;;; Guile bytecode assembler
;;; Copyright (C) 2001, 2009, 2010, 2012, 2013, 2014 Free Software Foundation, Inc.
;;;
;;; This library is free software; you can redistribute it and/or
;;; modify it under the terms of the GNU Lesser General Public
;;; License as published by the Free Software Foundation; either
;;; version 3 of the License, or (at your option) any later version.
;;;
;;; This library is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this library; if not, write to the Free Software
;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;; Commentary:
;;;
;;; This module implements an assembler that creates an ELF image from
;;; bytecode assembly and macro-assembly. The input can be given in
;;; s-expression form, like ((OP ARG ...) ...). Internally there is a
;;; procedural interface, the emit-OP procedures, but that is not
;;; currently exported.
;;;
;;; "Primitive instructions" correspond to VM operations. Assemblers
;;; for primitive instructions are generated programmatically from
;;; (instruction-list), which itself is derived from the VM sources.
;;; There are also "macro-instructions" like "label" or "load-constant"
;;; that expand to 0 or more primitive instructions.
;;;
;;; The assembler also handles some higher-level tasks, like creating
;;; the symbol table, other metadata sections, creating a constant table
;;; for the whole compilation unit, and writing the dynamic section of
;;; the ELF file along with the appropriate initialization routines.
;;;
;;; Most compilers will want to use the trio of make-assembler,
;;; emit-text, and link-assembly. That will result in the creation of
;;; an ELF image as a bytevector, which can then be loaded using
;;; load-thunk-from-memory, or written to disk as a .go file.
;;;
;;; Code:
(define-module (system vm assembler)
#:use-module (system base target)
#:use-module (system vm dwarf)
#:use-module (system vm elf)
#:use-module (system vm linker)
#:use-module (language bytecode)
#:use-module (rnrs bytevectors)
#:use-module (ice-9 binary-ports)
#:use-module (ice-9 vlist)
#:use-module (ice-9 match)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-4)
#:use-module (srfi srfi-9)
#:use-module (srfi srfi-11)
#:export (make-assembler
emit-text
link-assembly))
;;; Bytecode consists of 32-bit units, often subdivided in some way.
;;; These helpers create one 32-bit unit from multiple components.
(define-inlinable (pack-u8-u24 x y)
(unless (<= 0 x 255)
(error "out of range" x))
(logior x (ash y 8)))
(define-inlinable (pack-u8-s24 x y)
(unless (<= 0 x 255)
(error "out of range" x))
(logior x (ash (cond
((< 0 (- y) #x800000)
(+ y #x1000000))
((<= 0 y #xffffff)
y)
(else (error "out of range" y)))
8)))
(define-inlinable (pack-u1-u7-u24 x y z)
(unless (<= 0 x 1)
(error "out of range" x))
(unless (<= 0 y 127)
(error "out of range" y))
(logior x (ash y 1) (ash z 8)))
(define-inlinable (pack-u8-u12-u12 x y z)
(unless (<= 0 x 255)
(error "out of range" x))
(unless (<= 0 y 4095)
(error "out of range" y))
(logior x (ash y 8) (ash z 20)))
(define-inlinable (pack-u8-u8-u16 x y z)
(unless (<= 0 x 255)
(error "out of range" x))
(unless (<= 0 y 255)
(error "out of range" y))
(logior x (ash y 8) (ash z 16)))
(define-inlinable (pack-u8-u8-u8-u8 x y z w)
(unless (<= 0 x 255)
(error "out of range" x))
(unless (<= 0 y 255)
(error "out of range" y))
(unless (<= 0 z 255)
(error "out of range" z))
(logior x (ash y 8) (ash z 16) (ash w 24)))
(define-syntax pack-flags
(syntax-rules ()
;; Add clauses as needed.
((pack-flags f1 f2) (logior (if f1 (ash 1 0) 0)
(if f2 (ash 2 0) 0)))))
;;; Helpers to read and write 32-bit units in a buffer.
(define-syntax-rule (u32-ref buf n)
(bytevector-u32-native-ref buf (* n 4)))
(define-syntax-rule (u32-set! buf n val)
(bytevector-u32-native-set! buf (* n 4) val))
(define-syntax-rule (s32-ref buf n)
(bytevector-s32-native-ref buf (* n 4)))
(define-syntax-rule (s32-set! buf n val)
(bytevector-s32-native-set! buf (* n 4) val))
;;; A entry collects metadata for one procedure. Procedures are
;;; written as contiguous ranges of bytecode.
;;;
(define-syntax-rule (assert-match arg pattern kind)
(let ((x arg))
(unless (match x (pattern #t) (_ #f))
(error (string-append "expected " kind) x))))
(define-record-type
(%make-meta label properties low-pc high-pc arities)
meta?
(label meta-label)
(properties meta-properties set-meta-properties!)
(low-pc meta-low-pc)
(high-pc meta-high-pc set-meta-high-pc!)
(arities meta-arities set-meta-arities!))
(define (make-meta label properties low-pc)
(assert-match label (? symbol?) "symbol")
(assert-match properties (((? symbol?) . _) ...) "alist with symbolic keys")
(%make-meta label properties low-pc #f '()))
(define (meta-name meta)
(assq-ref (meta-properties meta) 'name))
;; Metadata for one .
(define-record-type
(make-arity req opt rest kw-indices allow-other-keys?
low-pc high-pc)
arity?
(req arity-req)
(opt arity-opt)
(rest arity-rest)
(kw-indices arity-kw-indices)
(allow-other-keys? arity-allow-other-keys?)
(low-pc arity-low-pc)
(high-pc arity-high-pc set-arity-high-pc!))
(define-syntax *block-size* (identifier-syntax 32))
;;; An assembler collects all of the words emitted during assembly, and
;;; also maintains ancillary information such as the constant table, a
;;; relocation list, and so on.
;;;
;;; Bytecode consists of 32-bit units. We emit bytecode using native
;;; endianness. If we're targeting a foreign endianness, we byte-swap
;;; the bytevector as a whole instead of conditionalizing each access.
;;;
(define-record-type
(make-asm cur idx start prev written
labels relocs
word-size endianness
constants inits
shstrtab next-section-number
meta sources
dead-slot-maps)
asm?
;; We write bytecode into what is logically a growable vector,
;; implemented as a list of blocks. asm-cur is the current block, and
;; asm-idx is the current index into that block, in 32-bit units.
;;
(cur asm-cur set-asm-cur!)
(idx asm-idx set-asm-idx!)
;; asm-start is an absolute position, indicating the offset of the
;; beginning of an instruction (in u32 units). It is updated after
;; writing all the words for one primitive instruction. It models the
;; position of the instruction pointer during execution, given that
;; the VM updates the IP only at the end of executing the instruction,
;; and is thus useful for computing offsets between two points in a
;; program.
;;
(start asm-start set-asm-start!)
;; The list of previously written blocks.
;;
(prev asm-prev set-asm-prev!)
;; The number of u32 words written in asm-prev, which is the same as
;; the offset of the current block.
;;
(written asm-written set-asm-written!)
;; An alist of symbol -> position pairs, indicating the labels defined
;; in this compilation unit.
;;
(labels asm-labels set-asm-labels!)
;; A list of relocations needed by the program text. We use an
;; internal representation for relocations, and handle textualn
;; relative relocations in the assembler. Other kinds of relocations
;; are later reified as linker relocations and resolved by the linker.
;;
(relocs asm-relocs set-asm-relocs!)
;; Target information.
;;
(word-size asm-word-size)
(endianness asm-endianness)
;; The constant table, as a vhash of object -> label. All constants
;; get de-duplicated and written into separate sections -- either the
;; .rodata section, for read-only data, or .data, for constants that
;; need initialization at load-time (like symbols). Constants can
;; depend on other constants (e.g. a symbol depending on a stringbuf),
;; so order in this table is important.
;;
(constants asm-constants set-asm-constants!)
;; A list of instructions needed to initialize the constants. Will
;; run in a thunk with 2 local variables.
;;
(inits asm-inits set-asm-inits!)
;; The shstrtab, for section names.
;;
(shstrtab asm-shstrtab set-asm-shstrtab!)
;; The section number for the next section to be written.
;;
(next-section-number asm-next-section-number set-asm-next-section-number!)
;; A list of , corresponding to procedure metadata.
;;
(meta asm-meta set-asm-meta!)
;; A list of (pos . source) pairs, indicating source information. POS
;; is relative to the beginning of the text section, and SOURCE is in
;; the same format that source-properties returns.
;;
(sources asm-sources set-asm-sources!)
;; A list of (pos . dead-slot-map) pairs, indicating dead slot maps.
;; POS is relative to the beginning of the text section.
;; DEAD-SLOT-MAP is a bitfield of slots that are dead at call sites,
;; as an integer.
;;
(dead-slot-maps asm-dead-slot-maps set-asm-dead-slot-maps!))
(define-inlinable (fresh-block)
(make-u32vector *block-size*))
(define* (make-assembler #:key (word-size (target-word-size))
(endianness (target-endianness)))
"Create an assembler for a given target @var{word-size} and
@var{endianness}, falling back to appropriate values for the configured
target."
