decodetree: Allow grouping of overlapping patterns

Backports commit 0eff2df4a2ce677230119440f7eb057acffad5eb from qemu

qemu/scripts/decodetree.py

@@ -163,6 +163,7 @@ fields = {}
 arguments = {}
 formats = {}
 patterns = []
+allpatterns = []
 
 translate_prefix = 'trans'
 translate_scope = 'static '
@@ -434,13 +435,7 @@ class General:
         self.fields = flds
 
     def __str__(self):
-        r = self.name
+        return self.name + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
-        if self.base:
-            r = r + ' ' + self.base.name
-        else:
-            r = r + ' ' + str(self.fields)
-        r = r + ' ' + str_match_bits(self.fixedbits, self.fixedmask)
-        return r
 
     def str1(self, i):
         return str_indent(i) + self.__str__()
@@ -487,6 +482,47 @@ class Pattern(General):
 # end Pattern
 
 
+class MultiPattern(General):
+    """Class representing an overlapping set of instruction patterns"""
+
+    def __init__(self, lineno, pats, fixb, fixm, udfm):
+        self.file = input_file
+        self.lineno = lineno
+        self.pats = pats
+        self.base = None
+        self.fixedbits = fixb
+        self.fixedmask = fixm
+        self.undefmask = udfm
+
+    def __str__(self):
+        r = "{"
+        for p in self.pats:
+           r = r + ' ' + str(p)
+        return r + "}"
+
+    def output_decl(self):
+        for p in self.pats:
+            p.output_decl()
+
+    def output_code(self, i, extracted, outerbits, outermask):
+        global translate_prefix
+        ind = str_indent(i)
+        for p in self.pats:
+            if outermask != p.fixedmask:
+                innermask = p.fixedmask & ~outermask
+                innerbits = p.fixedbits & ~outermask
+                output(ind, 'if ((insn & ',
+                       '0x{0:08x}) == 0x{1:08x}'.format(innermask, innerbits),
+                       ') {\n')
+                output(ind, '    /* ',
+                       str_match_bits(p.fixedbits, p.fixedmask), ' */\n')
+                p.output_code(i + 4, extracted, p.fixedbits, p.fixedmask)
+                output(ind, '}\n')
+            else:
+                p.output_code(i, extracted, p.fixedbits, p.fixedmask)
+#end MultiPattern
+
+
 def parse_field(lineno, name, toks):
     """Parse one instruction field from TOKS at LINENO"""
     global fields
@@ -639,6 +675,7 @@ def parse_generic(lineno, is_format, name, toks):
     global arguments
     global formats
     global patterns
+    global allpatterns
     global re_ident
     global insnwidth
     global insnmask
@@ -783,6 +820,7 @@ def parse_generic(lineno, is_format, name, toks):
         pat = Pattern(name, lineno, fmt, fixedbits, fixedmask,
                       undefmask, fieldmask, flds)
         patterns.append(pat)
+        allpatterns.append(pat)
 
     # Validate the masks that we have assembled.
     if fieldmask & fixedmask:
@@ -802,16 +840,67 @@ def parse_generic(lineno, is_format, name, toks):
 # end parse_general
 
 
+def build_multi_pattern(lineno, pats):
+    """Validate the Patterns going into a MultiPattern."""
+    global patterns
+    global insnmask
+
+    if len(pats) < 2:
+        error(lineno, 'less than two patterns within braces')
+
+    fixedmask = insnmask
+    undefmask = insnmask
+
+    # Collect fixed/undefmask for all of the children.
+    # Move the defining lineno back to that of the first child.
+    for p in pats:
+        fixedmask &= p.fixedmask
+        undefmask &= p.undefmask
+        if p.lineno < lineno:
+            lineno = p.lineno
+
+    repeat = True
+    while repeat:
+        if fixedmask == 0:
+            error(lineno, 'no overlap in patterns within braces')
+        fixedbits = None
+        for p in pats:
+            thisbits = p.fixedbits & fixedmask
+            if fixedbits is None:
+                fixedbits = thisbits
+            elif fixedbits != thisbits:
+                fixedmask &= ~(fixedbits ^ thisbits)
+                break
+        else:
+            repeat = False
+
+    mp = MultiPattern(lineno, pats, fixedbits, fixedmask, undefmask)
+    patterns.append(mp)
+# end build_multi_pattern
+
+
 def parse_file(f):
     """Parse all of the patterns within a file"""
 
