Add more "extended opcode" structure to libdex.

Although we don't yet generate any of the extended opcodes, this
change makes it a bit easier to add them.

In particular, we now differentiate between the raw opcode in a code
unit and an associated "packed opcode number." The packed opcode space
is densely populated in the range 0x000-0x1ff (though there will still
be a few unused slots), whereas the raw opcode values are sparse
throughout the range 0x0000-0xffff.

The OpCode enum is redefined/clarified to have packed, not sparse,
opcode values.

Change-Id: Ie3208a258648fbf044d344646f66c49ad24c31b2

1 files changed, 11 insertions, 0 deletions

diff --git a/opcode-gen/opcode-gen b/opcode-gen/opcode-gen
index 8a99134ad..64011ce83 100755
--- a/opcode-gen/opcode-gen
+++ b/opcode-gen/opcode-gen
@@ -480,6 +480,17 @@ function flagsToC(f, parts, result, i) {
     return result;
 }
 
+# Given a packed opcode, returns the raw (unpacked) opcode value.
+function unpackOpcode(idx) {
+    # Note: This must be the inverse of the corresponding code in
+    # libdex/OpCode.h.
+    if (idx <= 0xff) {
+        return idx;
+    } else {
+        return (idx << 8) | 0xff;
+    }
+}
+
 # Returns true if the given opcode (by index) is an "optimized" opcode.
 function isOptimized(idx, parts, f) {
     # locals: parts, f