(make-asm (fresh-block) 0 0 '() 0
(make-hash-table) '()
word-size endianness
vlist-null '()
(make-string-table) 1
'() '() '()))
(define (intern-section-name! asm string)
"Add a string to the section name table (shstrtab)."
(string-table-intern! (asm-shstrtab asm) string))
(define-inlinable (asm-pos asm)
"The offset of the next word to be written into the code buffer, in
32-bit units."
(+ (asm-idx asm) (asm-written asm)))
(define (allocate-new-block asm)
"Close off the current block, and arrange for the next word to be
written to a fresh block."
(let ((new (fresh-block)))
(set-asm-prev! asm (cons (asm-cur asm) (asm-prev asm)))
(set-asm-written! asm (asm-pos asm))
(set-asm-cur! asm new)
(set-asm-idx! asm 0)))
(define-inlinable (emit asm u32)
"Emit one 32-bit word into the instruction stream. Assumes that there
is space for the word, and ensures that there is space for the next
word."
(u32-set! (asm-cur asm) (asm-idx asm) u32)
(set-asm-idx! asm (1+ (asm-idx asm)))
(if (= (asm-idx asm) *block-size*)
(allocate-new-block asm)))
(define-inlinable (make-reloc type label base word)
"Make an internal relocation of type @var{type} referencing symbol
@var{label}, @var{word} words after position @var{start}. @var{type}
may be x8-s24, indicating a 24-bit relative label reference that can be
fixed up by the assembler, or s32, indicating a 32-bit relative
reference that needs to be fixed up by the linker."
(list type label base word))
(define-inlinable (reset-asm-start! asm)
"Reset the asm-start after writing the words for one instruction."
(set-asm-start! asm (asm-pos asm)))
(define (record-label-reference asm label)
"Record an x8-s24 local label reference. This value will get patched
up later by the assembler."
(let* ((start (asm-start asm))
(pos (asm-pos asm))
(reloc (make-reloc 'x8-s24 label start (- pos start))))
(set-asm-relocs! asm (cons reloc (asm-relocs asm)))))
(define* (record-far-label-reference asm label #:optional (offset 0))
"Record an s32 far label reference. This value will get patched up
later by the linker."
(let* ((start (- (asm-start asm) offset))
(pos (asm-pos asm))
(reloc (make-reloc 's32 label start (- pos start))))
(set-asm-relocs! asm (cons reloc (asm-relocs asm)))))
;;;
;;; Primitive assemblers are defined by expanding `assembler' for each
;;; opcode in `(instruction-list)'.
;;;
(eval-when (expand compile load eval)
(define (id-append ctx a b)
(datum->syntax ctx (symbol-append (syntax->datum a) (syntax->datum b)))))
(define-syntax assembler
(lambda (x)
(define-syntax op-case
(lambda (x)
(syntax-case x ()
((_ asm name ((type arg ...) code ...) clause ...)
#`(if (eq? name 'type)
(with-syntax (((arg ...) (generate-temporaries #'(arg ...))))
#'((arg ...)
code ...))
(op-case asm name clause ...)))
((_ asm name)
#'(error "unmatched name" name)))))
(define (pack-first-word asm opcode type)
(with-syntax ((opcode opcode))
(op-case
asm type
((U8_X24)
(emit asm opcode))
((U8_U24 arg)
(emit asm (pack-u8-u24 opcode arg)))
((U8_L24 label)
(record-label-reference asm label)
(emit asm opcode))
((U8_U8_I16 a imm)
(emit asm (pack-u8-u8-u16 opcode a (object-address imm))))
((U8_U12_U12 a b)
(emit asm (pack-u8-u12-u12 opcode a b)))
((U8_U8_U8_U8 a b c)
(emit asm (pack-u8-u8-u8-u8 opcode a b c))))))
(define (pack-tail-word asm type)
(op-case
asm type
((U8_U24 a b)
(emit asm (pack-u8-u24 a b)))
((U8_L24 a label)
(record-label-reference asm label)
(emit asm a))
((U8_U8_I16 a b imm)
(emit asm (pack-u8-u8-u16 a b (object-address imm))))
((U8_U12_U12 a b)
(emit asm (pack-u8-u12-u12 a b c)))
((U8_U8_U8_U8 a b c d)
(emit asm (pack-u8-u8-u8-u8 a b c d)))
((U32 a)
(emit asm a))
((I32 imm)
(let ((val (object-address imm)))
(unless (zero? (ash val -32))
(error "FIXME: enable truncation of negative fixnums when cross-compiling"))
(emit asm val)))
((A32 imm)
(unless (= (asm-word-size asm) 8)
(error "make-long-immediate unavailable for this target"))
(emit asm (ash (object-address imm) -32))
(emit asm (logand (object-address imm) (1- (ash 1 32)))))
((B32))
((N32 label)
(record-far-label-reference asm label)
(emit asm 0))
((S32 label)
(record-far-label-reference asm label)
(emit asm 0))
((L32 label)
(record-far-label-reference asm label)
(emit asm 0))
((LO32 label offset)
(record-far-label-reference asm label
(* offset (/ (asm-word-size asm) 4)))
(emit asm 0))
((X8_U24 a)
(emit asm (pack-u8-u24 0 a)))
((X8_U12_U12 a b)
(emit asm (pack-u8-u12-u12 0 a b)))
((X8_L24 label)
(record-label-reference asm label)
(emit asm 0))
((B1_X7_L24 a label)
(record-label-reference asm label)
(emit asm (pack-u1-u7-u24 (if a 1 0) 0 0)))
((B1_U7_L24 a b label)
(record-label-reference asm label)
(emit asm (pack-u1-u7-u24 (if a 1 0) b 0)))
((B1_X31 a)
(emit asm (pack-u1-u7-u24 (if a 1 0) 0 0)))
((B1_X7_U24 a b)
(emit asm (pack-u1-u7-u24 (if a 1 0) 0 b)))))
(syntax-case x ()
((_ name opcode word0 word* ...)
(with-syntax ((((formal0 ...)
code0 ...)
(pack-first-word #'asm
(syntax->datum #'opcode)
(syntax->datum #'word0)))
((((formal* ...)
code* ...) ...)
(map (lambda (word) (pack-tail-word #'asm word))
(syntax->datum #'(word* ...)))))
#'(lambda (asm formal0 ... formal* ... ...)
(unless (asm? asm) (error "not an asm"))
code0 ...
code* ... ...
(reset-asm-start! asm)))))))
(define assemblers (make-hash-table))
(define-syntax define-assembler
(lambda (x)
(syntax-case x ()
((_ name opcode kind arg ...)
(with-syntax ((emit (id-append #'name #'emit- #'name)))
#'(begin
(define emit
(let ((emit (assembler name opcode arg ...)))
(hashq-set! assemblers 'name emit)
emit))
(export emit)))))))
(define-syntax visit-opcodes
(lambda (x)
(syntax-case x ()
((visit-opcodes macro arg ...)
(with-syntax (((inst ...)
(map (lambda (x) (datum->syntax #'macro x))
(instruction-list))))
#'(begin
(macro arg ... . inst)
...))))))
(visit-opcodes define-assembler)
(define (emit-text asm instructions)
"Assemble @var{instructions} using the assembler @var{asm}.
@var{instructions} is a sequence of instructions, expressed as a list of
lists. This procedure can be called many times before calling
@code{link-assembly}."
(for-each (lambda (inst)
(apply (or (hashq-ref assemblers (car inst))
(error 'bad-instruction inst))
asm
(cdr inst)))
instructions))
;;;
;;; The constant table records a topologically sorted set of literal
;;; constants used by a program. For example, a pair uses its car and
;;; cdr, a string uses its stringbuf, etc.
;;;
;;; Some things we want to add to the constant table are not actually
;;; Scheme objects: for example, stringbufs, cache cells for toplevel
;;; references, or cache cells for non-closure procedures. For these we
;;; define special record types and add instances of those record types
;;; to the table.
;;;
(define-inlinable (immediate? x)
"Return @code{#t} if @var{x} is immediate, and @code{#f} otherwise."
(not (zero? (logand (object-address x) 6))))
(define-record-type
(make-stringbuf string)
stringbuf?
(string stringbuf-string))
(define-record-type
(make-static-procedure code)
static-procedure?
(code static-procedure-code))
(define-record-type
(make-uniform-vector-backing-store bytes element-size)
uniform-vector-backing-store?
(bytes uniform-vector-backing-store-bytes)
(element-size uniform-vector-backing-store-element-size))
(define-record-type
(make-cache-cell scope key)
cache-cell?
(scope cache-cell-scope)
(key cache-cell-key))
(define (simple-vector? obj)
(and (vector? obj)
(equal? (array-shape obj) (list (list 0 (1- (vector-length obj)))))))
(define (simple-uniform-vector? obj)
(and (array? obj)
(symbol? (array-type obj))
(equal? (array-shape obj) (list (list 0 (1- (array-length obj)))))))
(define (statically-allocatable? x)
"Return @code{#t} if a non-immediate constant can be allocated
statically, and @code{#f} if it would need some kind of runtime
allocation."
(or (pair? x) (string? x) (stringbuf? x) (static-procedure? x) (array? x)))
(define (intern-constant asm obj)
"Add an object to the constant table, and return a label that can be
used to reference it. If the object is already present in the constant
table, its existing label is used directly."