+    global patterns
+
     # Read all of the lines of the file.  Concatenate lines
     # ending in backslash; discard empty lines and comments.
     toks = []
     lineno = 0
+    nesting = 0
+    saved_pats = []
+
     for line in f:
         lineno += 1
 
+        # Expand and strip spaces, to find indent.
+        line = line.rstrip()
+        line = line.expandtabs()
+        len1 = len(line)
+        line = line.lstrip()
+        len2 = len(line)
+
         # Discard comments
         end = line.find('#')
         if end >= 0:
@@ -821,10 +910,18 @@ def parse_file(f):
         if len(toks) != 0:
             # Next line after continuation
             toks.extend(t)
-        elif len(t) == 0:
-            # Empty line
-            continue
         else:
+            # Allow completely blank lines.
+            if len1 == 0:
+                continue
+            indent = len1 - len2
+            # Empty line due to comment.
+            if len(t) == 0:
+                # Indentation must be correct, even for comment lines.
+                if indent != nesting:
+                    error(lineno, 'indentation ', indent, ' != ', nesting)
+                continue
+            start_lineno = lineno
             toks = t
 
         # Continuation?
@@ -832,21 +929,47 @@ def parse_file(f):
             toks.pop()
             continue
 
-        if len(toks) < 2:
-            error(lineno, 'short line')
-
         name = toks[0]
         del toks[0]
 
+        # End nesting?
+        if name == '}':
+            if nesting == 0:
+                error(start_lineno, 'mismatched close brace')
+            if len(toks) != 0:
+                error(start_lineno, 'extra tokens after close brace')
+            nesting -= 2
+            if indent != nesting:
+                error(start_lineno, 'indentation ', indent, ' != ', nesting)
+            pats = patterns
+            patterns = saved_pats.pop()
+            build_multi_pattern(lineno, pats)
+            toks = []
+            continue
+
+        # Everything else should have current indentation.
+        if indent != nesting:
+            error(start_lineno, 'indentation ', indent, ' != ', nesting)
+
+        # Start nesting?
+        if name == '{':
+            if len(toks) != 0:
+                error(start_lineno, 'extra tokens after open brace')
+            saved_pats.append(patterns)
+            patterns = []
+            nesting += 2
+            toks = []
+            continue
+
         # Determine the type of object needing to be parsed.
         if name[0] == '%':
-            parse_field(lineno, name[1:], toks)
+            parse_field(start_lineno, name[1:], toks)
         elif name[0] == '&':
-            parse_arguments(lineno, name[1:], toks)
+            parse_arguments(start_lineno, name[1:], toks)
         elif name[0] == '@':
-            parse_generic(lineno, True, name[1:], toks)
+            parse_generic(start_lineno, True, name[1:], toks)
         else:
-            parse_generic(lineno, False, name, toks)
+            parse_generic(start_lineno, False, name, toks)
         toks = []
 # end parse_file
 
@@ -923,11 +1046,10 @@ def build_tree(pats, outerbits, outermask):
         innermask &= i.fixedmask
 
     if innermask == 0:
-        pnames = []
+        text = 'overlapping patterns:'
         for p in pats:
-            pnames.append(p.name + ':' + p.file + ':' + str(p.lineno))
+            text += '\n' + p.file + ':' + str(p.lineno) + ': ' + str(p)
-        error_with_file(pats[0].file, pats[0].lineno,
+        error_with_file(pats[0].file, pats[0].lineno, text)
-                        'overlapping patterns:', pnames)
 
     fullmask = outermask | innermask
 
@@ -980,6 +1102,7 @@ def main():
     global arguments
     global formats
     global patterns
+    global allpatterns
     global translate_scope
     global translate_prefix
     global output_fd
@@ -1041,7 +1164,7 @@ def main():
     # Make sure that the argument sets are the same, and declare the
     # function only once.
     out_pats = {}
-    for i in patterns:
+    for i in allpatterns:
         if i.name in out_pats:
             p = out_pats[i.name]
             if i.base.base != p.base.base: