From eba396546a76ee720d948ac74172798308da363b Mon Sep 17 00:00:00 2001
From: Jakob Stoklund Olesen <jolesen@mozilla.com>
Date: Wed, 6 Apr 2016 10:45:06 -0700
Subject: [PATCH] Begin source generation.

Start out easy by emiting an opcodes.rs file containing an opcode enumeration.
---
 meta/build.py     |  6 ++++
 meta/gen_instr.py | 31 ++++++++++++++++++++
 meta/srcgen.py    | 73 +++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 110 insertions(+)
 create mode 100644 meta/gen_instr.py
 create mode 100644 meta/srcgen.py

diff --git a/meta/build.py b/meta/build.py
index 2cdda53403..76673fa62b 100644
--- a/meta/build.py
+++ b/meta/build.py
@@ -3,9 +3,15 @@
 # This script is run from src/libcretonne/build.rs to generate Rust files.
 
 import argparse
+import target
+import gen_instr
 
 parser = argparse.ArgumentParser(description='Generate sources for Cretonne.')
 parser.add_argument('--out-dir', help='set output directory')
 
 args = parser.parse_args()
 out_dir = args.out_dir
+
+targets = target.all_targets()
+
+gen_instr.generate(targets, out_dir)
diff --git a/meta/gen_instr.py b/meta/gen_instr.py
new file mode 100644
index 0000000000..a92609c861
--- /dev/null
+++ b/meta/gen_instr.py
@@ -0,0 +1,31 @@
+"""
+Generate sources with instruction info.
+"""
+
+import srcgen
+
+def collect_instr_groups(targets):
+    seen = set()
+    groups = []
+    for t in targets:
+        for g in t.instruction_groups:
+            if g not in seen:
+                groups.append(g)
+                seen.add(g)
+    return groups
+
+def gen_opcodes(groups, out_dir):
+    """Generate opcode enumerations."""
+    fmt = srcgen.Formatter()
+    fmt.line('enum Opcode {')
+    fmt.indent_push()
+    for g in groups:
+        for i in g.instructions:
+            fmt.line(i.camel_name + ',')
+    fmt.indent_pop()
+    fmt.line('}')
+    fmt.update_file('opcodes.rs', out_dir)
+
+def generate(targets, out_dir):
+    groups = collect_instr_groups(targets)
+    gen_opcodes(groups, out_dir)
diff --git a/meta/srcgen.py b/meta/srcgen.py
new file mode 100644
index 0000000000..9778e2c518
--- /dev/null
+++ b/meta/srcgen.py
@@ -0,0 +1,73 @@
+"""
+Source code generator.
+
+The `srcgen` module contains generic helper routines and classes for generating
+source code.
+
+"""
+
+import sys
+import os
+
+class Formatter(object):
+    """
+    Source code formatter class.
+
+    - Collect source code to be written to a file.
+    - Keep track of indentation.
+
+    Indentation example:
+
+        >>> f = Formatter()
+        >>> f.line('Hello line 1')
+        >>> f.writelines()
+        Hello line 1
+        >>> f.indent_push()
+        >>> f.comment('Nested comment')
+        >>> f.indent_pop()
+        >>> f.line('Back again')
+        >>> f.writelines()
+        Hello line 1
+          // Nested comment
+        Back again
+
+    """
+
+    shiftwidth = 2
+
+    def __init__(self):
+        self.indent = ''
+        self.lines = []
+
+    def indent_push(self):
+        """Increase current indentation level by one."""
+        self.indent += ' ' * self.shiftwidth
+
+    def indent_pop(self):
+        """Decrease indentation by one level."""
+        assert self.indent != '', 'Already at top level indentation'
+        self.indent = self.indent[0:-self.shiftwidth]
+
+    def line(self, s):
+        """And an indented line."""
+        self.lines.append('{}{}\n'.format(self.indent, s))
+
+    def writelines(self, f=None):
+        """Write all lines to `f`."""
+        if not f:
+            f = sys.stdout
+        f.writelines(self.lines)
+
+    def update_file(self, filename, directory):
+        if directory is not None:
+            filename = os.path.join(directory, filename)
+        with open(filename, 'w') as f:
+            self.writelines(f)
+
+    def comment(self, s):
+        """Add a comment line."""
+        self.line('// ' + s)
+
+if __name__ == "__main__":
+    import doctest
+    doctest.testmod()