(define (recur obj)
(intern-constant asm obj))
(define (field dst n obj)
(let ((src (recur obj)))
(if src
(if (statically-allocatable? obj)
`((static-patch! ,dst ,n ,src))
`((static-ref 1 ,src)
(static-set! 1 ,dst ,n)))
'())))
(define (intern obj label)
(cond
((pair? obj)
(append (field label 0 (car obj))
(field label 1 (cdr obj))))
((simple-vector? obj)
(let lp ((i 0) (inits '()))
(if (< i (vector-length obj))
(lp (1+ i)
(append-reverse (field label (1+ i) (vector-ref obj i))
inits))
(reverse inits))))
((stringbuf? obj) '())
((static-procedure? obj)
`((static-patch! ,label 1 ,(static-procedure-code obj))))
((cache-cell? obj) '())
((symbol? obj)
`((make-non-immediate 1 ,(recur (symbol->string obj)))
(string->symbol 1 1)
(static-set! 1 ,label 0)))
((string? obj)
`((static-patch! ,label 1 ,(recur (make-stringbuf obj)))))
((keyword? obj)
`((static-ref 1 ,(recur (keyword->symbol obj)))
(symbol->keyword 1 1)
(static-set! 1 ,label 0)))
((number? obj)
`((make-non-immediate 1 ,(recur (number->string obj)))
(string->number 1 1)
(static-set! 1 ,label 0)))
((uniform-vector-backing-store? obj) '())
((simple-uniform-vector? obj)
(let ((width (case (array-type obj)
((vu8 u8 s8) 1)
((u16 s16) 2)
;; Bitvectors are addressed in 32-bit units.
;; Although a complex number is 8 or 16 bytes wide,
;; it should be byteswapped in 4 or 8 byte units.
((u32 s32 f32 c32 b) 4)
((u64 s64 f64 c64) 8)
(else
(error "unhandled array type" obj)))))
`((static-patch! ,label 2
,(recur (make-uniform-vector-backing-store
(uniform-array->bytevector obj)
width))))))
(else
(error "don't know how to intern" obj))))
(cond
((immediate? obj) #f)
((vhash-assoc obj (asm-constants asm)) => cdr)
(else
;; Note that calling intern may mutate asm-constants and
;; asm-constant-inits.
(let* ((label (gensym "constant"))
(inits (intern obj label)))
(set-asm-constants! asm (vhash-cons obj label (asm-constants asm)))
(set-asm-inits! asm (append-reverse inits (asm-inits asm)))
label))))
(define (intern-non-immediate asm obj)
"Intern a non-immediate into the constant table, and return its
label."
(when (immediate? obj)
(error "expected a non-immediate" obj))
(intern-constant asm obj))
(define (intern-cache-cell asm scope key)
"Intern a cache cell into the constant table, and return its label.
If there is already a cache cell with the given scope and key, it is
returned instead."
(intern-constant asm (make-cache-cell scope key)))
;; Return the label of the cell that holds the module for a scope.
(define (intern-module-cache-cell asm scope)
"Intern a cache cell for a module, and return its label."
(intern-cache-cell asm scope #t))
;;;
;;; Macro assemblers bridge the gap between primitive instructions and
;;; some higher-level operations.
;;;
(define-syntax define-macro-assembler
(lambda (x)
(syntax-case x ()
((_ (name arg ...) body body* ...)
(with-syntax ((emit (id-append #'name #'emit- #'name)))
#'(begin
(define emit
(let ((emit (lambda (arg ...) body body* ...)))
(hashq-set! assemblers 'name emit)
emit))
(export emit)))))))
(define-macro-assembler (load-constant asm dst obj)
(cond
((immediate? obj)
(let ((bits (object-address obj)))
(cond
((and (< dst 256) (zero? (ash bits -16)))
(emit-make-short-immediate asm dst obj))
((zero? (ash bits -32))
(emit-make-long-immediate asm dst obj))
(else
(emit-make-long-long-immediate asm dst obj)))))
((statically-allocatable? obj)
(emit-make-non-immediate asm dst (intern-non-immediate asm obj)))
(else
(emit-static-ref asm dst (intern-non-immediate asm obj)))))
(define-macro-assembler (load-static-procedure asm dst label)
(let ((loc (intern-constant asm (make-static-procedure label))))
(emit-make-non-immediate asm dst loc)))
(define-syntax-rule (define-tc7-macro-assembler name tc7)
(define-macro-assembler (name asm slot invert? label)
(emit-br-if-tc7 asm slot invert? tc7 label)))
;; Keep in sync with tags.h. Part of Guile's ABI. Currently unused
;; macro assemblers are commented out. See also
;; *branching-primcall-arities* in (language cps primitives), the set of
;; macro-instructions in assembly.scm, and
;; disassembler.scm:code-annotation.
;;
;; FIXME: Define all tc7 values in Scheme in one place, derived from
;; tags.h.
(define-tc7-macro-assembler br-if-symbol 5)
(define-tc7-macro-assembler br-if-variable 7)
(define-tc7-macro-assembler br-if-vector 13)
;(define-tc7-macro-assembler br-if-weak-vector 13)
(define-tc7-macro-assembler br-if-string 21)
;(define-tc7-macro-assembler br-if-heap-number 23)
;(define-tc7-macro-assembler br-if-stringbuf 39)
(define-tc7-macro-assembler br-if-bytevector 77)
;(define-tc7-macro-assembler br-if-pointer 31)
;(define-tc7-macro-assembler br-if-hashtable 29)
;(define-tc7-macro-assembler br-if-fluid 37)
;(define-tc7-macro-assembler br-if-dynamic-state 45)
;(define-tc7-macro-assembler br-if-frame 47)
;(define-tc7-macro-assembler br-if-vm 55)
;(define-tc7-macro-assembler br-if-vm-cont 71)
;(define-tc7-macro-assembler br-if-rtl-program 69)
;(define-tc7-macro-assembler br-if-weak-set 85)
;(define-tc7-macro-assembler br-if-weak-table 87)
;(define-tc7-macro-assembler br-if-array 93)
(define-tc7-macro-assembler br-if-bitvector 95)
;(define-tc7-macro-assembler br-if-port 125)
;(define-tc7-macro-assembler br-if-smob 127)
(define-macro-assembler (begin-program asm label properties)
(emit-label asm label)
(let ((meta (make-meta label properties (asm-start asm))))
(set-asm-meta! asm (cons meta (asm-meta asm)))))
(define-macro-assembler (end-program asm)
(let ((meta (car (asm-meta asm))))
(set-meta-high-pc! meta (asm-start asm))
(set-meta-arities! meta (reverse (meta-arities meta)))))
(define-macro-assembler (begin-standard-arity asm req nlocals alternate)
(emit-begin-opt-arity asm req '() #f nlocals alternate))
(define-macro-assembler (begin-opt-arity asm req opt rest nlocals alternate)
(emit-begin-kw-arity asm req opt rest '() #f nlocals alternate))
(define-macro-assembler (begin-kw-arity asm req opt rest kw-indices
allow-other-keys? nlocals alternate)
(assert-match req ((? symbol?) ...) "list of symbols")
(assert-match opt ((? symbol?) ...) "list of symbols")
(assert-match rest (or #f (? symbol?)) "#f or symbol")
(assert-match kw-indices (((? keyword?) . (? integer?)) ...)
"alist of keyword -> integer")
(assert-match allow-other-keys? (? boolean?) "boolean")
(assert-match nlocals (? integer?) "integer")
(assert-match alternate (or #f (? symbol?)) "#f or symbol")
(let* ((meta (car (asm-meta asm)))
(arity (make-arity req opt rest kw-indices allow-other-keys?
(asm-start asm) #f))
;; The procedure itself is in slot 0, in the standard calling
;; convention. For procedure prologues, nreq includes the
;; procedure, so here we add 1.
(nreq (1+ (length req)))
(nopt (length opt))
(rest? (->bool rest)))
(set-meta-arities! meta (cons arity (meta-arities meta)))
(cond
((or allow-other-keys? (pair? kw-indices))
(emit-kw-prelude asm nreq nopt rest? kw-indices allow-other-keys?
nlocals alternate))
((or rest? (pair? opt))
(emit-opt-prelude asm nreq nopt rest? nlocals alternate))
(else
(emit-standard-prelude asm nreq nlocals alternate)))))
(define-macro-assembler (end-arity asm)
(let ((arity (car (meta-arities (car (asm-meta asm))))))
(set-arity-high-pc! arity (asm-start asm))))
(define-macro-assembler (standard-prelude asm nreq nlocals alternate)
(cond
(alternate
(emit-br-if-nargs-ne asm nreq alternate)
(emit-alloc-frame asm nlocals))
((and (< nreq (ash 1 12)) (< (- nlocals nreq) (ash 1 12)))
(emit-assert-nargs-ee/locals asm nreq (- nlocals nreq)))
(else
(emit-assert-nargs-ee asm nreq)
(emit-alloc-frame asm nlocals))))
(define-macro-assembler (opt-prelude asm nreq nopt rest? nlocals alternate)
(if alternate
(emit-br-if-nargs-lt asm nreq alternate)
(emit-assert-nargs-ge asm nreq))
(cond
(rest?
