62 lines
2.5 KiB
Racket
62 lines
2.5 KiB
Racket
#lang racket/base
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Here's the idea:
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- Take a module's bytecode
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- Recursively get all the bytecode for modules that the target requires
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- After reading it, prune everything that isn't at phase 0 (the runtime phase)
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- Now that we have all the modules, the next step is to merge them into a single
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module
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-- Although actually we collapse them into the top-level, not a module
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- To do that, we iterate through all the modules doing two things as we go:
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-- Incrementing all the global variable references by all the references in all
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the modules
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--- So if A has 5, then B's start at index 5 and so on
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-- Replacing module variable references with the actual global variables
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corresponding to those variables
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--- So if A's variable 'x' is in global slot 4, then if B refers to it, it
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directly uses slot 4, rather than a module-variable slot
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- At that point we have all the module code in a single top-level, but many
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toplevels won't be used because a library function isn't really used
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- So, we do a "garbage collection" on elements of the prefix
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- First, we create a dependency graph of all toplevels and the initial scope
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- Then, we do a DFS on the initial scope and keep all those toplevels, throwing
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away the construction of everything else
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[XXX: This may be broken because of side-effects.]
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- Now we have a small amount code, but because we want to go back to source,
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we need to fix it up a bit; because different modules may've used the same
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names
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- So, we do alpha-renaming, but it's easy because names are only used in the
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compilation-top prefix structure
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[TODO]
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- Next, we decompile
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- Then, it will pay to do dead code elimination and inlining, etc.
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|#
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(require racket/cmdline
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racket/set
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raco/command-name
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"main.rkt")
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(let ([output-file (make-parameter #f)])
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(command-line #:program (short-program+command-name)
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#:multi
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[("-e" "--exclude-modules") path "Exclude <path> from flattening"
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(current-excluded-modules (set-add (current-excluded-modules) path))]
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#:once-each
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[("-o") dest-filename "Write output as <dest-filename>"
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(output-file (string->path dest-filename))]
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[("-g" "--garbage-collect") "Garbage-collect final module (unsound)"
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(garbage-collect-toplevels-enabled #t)]
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#:args (filename)
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(demodularize filename (output-file))))
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(module test racket/base)
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