inst'
+    # Convert into cton:inst directives
+    domain = 'cton'
+    directivetype = 'inst'
+
+    @classmethod
+    def can_document_member(cls, member, membername, isattr, parent):
+        return False
+
+    def resolve_name(self, modname, parents, path, base):
+        return 'cretonne.base', [ base ]
+
+    def format_signature(self):
+        inst = self.object
+        sig = self.format_name()
+        if len(inst.outs) > 0:
+            sig = ', '.join([op.name for op in inst.outs]) + ' = ' + sig
+        if len(inst.ins) > 0:
+            sig = sig + ' ' + ', '.join([op.name for op in inst.ins])
+        return sig
+
+    def add_directive_header(self, sig):
+        """Add the directive header and options to the generated content."""
+        domain = getattr(self, 'domain', 'cton')
+        directive = getattr(self, 'directivetype', self.objtype)
+        sourcename = self.get_sourcename()
+        self.add_line(u'.. %s:%s:: %s' % (domain, directive, sig), sourcename)
+        if self.options.noindex:
+            self.add_line(u'   :noindex:', sourcename)
+
+    def add_content(self, more_content, no_docstring=False):
+        super(InstDocumenter, self).add_content(more_content, no_docstring)
+        sourcename = self.get_sourcename()
+
+        # Add inputs and outputs.
+        for op in self.object.ins:
+            self.add_line(u':in {} {}: {}'.format(op.typ.name, op.name, op.get_doc()), sourcename)
+        for op in self.object.outs:
+            self.add_line(u':out {} {}: {}'.format(op.typ.name, op.name, op.get_doc()), sourcename)
+
+
 def setup(app):
     app.add_domain(CretonneDomain)
     app.add_autodocumenter(TypeDocumenter)
+    app.add_autodocumenter(InstDocumenter)
 
     return { 'version' : '0.1' }
diff --git a/cranelift/docs/metaref.rst b/cranelift/docs/metaref.rst
index b4dda9576d..8d58757b81 100644
--- a/cranelift/docs/metaref.rst
+++ b/cranelift/docs/metaref.rst
@@ -63,3 +63,12 @@ indicated with an instance of :class:`ImmediateType`.
     :members:
 
 .. currentmodule:: cretonne
+
+Instructions
+============
+
+New instructions are defined as instances of the :class:`cretonne.Instruction`
+class.
+
+.. autoclass:: Operand
+.. autoclass:: Instruction
diff --git a/meta/cretonne/__init__.py b/meta/cretonne/__init__.py
index 60c3748106..fd0c4664dd 100644
--- a/meta/cretonne/__init__.py
+++ b/meta/cretonne/__init__.py
@@ -107,8 +107,9 @@ class TypeVar(object):
     instructions. This makes the instructions *polymorphic*.
     """
 
-    def __init__(self, name):
+    def __init__(self, name, doc):
         self.name = name
+        self.__doc__ = doc
 
 #
 # Immediate operands.
@@ -130,3 +131,72 @@ class ImmediateType(object):
 
     def __repr__(self):
         return 'ImmediateType({})'.format(self.name)
+
+#
+# Defining instructions.
+#
+
+class Operand(object):
+    """
+    An instruction operand.
+
+    An instruction operand can be either an *immediate* or an *SSA value*. The
+    type of the operand is one of:
+
+    1. A :py:class:`Type` instance indicates an SSA value operand with a
+       concrete type.
+
+    2. A :py:class:`TypeVar` instance indicates an SSA value operand, and the
+       instruction is polymorphic over the possible concrete types that the type
+       variable can assume.
+
+    3. An :py:class:`ImmediateType` instance indicates an immediate operand
+       whose value is encoded in the instruction itself rather than being passed
+       as an SSA value.
+
+    """
+    def __init__(self, name, typ, doc=''):
+        self.name = name
+        self.typ = typ
+        self.__doc__ = doc
+
+    def get_doc(self):
+        if self.__doc__:
+            return self.__doc__
+        else:
+            return self.typ.__doc__
+
+class Instruction(object):
+    """
+    An instruction.
+
+    The operands to the instruction are specified as two tuples: ``ins`` and
+    ``outs``. Since the Python singleton tuple syntax is a bit awkward, it is
+    allowed to specify a singleton as just the operand itself, i.e., `ins=x` and
+    `ins=(x,)` are both allowed and mean the same thing.
+
+    :param name: Instruction mnemonic, also becomes opcode name.
+    :param doc: Documentation string.
+    :param ins: Tuple of input operands. This can be a mix of SSA value operands
+                and immediate operands.
+    :param outs: Tuple of output operands. The output operands can't be
+                 immediates.
+    """
+
+    def __init__(self, name, doc, ins=(), outs=(), **kwargs):
+        self.name = name
+        self.__doc__ = doc
+        self.ins = self._to_operand_tuple(ins)
+        self.outs = self._to_operand_tuple(outs)
+
+    @staticmethod
+    def _to_operand_tuple(x):
+        # Allow a single Operand instance instead of the awkward singleton tuple
+        # syntax.
+        if isinstance(x, Operand):
+            x = (x,)
+        else:
+            x = tuple(x)
+        for op in x:
+            assert isinstance(op, Operand)
+        return x