(emit-bind-rest asm (+ nreq nopt)))
(alternate
(emit-br-if-nargs-gt asm (+ nreq nopt) alternate))
(else
(emit-assert-nargs-le asm (+ nreq nopt))))
(emit-alloc-frame asm nlocals))
(define-macro-assembler (kw-prelude asm nreq nopt rest? kw-indices
allow-other-keys? nlocals alternate)
(if alternate
(begin
(emit-br-if-nargs-lt asm nreq alternate)
(unless rest?
(emit-br-if-npos-gt asm nreq (+ nreq nopt) alternate)))
(emit-assert-nargs-ge asm nreq))
(let ((ntotal (fold (lambda (kw ntotal)
(match kw
(((? keyword?) . idx)
(max (1+ idx) ntotal))))
(+ nreq nopt) kw-indices)))
;; FIXME: port 581f410f
(emit-bind-kwargs asm nreq
(pack-flags allow-other-keys? rest?)
(+ nreq nopt)
ntotal
(intern-constant asm kw-indices))
(emit-alloc-frame asm nlocals)))
(define-macro-assembler (label asm sym)
(hashq-set! (asm-labels asm) sym (asm-start asm)))
(define-macro-assembler (source asm source)
(set-asm-sources! asm (acons (asm-start asm) source (asm-sources asm))))
(define-macro-assembler (cache-current-module! asm module scope)
(let ((mod-label (intern-module-cache-cell asm scope)))
(emit-static-set! asm module mod-label 0)))
(define-macro-assembler (cached-toplevel-box asm dst scope sym bound?)
(let ((sym-label (intern-non-immediate asm sym))
(mod-label (intern-module-cache-cell asm scope))
(cell-label (intern-cache-cell asm scope sym)))
(emit-toplevel-box asm dst cell-label mod-label sym-label bound?)))
(define-macro-assembler (cached-module-box asm dst module-name sym public? bound?)
(let* ((sym-label (intern-non-immediate asm sym))
(key (cons public? module-name))
(mod-name-label (intern-constant asm key))
(cell-label (intern-cache-cell asm key sym)))
(emit-module-box asm dst cell-label mod-name-label sym-label bound?)))
(define-macro-assembler (dead-slot-map asm proc-slot dead-slot-map)
(unless (zero? dead-slot-map)
(set-asm-dead-slot-maps! asm
(cons
(cons* (asm-start asm) proc-slot dead-slot-map)
(asm-dead-slot-maps asm)))))
;;;
;;; Helper for linking objects.
;;;
(define (make-object asm name bv relocs labels . kwargs)
"Make a linker object. This helper handles interning the name in the
shstrtab, assigning the size, allocating a fresh index, and defining a
corresponding linker symbol for the start of the section."
(let ((name-idx (intern-section-name! asm (symbol->string name)))
(index (asm-next-section-number asm)))
(set-asm-next-section-number! asm (1+ index))
(make-linker-object (apply make-elf-section
#:index index
#:name name-idx
#:size (bytevector-length bv)
kwargs)
bv relocs
(cons (make-linker-symbol name 0) labels))))
;;;
;;; Linking the constant table. This code is somewhat intertwingled
;;; with the intern-constant code above, as that procedure also
;;; residualizes instructions to initialize constants at load time.
;;;
(define (write-immediate asm buf pos x)
(let ((val (object-address x))
(endianness (asm-endianness asm)))
(case (asm-word-size asm)
((4) (bytevector-u32-set! buf pos val endianness))
((8) (bytevector-u64-set! buf pos val endianness))
(else (error "bad word size" asm)))))
(define (emit-init-constants asm)
"If there is writable data that needs initialization at runtime, emit
a procedure to do that and return its label. Otherwise return
@code{#f}."
(let ((inits (asm-inits asm)))
(and (not (null? inits))
(let ((label (gensym "init-constants")))
(emit-text asm
`((begin-program ,label ())
(assert-nargs-ee/locals 1 1)
,@(reverse inits)
(load-constant 1 ,*unspecified*)
(return 1)
(end-program)))
label))))
(define (link-data asm data name)
"Link the static data for a program into the @var{name} section (which
should be .data or .rodata), and return the resulting linker object.
@var{data} should be a vhash mapping objects to labels."
(define (align address alignment)
(+ address
(modulo (- alignment (modulo address alignment)) alignment)))
(define tc7-vector 13)
(define stringbuf-shared-flag #x100)
(define stringbuf-wide-flag #x400)
(define tc7-stringbuf 39)
(define tc7-narrow-stringbuf
(+ tc7-stringbuf stringbuf-shared-flag))
(define tc7-wide-stringbuf
(+ tc7-stringbuf stringbuf-shared-flag stringbuf-wide-flag))
(define tc7-ro-string (+ 21 #x200))
(define tc7-program 69)
(define tc7-bytevector 77)
(define tc7-bitvector 95)
(let ((word-size (asm-word-size asm))
(endianness (asm-endianness asm)))
(define (byte-length x)
(cond
((stringbuf? x)
(let ((x (stringbuf-string x)))
(+ (* 2 word-size)
(case (string-bytes-per-char x)
((1) (1+ (string-length x)))
((4) (* (1+ (string-length x)) 4))
(else (error "bad string bytes per char" x))))))
((static-procedure? x)
(* 2 word-size))
((string? x)
(* 4 word-size))
((pair? x)
(* 2 word-size))
((simple-vector? x)
(* (1+ (vector-length x)) word-size))
((simple-uniform-vector? x)
(* 4 word-size))
((uniform-vector-backing-store? x)
(bytevector-length (uniform-vector-backing-store-bytes x)))
(else
word-size)))
(define (write-constant-reference buf pos x)
;; The asm-inits will fix up any reference to a non-immediate.
(write-immediate asm buf pos (if (immediate? x) x #f)))
(define (write buf pos obj)
(cond
((stringbuf? obj)
(let* ((x (stringbuf-string obj))
(len (string-length x))
(tag (if (= (string-bytes-per-char x) 1)
tc7-narrow-stringbuf
tc7-wide-stringbuf)))
(case word-size
((4)
(bytevector-u32-set! buf pos tag endianness)
(bytevector-u32-set! buf (+ pos 4) len endianness))
((8)
(bytevector-u64-set! buf pos tag endianness)
(bytevector-u64-set! buf (+ pos 8) len endianness))
(else
(error "bad word size" asm)))
(let ((pos (+ pos (* word-size 2))))
(case (string-bytes-per-char x)
((1)
(let lp ((i 0))
(if (< i len)
(let ((u8 (char->integer (string-ref x i))))
(bytevector-u8-set! buf (+ pos i) u8)
(lp (1+ i)))
(bytevector-u8-set! buf (+ pos i) 0))))
((4)
(let lp ((i 0))
(if (< i len)
(let ((u32 (char->integer (string-ref x i))))
(bytevector-u32-set! buf (+ pos (* i 4)) u32 endianness)
(lp (1+ i)))
(bytevector-u32-set! buf (+ pos (* i 4)) 0 endianness))))
(else (error "bad string bytes per char" x))))))
((static-procedure? obj)
(case word-size
((4)
(bytevector-u32-set! buf pos tc7-program endianness)
(bytevector-u32-set! buf (+ pos 4) 0 endianness))
((8)
(bytevector-u64-set! buf pos tc7-program endianness)
(bytevector-u64-set! buf (+ pos 8) 0 endianness))
(else (error "bad word size"))))
((cache-cell? obj)
(write-immediate asm buf pos #f))
((string? obj)
(let ((tag (logior tc7-ro-string (ash (string-length obj) 8))))
(case word-size
((4)
(bytevector-u32-set! buf pos tc7-ro-string endianness)
(write-immediate asm buf (+ pos 4) #f) ; stringbuf
(bytevector-u32-set! buf (+ pos 8) 0 endianness)
(bytevector-u32-set! buf (+ pos 12) (string-length obj) endianness))
((8)
(bytevector-u64-set! buf pos tc7-ro-string endianness)
(write-immediate asm buf (+ pos 8) #f) ; stringbuf
(bytevector-u64-set! buf (+ pos 16) 0 endianness)
(bytevector-u64-set! buf (+ pos 24) (string-length obj) endianness))
(else (error "bad word size")))))
((pair? obj)
(write-constant-reference buf pos (car obj))
(write-constant-reference buf (+ pos word-size) (cdr obj)))
((simple-vector? obj)
(let* ((len (vector-length obj))
(tag (logior tc7-vector (ash len 8))))
(case word-size
((4) (bytevector-u32-set! buf pos tag endianness))
((8) (bytevector-u64-set! buf pos tag endianness))
(else (error "bad word size")))
(let lp ((i 0))
(when (< i (vector-length obj))
(let ((pos (+ pos word-size (* i word-size)))
(elt (vector-ref obj i)))
(write-constant-reference buf pos elt)
(lp (1+ i)))))))
((symbol? obj)
(write-immediate asm buf pos #f))
((keyword? obj)
(write-immediate asm buf pos #f))
((number? obj)
(write-immediate asm buf pos #f))
((simple-uniform-vector? obj)
(let ((tag (if (bitvector? obj)
tc7-bitvector
(let ((type-code (array-type-code obj)))
(logior tc7-bytevector (ash type-code 7))))))
(case word-size
((4)
(bytevector-u32-set! buf pos tag endianness)
(bytevector-u32-set! buf (+ pos 4)
(if (bitvector? obj)
(bitvector-length obj)
(bytevector-length obj))
endianness) ; length
(bytevector-u32-set! buf (+ pos 8) 0 endianness) ; pointer
(write-immediate asm buf (+ pos 12) #f)) ; owner
((8)
(bytevector-u64-set! buf pos tag endianness)
(bytevector-u64-set! buf (+ pos 8)
(if (bitvector? obj)
(bitvector-length obj)
(bytevector-length obj))
endianness) ; length
(bytevector-u64-set! buf (+ pos 16) 0 endianness) ; pointer
(write-immediate asm buf (+ pos 24) #f)) ; owner
(else (error "bad word size")))))
((uniform-vector-backing-store? obj)
(let ((bv (uniform-vector-backing-store-bytes obj)))
(bytevector-copy! bv 0 buf pos (bytevector-length bv))
(unless (or (= 1 (uniform-vector-backing-store-element-size obj))
(eq? endianness (native-endianness)))
;; Need to swap units of element-size bytes
(error "FIXME: Implement byte order swap"))))
(else
(error "unrecognized object" obj))))
(cond
((vlist-null? data) #f)
(else
(let* ((byte-len (vhash-fold (lambda (k v len)
(+ (byte-length k) (align len 8)))
0 data))
(buf (make-bytevector byte-len 0)))
(let lp ((i 0) (pos 0) (symbols '()))
(if (< i (vlist-length data))
(let* ((pair (vlist-ref data i))
(obj (car pair))
(obj-label (cdr pair)))
(write buf pos obj)
(lp (1+ i)
(align (+ (byte-length obj) pos) 8)
(cons (make-linker-symbol obj-label pos) symbols)))
(make-object asm name buf '() symbols
#:flags (match name
('.data (logior SHF_ALLOC SHF_WRITE))
('.rodata SHF_ALLOC))))))))))
(define (link-constants asm)
"Link sections to hold constants needed by the program text emitted
using @var{asm}.
