-(* README
- * Author: Frank Pfenning <fp@cs.cmu.edu>
- *)
-
------------------------------------------------------------------------
-Welcome to 15-411 F08!
------------------------------------------------------------------------
-
-This is some starter code for the L1 compiler you have to build for
-the Lab1. It contains a lexer, parser, translator, and even a code
-generator, except that the code generator creates pseudo assembly
-language with fictitious instructions and an unlimited number of
-registers. We took some care to use good style (according to the
-instructor); you may consider this a model for your own coding. Feel
-free to modify any and all of this code as you see fit.
-
-Bug reports to the instructor Frank Pfenning <fp@cs.cmu.edu> are
-particularly welcome and will be noted in the extra credit category.
-
------------------------------------------------------------------------
-SML Notes
------------------------------------------------------------------------
-There are many different compilers for SML, perhaps the most
-popular ones are
-
- SML/NJ -- http://www.smlnj.org/
- MLton -- http://www.mlton.org/
- Poly/ML -- http://www.polyml.org/
-
-In this class we will be using SML/NJ v110.59. Please make sure your
-code compiles under specifically this version on the lab machines
-where it is the default and can be invoked simply with "sml" in a
-shell.
-
-If you develop your implementation on other machines, similar versions
-of SML/NJ are likely to be compatible, but you should certainly check
-your code on the lab machines.
-
-For (almost universal) Standard Basis Libraries, see
-http://www.standardml.org/Basis/index.html. Further resources, such
-as documentation for ML-Lex and ML-Yacc, and documentation for the SML/NJ
-specific libraries which are used in the starter code, can be found at
-
- http://www.cs.cmu.edu/~fp/courses/15411-f08/resources.html
-
-------------------------------------------------------------------------
-Source Files
-------------------------------------------------------------------------
-The following are the source files for the L1 compiler
-
-README -- this file
-
-Makefile -- makefile for the compiler
- For a quick test
-
- % make l1c (generates file bin/l1c.heap.<os-tag>)
- % bin/l1c --verbose ../tests/test1.c
-
- should generate ../tests/test1.s in pseudo assembly
-
- % make clean (removes generated files)
- % make TAGS (creates file TAGS, for Emacs tags commands)
-
-compile-l1c.sml -- SML commands that will create bin/l1c.heap.<os-tag>
-bin/l1c -- the script that will run the exported SML heap
-
-sources.cm -- lists all source files, including libraries,
- and lexer and grammar specifications
- For a quick test
-
- % sml
- - CM.make "sources.cm";
- - Top.test "--verbose ../tests/test1.c";
-
- should generate ../tests/test1.s in pseudo assembly
-
-parse/ast.sml -- definition and printer for abstract syntax trees (AST's)
-parse/l1.lex -- L1 lexer
-parse/l1.grm -- L1 grammar
-parse/parse.sml -- L1 parser
-parse/parsestate.sml -- L1 parser support for error messages
-
-type/typechecker.sml -- (trivial) type-checker for AST
-
-trans/temp.sml -- functions to generate and track temp's
-trans/tree.sml -- definition and pretty printer for IR trees
-trans/trans.sml -- translation from AST to IR trees
-
-codegen/assem.sml -- pseudo assembly format for this starter code
-codegen/codegen.sml -- pseudo code generator
-
-util/errormsg.sml -- error message utilities
-util/flag.sml -- library for defining flags
-util/mark.sml -- library for tracking source file positions
-util/safe-io.sml -- I/O utilities
-util/symbol.sml -- symbol table library
-util/word32.sml -- machine word utilities for two's complement interpretation
-
-top/top.sml -- top level function for export to binary and testing
-
-------------------------------------------------------------------------
-Debugging Hints
-------------------------------------------------------------------------
-You can use
-
- - Top.test "--verbose --dump-ast --dump-ir --dump-assem file.l1";
-
-to print information from all the phases of the current compiler.
-
-If you want to see the internal representations, you can call directly
-on SML's top level:
-
- - val ast = Parse.parse "file.l1";
- - val ir = Trans.translate ast;
- - val assem = Codegen.codgen ir;
-
-This will use SML's internal printing function to print the data
-structures. However, not everything will show.
-
-"-" means that the type is opaque. Sometimes you can replace an opaque
- signature ascription ":>" with a transparent one ":" to see the info.
- For reasons of general hygiene, however, you should change it back
- before handing in.
-
-"#" means that the printing depth is exceeded. Use
-
- - Control.Print.printDepth := 100;
-
- to increase the depth if you need to see more.
-
-"..." means that the printing length is exceeded. Use
-
- - Control.Print.printLength := 1000;
-
- to increase the length if you need to see more.
-
-------------------------------------------------------------------------
-Library Hints
-------------------------------------------------------------------------
-See util/symbol.sml for some uses of libraries provided with SML/NJ
-(and some other SML implementations). BinaryMapFn and
-BinarySetFn are likely of general use. To see their interface,
-you can check http://www.smlnj.org/doc/smlnj-lib/Manual/toc.html.
-I found binary maps and binary sets to be occasionally helpful.
+README
+------
+
+This compiler is a big long chain of modules that transform l4 code into
+x86_64 assembly.
+
+Here is a breakdown of the modules and changes from l3:
+
+ * The parser. The parser was mainly brought in from lab 3, and mainly
+ just a straight-forward extension of the l3 parser. We changed asops,
+ since they now side-effect and need special properties. We also added
+ dereferences, arrays, other nice things.
+
+ * AST utilities. Some of those now exist to make common operations on raw
+ AST structures less painful.
+
+ * The typechecker. The typechecker was significantly revamped. A
+ 'typeof' function was added that did most of the typechecking work;
+ the rest was relatively trivial compared to typeof. There were many
+ annoying things other than typeof, but typeof was the most interesting
+ to comment on.
+
+ * The translator was extended with support for sizing up structs. It now
+ is smarter about translating asops. A MEMORY thingo was added to the
+ Tree, as was ALLOC.
+
+ * The x86/munch modules were extended with support for multiple operand
+ sizes. This was done in a fashion of extreme type A, and needs to be
+ blasted before the next lab, for it is worthless, terrible, awful, ... A
+ major falling-down of this compiler is that it passes size information
+ around in no less than 235784 different fashions, and the translation
+ between each has caused us no end of grief. If we had time to rewrite
+ it instead of firefighting broken tests, uh... we would. Many of our
+ optimizations from last lab needed to be commented out because of this
+ temporary sizing sadness.
+
+ * The liveness analyzer was mainly unchanged, but for a few rules.
+
+ * The grapher was fully unchanged. Nice.
+
+ * The color orderer was fully unchanged. Nice.
+
+ * The coloring module was fully unchanged. Nice.
+
+ * The solidifier was modified to deal with the fact that certain things
+ could not be accessed directly. It, too, has become an unmitigated
+ disaster. It must deal with all 875847384 of the sizes, and I am sad
+ about this.
+
+ * The peepholer lost one form of fail and loss sizing.
+
+ * The stringifier is of no interest to you, for it does real things that
+ interact with the real world, and that is not of interest to people who
+ write in ML.
+
+ * Our internal representation of x86 assembly was changed. In particular,
+ conditional sets and jumps are now SETcc of cc * oper and Jcc of cc *
+ oper, instead of a separate SET or J for each condition code. This
+ simplifies other parts of the code as well.
+
+We believe that it is fully functional. We generate correct code whenever we
+are supposed to, and we pass every test that we can lay our hands on
+(including all of l2, and one of ours that killed the reference compiler).
+Of course, our last bug was caught by only one failing test, so...
\ No newline at end of file