Returns three values: an object for the .rodata section, an object for
the .data section, and a label for an initialization procedure. Any of
these may be @code{#f}."
(define (shareable? x)
(cond
((stringbuf? x) #t)
((pair? x)
(and (immediate? (car x)) (immediate? (cdr x))))
((simple-vector? x)
(let lp ((i 0))
(or (= i (vector-length x))
(and (immediate? (vector-ref x i))
(lp (1+ i))))))
((uniform-vector-backing-store? x) #t)
(else #f)))
(let* ((constants (asm-constants asm))
(len (vlist-length constants)))
(let lp ((i 0)
(ro vlist-null)
(rw vlist-null))
(if (= i len)
(values (link-data asm ro '.rodata)
(link-data asm rw '.data)
(emit-init-constants asm))
(let ((pair (vlist-ref constants i)))
(if (shareable? (car pair))
(lp (1+ i) (vhash-consq (car pair) (cdr pair) ro) rw)
(lp (1+ i) ro (vhash-consq (car pair) (cdr pair) rw))))))))
;;;
;;; Linking program text.
;;;
(define (process-relocs buf relocs labels)
"Patch up internal x8-s24 relocations, and any s32 relocations that
reference symbols in the text section. Return a list of linker
relocations for references to symbols defined outside the text section."
(fold
(lambda (reloc tail)
(match reloc
((type label base word)
(let ((abs (hashq-ref labels label))
(dst (+ base word)))
(case type
((s32)
(if abs
(let ((rel (- abs base)))
(s32-set! buf dst rel)
tail)
(cons (make-linker-reloc 'rel32/4 (* dst 4) word label)
tail)))
((x8-s24)
(unless abs
(error "unbound near relocation" reloc))
(let ((rel (- abs base))
(u32 (u32-ref buf dst)))
(u32-set! buf dst (pack-u8-s24 (logand u32 #xff) rel))
tail))
(else (error "bad relocation kind" reloc)))))))
'()
relocs))
(define (process-labels labels)
"Define linker symbols for the label-offset map in @var{labels}.
The offsets are expected to be expressed in words."
(hash-map->list (lambda (label loc)
(make-linker-symbol label (* loc 4)))
labels))
(define (swap-bytes! buf)
"Patch up the text buffer @var{buf}, swapping the endianness of each
32-bit unit."
(unless (zero? (modulo (bytevector-length buf) 4))
(error "unexpected length"))
(let ((byte-len (bytevector-length buf)))
(let lp ((pos 0))
(unless (= pos byte-len)
(bytevector-u32-set!
buf pos
(bytevector-u32-ref buf pos (endianness big))
(endianness little))
(lp (+ pos 4))))))
(define (link-text-object asm)
"Link the .rtl-text section, swapping the endianness of the bytes if
needed."
(let ((buf (make-u32vector (asm-pos asm))))
(let lp ((pos 0) (prev (reverse (asm-prev asm))))
(if (null? prev)
(let ((byte-size (* (asm-idx asm) 4)))
(bytevector-copy! (asm-cur asm) 0 buf pos byte-size)
(unless (eq? (asm-endianness asm) (native-endianness))
(swap-bytes! buf))
(make-object asm '.rtl-text
buf
(process-relocs buf (asm-relocs asm)
(asm-labels asm))
(process-labels (asm-labels asm))))
(let ((len (* *block-size* 4)))
(bytevector-copy! (car prev) 0 buf pos len)
(lp (+ pos len) (cdr prev)))))))
;;;
;;; Create the frame maps. These maps are used by GC to identify dead
;;; slots in pending call frames, to avoid marking them. We only do
;;; this when frame makes a non-tail call, as that is the common case.
;;; Only the topmost frame will see a GC at any other point, but we mark
;;; top frames conservatively as serializing live slot maps at every
;;; instruction would take up too much space in the object file.
;;;
;; The .guile.frame-maps section starts with two packed u32 values: one
;; indicating the offset of the first byte of the .rtl-text section, and
;; another indicating the relative offset in bytes of the slots data.
(define frame-maps-prefix-len 8)
;; Each header is 8 bytes: 4 for the offset from .rtl_text, and 4 for
;; the offset of the slot map from the beginning of the
;; .guile.frame-maps section. The length of a frame map depends on the
;; frame size at the call site, and is not encoded into this section as
;; it is available at run-time.
(define frame-map-header-len 8)
(define (link-frame-maps asm)
(define (map-byte-length proc-slot)
(ceiling-quotient (- proc-slot 2) 8))
(define (make-frame-maps maps count map-len)
(let* ((endianness (asm-endianness asm))
(header-pos frame-maps-prefix-len)
(map-pos (+ header-pos (* count frame-map-header-len)))
(bv (make-bytevector (+ map-pos map-len) 0)))
(bytevector-u32-set! bv 4 map-pos endianness)
(let lp ((maps maps) (header-pos header-pos) (map-pos map-pos))
(match maps
(()
(make-object asm '.guile.frame-maps bv
(list (make-linker-reloc 'abs32/1 0 0 '.rtl-text))
'() #:type SHT_PROGBITS #:flags SHF_ALLOC))
(((pos proc-slot . map) . maps)
(bytevector-u32-set! bv header-pos (* pos 4) endianness)
(bytevector-u32-set! bv (+ header-pos 4) map-pos endianness)
(let write-bytes ((map-pos map-pos)
(map map)
(byte-length (map-byte-length proc-slot)))
(if (zero? byte-length)
(lp maps (+ header-pos frame-map-header-len) map-pos)
(begin
(bytevector-u8-set! bv map-pos (logand map #xff))
(write-bytes (1+ map-pos) (ash map -8)
(1- byte-length))))))))))
(match (asm-dead-slot-maps asm)
(() #f)
(in
(let lp ((in in) (out '()) (count 0) (map-len 0))
(match in
(() (make-frame-maps out count map-len))
(((and head (pos proc-slot . map)) . in)
(lp in (cons head out)
(1+ count)
(+ (map-byte-length proc-slot) map-len))))))))
;;;
;;; Linking other sections of the ELF file, like the dynamic segment,
;;; the symbol table, etc.
;;;
;; FIXME: Define these somewhere central, shared with C.
(define *bytecode-major-version* #x0202)
(define *bytecode-minor-version* 4)
(define (link-dynamic-section asm text rw rw-init frame-maps)
"Link the dynamic section for an ELF image with bytecode @var{text},
given the writable data section @var{rw} needing fixup from the
procedure with label @var{rw-init}. @var{rw-init} may be false. If
@var{rw} is true, it will be added to the GC roots at runtime."
(define-syntax-rule (emit-dynamic-section word-size %set-uword! reloc-type)
(let* ((endianness (asm-endianness asm))
(words 6)
(words (if rw (+ words 4) words))
(words (if rw-init (+ words 2) words))
(words (if frame-maps (+ words 2) words))
(bv (make-bytevector (* word-size words) 0))
(set-uword!
(lambda (i uword)
(%set-uword! bv (* i word-size) uword endianness)))
(relocs '())
(set-label!
(lambda (i label)
(set! relocs (cons (make-linker-reloc 'reloc-type
(* i word-size) 0 label)
relocs))
(%set-uword! bv (* i word-size) 0 endianness))))
(set-uword! 0 DT_GUILE_VM_VERSION)
(set-uword! 1 (logior (ash *bytecode-major-version* 16)
*bytecode-minor-version*))
(set-uword! 2 DT_GUILE_ENTRY)
(set-label! 3 '.rtl-text)
(when rw
;; Add roots to GC.
(set-uword! 4 DT_GUILE_GC_ROOT)
(set-label! 5 '.data)
(set-uword! 6 DT_GUILE_GC_ROOT_SZ)
(set-uword! 7 (bytevector-length (linker-object-bv rw)))
(when rw-init
(set-uword! 8 DT_INIT) ; constants
(set-label! 9 rw-init)))
(when frame-maps
(set-uword! (- words 4) DT_GUILE_FRAME_MAPS)
(set-label! (- words 3) '.guile.frame-maps))
(set-uword! (- words 2) DT_NULL)
(set-uword! (- words 1) 0)
(make-object asm '.dynamic bv relocs '()
#:type SHT_DYNAMIC #:flags SHF_ALLOC)))
(case (asm-word-size asm)
((4) (emit-dynamic-section 4 bytevector-u32-set! abs32/1))
((8) (emit-dynamic-section 8 bytevector-u64-set! abs64/1))
(else (error "bad word size" asm))))
(define (link-shstrtab asm)
"Link the string table for the section headers."
(intern-section-name! asm ".shstrtab")
(make-object asm '.shstrtab
(link-string-table! (asm-shstrtab asm))
'() '()
#:type SHT_STRTAB #:flags 0))
(define (link-symtab text-section asm)
(let* ((endianness (asm-endianness asm))
(word-size (asm-word-size asm))
(size (elf-symbol-len word-size))
(meta (reverse (asm-meta asm)))
(n (length meta))
(strtab (make-string-table))
(bv (make-bytevector (* n size) 0)))
(define (intern-string! name)
(string-table-intern! strtab (if name (symbol->string name) "")))
(for-each
(lambda (meta n)
(let ((name (intern-string! (meta-name meta))))
(write-elf-symbol bv (* n size) endianness word-size
(make-elf-symbol
#:name name
;; Symbol value and size are measured in
;; bytes, not u32s.
#:value (* 4 (meta-low-pc meta))
#:size (* 4 (- (meta-high-pc meta)
(meta-low-pc meta)))
#:type STT_FUNC
#:visibility STV_HIDDEN
#:shndx (elf-section-index text-section)))))
meta (iota n))
(let ((strtab (make-object asm '.strtab
(link-string-table! strtab)
'() '()
#:type SHT_STRTAB #:flags 0)))
(values (make-object asm '.symtab
bv
'() '()
#:type SHT_SYMTAB #:flags 0 #:entsize size
#:link (elf-section-index
(linker-object-section strtab)))
strtab))))
;;; The .guile.arities section describes the arities that a function can
;;; have. It is in two parts: a sorted array of headers describing
;;; basic arities, and an array of links out to a string table (and in
;;; the case of keyword arguments, to the data section) for argument
;;; names. The whole thing is prefixed by a uint32 indicating the
;;; offset of the end of the headers array.
;;;
;;; The arity headers array is a packed array of structures of the form:
;;;
;;; struct arity_header {
;;; uint32_t low_pc;
;;; uint32_t high_pc;
;;; uint32_t offset;
;;; uint32_t flags;
;;; uint32_t nreq;
;;; uint32_t nopt;
;;; }
;;;
;;; All of the offsets and addresses are 32 bits. We can expand in the
;;; future to use 64-bit offsets if appropriate, but there are other
;;; aspects of bytecode that constrain us to a total image that fits in
;;; 32 bits, so for the moment we'll simplify the problem space.
;;;
;;; The following flags values are defined:
;;;
;;; #x1: has-rest?
;;; #x2: allow-other-keys?
;;; #x4: has-keyword-args?
;;; #x8: is-case-lambda?
;;; #x10: is-in-case-lambda?
;;;
;;; Functions with a single arity specify their number of required and
;;; optional arguments in nreq and nopt, and do not have the
;;; is-case-lambda? flag set. Their "offset" member links to an array
;;; of pointers into the associated .guile.arities.strtab string table,
;;; identifying the argument names. This offset is relative to the
;;; start of the .guile.arities section. Links for required arguments
;;; are first, in order, as uint32 values. Next follow the optionals,
;;; then the rest link if has-rest? is set, then a link to the "keyword
;;; indices" literal if has-keyword-args? is set. Unlike the other
;;; links, the kw-indices link points into the data section, and is
;;; relative to the ELF image as a whole.
;;;
;;; Functions with no arities have no arities information present in the
;;; .guile.arities section.
;;;
;;; Functions with multiple arities are preceded by a header with
;;; is-case-lambda? set. All other fields are 0, except low-pc and
;;; high-pc which should be the bounds of the whole function. Headers
;;; for the individual arities follow, with the is-in-case-lambda? flag
;;; set. In this way the whole headers array is sorted in increasing
;;; low-pc order, and case-lambda clauses are contained within the
;;; [low-pc, high-pc] of the case-lambda header.
;; Length of the prefix to the arities section, in bytes.
(define arities-prefix-len 4)
;; Length of an arity header, in bytes.
(define arity-header-len (* 6 4))
;; The offset of "offset" within arity header, in bytes.
(define arity-header-offset-offset (* 2 4))
(define-syntax-rule (pack-arity-flags has-rest? allow-other-keys?
has-keyword-args? is-case-lambda?
is-in-case-lambda?)
(logior (if has-rest? (ash 1 0) 0)
(if allow-other-keys? (ash 1 1) 0)
(if has-keyword-args? (ash 1 2) 0)
(if is-case-lambda? (ash 1 3) 0)
(if is-in-case-lambda? (ash 1 4) 0)))
(define (meta-arities-size meta)
(define (lambda-size arity)
(+ arity-header-len
(* 4 ;; name pointers
(+ (length (arity-req arity))
(length (arity-opt arity))
(if (arity-rest arity) 1 0)
(if (pair? (arity-kw-indices arity)) 1 0)))))
(define (case-lambda-size arities)
(fold +
arity-header-len ;; case-lambda header
(map lambda-size arities))) ;; the cases
(match (meta-arities meta)
(() 0)
((arity) (lambda-size arity))
(arities (case-lambda-size arities))))
(define (write-arity-headers metas bv endianness)
(define (write-arity-header* pos low-pc high-pc flags nreq nopt)
(bytevector-u32-set! bv pos (* low-pc 4) endianness)
(bytevector-u32-set! bv (+ pos 4) (* high-pc 4) endianness)
(bytevector-u32-set! bv (+ pos 8) 0 endianness) ; offset
(bytevector-u32-set! bv (+ pos 12) flags endianness)
(bytevector-u32-set! bv (+ pos 16) nreq endianness)
(bytevector-u32-set! bv (+ pos 20) nopt endianness))
(define (write-arity-header pos arity in-case-lambda?)
(write-arity-header* pos (arity-low-pc arity)
(arity-high-pc arity)
(pack-arity-flags (arity-rest arity)
(arity-allow-other-keys? arity)
(pair? (arity-kw-indices arity))
#f
in-case-lambda?)
(length (arity-req arity))
(length (arity-opt arity))))
(let lp ((metas metas) (pos arities-prefix-len) (offsets '()))
(match metas
(()
;; Fill in the prefix.
(bytevector-u32-set! bv 0 pos endianness)
(values pos (reverse offsets)))
((meta . metas)
(match (meta-arities meta)
(() (lp metas pos offsets))
((arity)
(write-arity-header pos arity #f)
(lp metas
(+ pos arity-header-len)
(acons arity (+ pos arity-header-offset-offset) offsets)))
(arities
;; Write a case-lambda header, then individual arities.
;; The case-lambda header's offset link is 0.
(write-arity-header* pos (meta-low-pc meta) (meta-high-pc meta)
(pack-arity-flags #f #f #f #t #f) 0 0)
(let lp* ((arities arities) (pos (+ pos arity-header-len))
(offsets offsets))
(match arities
(() (lp metas pos offsets))
((arity . arities)
(write-arity-header pos arity #t)
(lp* arities
(+ pos arity-header-len)
(acons arity
(+ pos arity-header-offset-offset)
offsets)))))))))))
(define (write-arity-links asm bv pos arity-offset-pairs strtab)
(define (write-symbol sym pos)
(bytevector-u32-set! bv pos
(string-table-intern! strtab (symbol->string sym))
(asm-endianness asm))
(+ pos 4))
(define (write-kw-indices pos kw-indices)
;; FIXME: Assert that kw-indices is already interned.
(make-linker-reloc 'abs32/1 pos 0
(intern-constant asm kw-indices)))
(let lp ((pos pos) (pairs arity-offset-pairs) (relocs '()))
(match pairs
(()
(unless (= pos (bytevector-length bv))
(error "expected to fully fill the bytevector"
pos (bytevector-length bv)))
relocs)
(((arity . offset) . pairs)
(bytevector-u32-set! bv offset pos (asm-endianness asm))
(let ((pos (fold write-symbol
pos
(append (arity-req arity)
(arity-opt arity)
(cond
((arity-rest arity) => list)
(else '()))))))
(match (arity-kw-indices arity)
(() (lp pos pairs relocs))
(kw-indices
(lp (+ pos 4)
pairs
(cons (write-kw-indices pos kw-indices) relocs)))))))))
(define (link-arities asm)
(let* ((endianness (asm-endianness asm))
(metas (reverse (asm-meta asm)))
(size (fold (lambda (meta size)
(+ size (meta-arities-size meta)))
arities-prefix-len
metas))
(strtab (make-string-table))
(bv (make-bytevector size 0)))
(let ((kw-indices-relocs
(call-with-values
(lambda ()
(write-arity-headers metas bv endianness))
(lambda (pos arity-offset-pairs)
(write-arity-links asm bv pos arity-offset-pairs strtab)))))
(let ((strtab (make-object asm '.guile.arities.strtab
(link-string-table! strtab)
'() '()
#:type SHT_STRTAB #:flags 0)))
(values (make-object asm '.guile.arities
bv
kw-indices-relocs '()
#:type SHT_PROGBITS #:flags 0
#:link (elf-section-index
(linker-object-section strtab)))
strtab)))))
;;;
;;; The .guile.docstrs section is a packed, sorted array of (pc, str)
;;; values. Pc and str are both 32 bits wide. (Either could change to
;;; 64 bits if appropriate in the future.) Pc is the address of the
;;; entry to a program, relative to the start of the text section, in
;;; bytes, and str is an index into the associated .guile.docstrs.strtab
;;; string table section.
;;;
;; The size of a docstrs entry, in bytes.
(define docstr-size 8)
(define (link-docstrs asm)
(define (find-docstrings)
(filter-map (lambda (meta)
(define (is-documentation? pair)
(eq? (car pair) 'documentation))
(let* ((props (meta-properties meta))
(tail (find-tail is-documentation? props)))
(and tail
(not (find-tail is-documentation? (cdr tail)))
(string? (cdar tail))
(cons (* 4 (meta-low-pc meta)) (cdar tail)))))
(reverse (asm-meta asm))))
(let* ((endianness (asm-endianness asm))
(docstrings (find-docstrings))
(strtab (make-string-table))
(bv (make-bytevector (* (length docstrings) docstr-size) 0)))
(fold (lambda (pair pos)
(match pair
((pc . string)
(bytevector-u32-set! bv pos pc endianness)
(bytevector-u32-set! bv (+ pos 4)
(string-table-intern! strtab string)
endianness)
(+ pos docstr-size))))
0
docstrings)
(let ((strtab (make-object asm '.guile.docstrs.strtab
(link-string-table! strtab)
'() '()
#:type SHT_STRTAB #:flags 0)))
(values (make-object asm '.guile.docstrs
bv
'() '()
#:type SHT_PROGBITS #:flags 0
#:link (elf-section-index
(linker-object-section strtab)))
strtab))))
;;;
;;; The .guile.procprops section is a packed, sorted array of (pc, addr)
;;; values. Pc and addr are both 32 bits wide. (Either could change to
;;; 64 bits if appropriate in the future.) Pc is the address of the
;;; entry to a program, relative to the start of the text section, and
;;; addr is the address of the associated properties alist, relative to
;;; the start of the ELF image.
;;;
;;; Since procedure properties are stored in the data sections, we need
;;; to link the procedures property section first. (Note that this
;;; constraint does not apply to the arities section, which may
;;; reference the data sections via the kw-indices literal, because
;;; assembling the text section already makes sure that the kw-indices
;;; are interned.)
;;;
;; The size of a procprops entry, in bytes.
(define procprops-size 8)
(define (link-procprops asm)
(define (assoc-remove-one alist key value-pred)
(match alist
(() '())
((((? (lambda (x) (eq? x key))) . value) . alist)
(if (value-pred value)
alist
(acons key value alist)))
(((k . v) . alist)
(acons k v (assoc-remove-one alist key value-pred)))))
(define (props-without-name-or-docstring meta)
(assoc-remove-one
(assoc-remove-one (meta-properties meta) 'name (lambda (x) #t))
'documentation
string?))
(define (find-procprops)
(filter-map (lambda (meta)
(let ((props (props-without-name-or-docstring meta)))
(and (pair? props)
(cons (* 4 (meta-low-pc meta)) props))))
(reverse (asm-meta asm))))
(let* ((endianness (asm-endianness asm))
(procprops (find-procprops))
(bv (make-bytevector (* (length procprops) procprops-size) 0)))
(let lp ((procprops procprops) (pos 0) (relocs '()))
(match procprops
(()
(make-object asm '.guile.procprops
bv
relocs '()
#:type SHT_PROGBITS #:flags 0))
(((pc . props) . procprops)
(bytevector-u32-set! bv pos pc endianness)
(lp procprops
(+ pos procprops-size)
(cons (make-linker-reloc 'abs32/1 (+ pos 4) 0
(intern-constant asm props))
relocs)))))))
;;;
;;; The DWARF .debug_info, .debug_abbrev, .debug_str, and .debug_loc
;;; sections provide line number and local variable liveness
;;; information. Their format is defined by the DWARF
;;; specifications.
;;;
(define (asm-language asm)
;; FIXME: Plumb language through to the assembler.
'scheme)
;; -> 5 values: .debug_info, .debug_abbrev, .debug_str, .debug_loc, .debug_lines
(define (link-debug asm)
(define (put-s8 port val)
(let ((bv (make-bytevector 1)))
(bytevector-s8-set! bv 0 val)
(put-bytevector port bv)))
(define (put-u16 port val)
(let ((bv (make-bytevector 2)))
(bytevector-u16-set! bv 0 val (asm-endianness asm))
(put-bytevector port bv)))
(define (put-u32 port val)
(let ((bv (make-bytevector 4)))
(bytevector-u32-set! bv 0 val (asm-endianness asm))
(put-bytevector port bv)))
(define (put-u64 port val)
(let ((bv (make-bytevector 8)))
(bytevector-u64-set! bv 0 val (asm-endianness asm))
(put-bytevector port bv)))
(define (put-uleb128 port val)
(let lp ((val val))
(let ((next (ash val -7)))
(if (zero? next)
(put-u8 port val)
(begin
(put-u8 port (logior #x80 (logand val #x7f)))
(lp next))))))
(define (put-sleb128 port val)
(let lp ((val val))
(if (<= 0 (+ val 64) 127)
(put-u8 port (logand val #x7f))
(begin
(put-u8 port (logior #x80 (logand val #x7f)))
(lp (ash val -7))))))
(define (port-position port)
(seek port 0 SEEK_CUR))
(define (meta->subprogram-die meta)
`(subprogram
(@ ,@(cond
((meta-name meta)
=> (lambda (name) `((name ,(symbol->string name)))))
(else
'()))
(low-pc ,(meta-label meta))
(high-pc ,(* 4 (- (meta-high-pc meta) (meta-low-pc meta)))))))
(define (make-compile-unit-die asm)
`(compile-unit
(@ (producer ,(string-append "Guile " (version)))
(language ,(asm-language asm))
(low-pc .rtl-text)
(high-pc ,(* 4 (asm-pos asm)))
(stmt-list 0))
,@(map meta->subprogram-die (reverse (asm-meta asm)))))
(let-values (((die-port get-die-bv) (open-bytevector-output-port))
((die-relocs) '())
((abbrev-port get-abbrev-bv) (open-bytevector-output-port))
;; (tag has-kids? attrs forms) -> code
((abbrevs) vlist-null)
((strtab) (make-string-table))
((line-port get-line-bv) (open-bytevector-output-port))
((line-relocs) '())
;; file -> code
((files) vlist-null))
(define (write-abbrev code tag has-children? attrs forms)
(put-uleb128 abbrev-port code)
(put-uleb128 abbrev-port (tag-name->code tag))
(put-u8 abbrev-port (children-name->code (if has-children? 'yes 'no)))
(for-each (lambda (attr form)
(put-uleb128 abbrev-port (attribute-name->code attr))
(put-uleb128 abbrev-port (form-name->code form)))
attrs forms)
(put-uleb128 abbrev-port 0)
(put-uleb128 abbrev-port 0))
(define (intern-abbrev tag has-children? attrs forms)
(let ((key (list tag has-children? attrs forms)))
(match (vhash-assoc key abbrevs)
((_ . code) code)
(#f (let ((code (1+ (vlist-length abbrevs))))
(set! abbrevs (vhash-cons key code abbrevs))
(write-abbrev code tag has-children? attrs forms)
code)))))
(define (intern-file file)
(match (vhash-assoc file files)
((_ . code) code)
(#f (let ((code (1+ (vlist-length files))))
(set! files (vhash-cons file code files))
code))))
(define (write-sources)
;; Choose line base and line range values that will allow for an
;; address advance range of 16 words. The special opcode range is
;; from 10 to 255, so 246 values.
(define base -4)
(define range 15)
(let lp ((sources (asm-sources asm)) (out '()))
(match sources
(((pc . s) . sources)
(let ((file (assq-ref s 'filename))
(line (assq-ref s 'line))
(col (assq-ref s 'column)))
(lp sources
;; Guile line and column numbers are 0-indexed, but
;; they are 1-indexed for DWARF.
(cons (list pc
(if file (intern-file file) 0)
(if line (1+ line))
(if col (1+ col)))
out))))
(()
;; Compilation unit header for .debug_line. We write in
;; DWARF 2 format because more tools understand it than DWARF
;; 4, which incompatibly adds another field to this header.
(put-u32 line-port 0) ; Length; will patch later.
(put-u16 line-port 2) ; DWARF 2 format.
(put-u32 line-port 0) ; Prologue length; will patch later.
(put-u8 line-port 4) ; Minimum instruction length: 4 bytes.
(put-u8 line-port 1) ; Default is-stmt: true.
(put-s8 line-port base) ; Line base. See the DWARF standard.
(put-u8 line-port range) ; Line range. See the DWARF standard.
(put-u8 line-port 10) ; Opcode base: the first "special" opcode.
;; A table of the number of uleb128 arguments taken by each
;; of the standard opcodes.
(put-u8 line-port 0) ; 1: copy
(put-u8 line-port 1) ; 2: advance-pc
(put-u8 line-port 1) ; 3: advance-line
(put-u8 line-port 1) ; 4: set-file
(put-u8 line-port 1) ; 5: set-column
(put-u8 line-port 0) ; 6: negate-stmt
(put-u8 line-port 0) ; 7: set-basic-block
(put-u8 line-port 0) ; 8: const-add-pc
(put-u8 line-port 1) ; 9: fixed-advance-pc
;; Include directories, as a zero-terminated sequence of
;; nul-terminated strings. Nothing, for the moment.
(put-u8 line-port 0)
;; File table. For each file that contributes to this
;; compilation unit, a nul-terminated file name string, and a
;; uleb128 for each of directory the file was found in, the
;; modification time, and the file's size in bytes. We pass
;; zero for the latter three fields.
(vlist-fold-right
(lambda (pair seed)
(match pair
((file . code)
(put-bytevector line-port (string->utf8 file))
(put-u8 line-port 0)
(put-uleb128 line-port 0) ; directory
(put-uleb128 line-port 0) ; mtime
(put-uleb128 line-port 0))) ; size
seed)
#f
files)
(put-u8 line-port 0) ; 0 byte terminating file list.
;; Patch prologue length.
(let ((offset (port-position line-port)))
(seek line-port 6 SEEK_SET)
(put-u32 line-port (- offset 10))
(seek line-port offset SEEK_SET))
;; Now write the statement program.
(let ()
(define (extended-op opcode payload-len)
(put-u8 line-port 0) ; extended op
(put-uleb128 line-port (1+ payload-len)) ; payload-len + opcode
(put-uleb128 line-port opcode))
(define (set-address sym)
(define (add-reloc! kind)
(set! line-relocs
(cons (make-linker-reloc kind
(port-position line-port)
0
sym)
line-relocs)))
(match (asm-word-size asm)
(4
(extended-op 2 4)
(add-reloc! 'abs32/1)
(put-u32 line-port 0))
(8
(extended-op 2 8)
(add-reloc! 'abs64/1)
(put-u64 line-port 0))))
(define (end-sequence pc)
(let ((pc-inc (- (asm-pos asm) pc)))
(put-u8 line-port 2) ; advance-pc
(put-uleb128 line-port pc-inc))
(extended-op 1 0))
(define (advance-pc pc-inc line-inc)
(let ((spec (+ (- line-inc base) (* pc-inc range) 10)))
(cond
((or (< line-inc base) (>= line-inc (+ base range)))
(advance-line line-inc)
(advance-pc pc-inc 0))
((<= spec 255)
(put-u8 line-port spec))
((< spec 500)
(put-u8 line-port 8) ; const-advance-pc
(advance-pc (- pc-inc (floor/ (- 255 10) range))
line-inc))
(else
(put-u8 line-port 2) ; advance-pc
(put-uleb128 line-port pc-inc)
(advance-pc 0 line-inc)))))
(define (advance-line inc)
(put-u8 line-port 3)
(put-sleb128 line-port inc))
(define (set-file file)
(put-u8 line-port 4)
(put-uleb128 line-port file))
(define (set-column col)
(put-u8 line-port 5)
(put-uleb128 line-port col))
(set-address '.rtl-text)
(let lp ((in out) (pc 0) (file 1) (line 1) (col 0))
(match in
(()
(when (null? out)
;; There was no source info in the first place. Set
;; file register to 0 before adding final row.
(set-file 0))
(end-sequence pc))
(((pc* file* line* col*) . in*)
(cond
((and (eqv? file file*) (eqv? line line*) (eqv? col col*))
(lp in* pc file line col))
(else
(unless (eqv? col col*)
(set-column col*))
(unless (eqv? file file*)
(set-file file*))
(advance-pc (- pc* pc) (- line* line))
(lp in* pc* file* line* col*)))))))))))
(define (compute-code attr val)
(match attr
('name (string-table-intern! strtab val))
('low-pc val)
('high-pc val)
('producer (string-table-intern! strtab val))
('language (language-name->code val))
('stmt-list val)))
(define (exact-integer? val)
(and (number? val) (integer? val) (exact? val)))
(define (choose-form attr val code)
(cond
((string? val) 'strp)
((eq? attr 'stmt-list) 'sec-offset)
((exact-integer? code)
(cond
((< code 0) 'sleb128)
((<= code #xff) 'data1)
((<= code #xffff) 'data2)
((<= code #xffffffff) 'data4)
((<= code #xffffffffffffffff) 'data8)
(else 'uleb128)))
((symbol? val) 'addr)
(else (error "unhandled case" attr val code))))
(define (add-die-relocation! kind sym)
(set! die-relocs
(cons (make-linker-reloc kind (port-position die-port) 0 sym)
die-relocs)))
(define (write-value code form)
(match form
('data1 (put-u8 die-port code))
('data2 (put-u16 die-port code))
('data4 (put-u32 die-port code))
('data8 (put-u64 die-port code))
('uleb128 (put-uleb128 die-port code))
('sleb128 (put-sleb128 die-port code))
('addr
(match (asm-word-size asm)
(4
(add-die-relocation! 'abs32/1 code)
(put-u32 die-port 0))
(8
(add-die-relocation! 'abs64/1 code)
(put-u64 die-port 0))))
('sec-offset (put-u32 die-port code))
('strp (put-u32 die-port code))))
(define (write-die die)
(match die
((tag ('@ (attrs vals) ...) children ...)
(let* ((codes (map compute-code attrs vals))
(forms (map choose-form attrs vals codes))
(has-children? (not (null? children)))
(abbrev-code (intern-abbrev tag has-children? attrs forms)))
(put-uleb128 die-port abbrev-code)
(for-each write-value codes forms)
(when has-children?
(for-each write-die children)
(put-uleb128 die-port 0))))))
;; Compilation unit header.
(put-u32 die-port 0) ; Length; will patch later.
(put-u16 die-port 4) ; DWARF 4.
(put-u32 die-port 0) ; Abbrevs offset.
(put-u8 die-port (asm-word-size asm)) ; Address size.
(write-die (make-compile-unit-die asm))
;; Terminate the abbrevs list.
(put-uleb128 abbrev-port 0)
(write-sources)
(values (let ((bv (get-die-bv)))
;; Patch DWARF32 length.
(bytevector-u32-set! bv 0 (- (bytevector-length bv) 4)
(asm-endianness asm))
(make-object asm '.debug_info bv die-relocs '()
#:type SHT_PROGBITS #:flags 0))
(make-object asm '.debug_abbrev (get-abbrev-bv) '() '()
#:type SHT_PROGBITS #:flags 0)
(make-object asm '.debug_str (link-string-table! strtab) '() '()
#:type SHT_PROGBITS #:flags 0)
(make-object asm '.debug_loc #vu8() '() '()
#:type SHT_PROGBITS #:flags 0)
(let ((bv (get-line-bv)))
;; Patch DWARF32 length.
(bytevector-u32-set! bv 0 (- (bytevector-length bv) 4)
(asm-endianness asm))
(make-object asm '.debug_line bv line-relocs '()
#:type SHT_PROGBITS #:flags 0)))))
(define (link-objects asm)
(let*-values (;; Link procprops before constants, because it probably
;; interns more constants.
((procprops) (link-procprops asm))
((ro rw rw-init) (link-constants asm))
;; Link text object after constants, so that the
;; constants initializer gets included.
((text) (link-text-object asm))
((frame-maps) (link-frame-maps asm))
((dt) (link-dynamic-section asm text rw rw-init frame-maps))
((symtab strtab) (link-symtab (linker-object-section text) asm))
((arities arities-strtab) (link-arities asm))
((docstrs docstrs-strtab) (link-docstrs asm))
((dinfo dabbrev dstrtab dloc dline) (link-debug asm))
;; This needs to be linked last, because linking other
;; sections adds entries to the string table.
((shstrtab) (link-shstrtab asm)))
(filter identity
(list text ro frame-maps rw dt symtab strtab
arities arities-strtab
docstrs docstrs-strtab procprops
dinfo dabbrev dstrtab dloc dline
shstrtab))))
;;;
;;; High-level public interfaces.
;;;
(define* (link-assembly asm #:key (page-aligned? #t))
"Produce an ELF image from the code and data emitted into @var{asm}.
The result is a bytevector, by default linked so that read-only and
writable data are on separate pages. Pass @code{#:page-aligned? #f} to
disable this behavior."
(link-elf (link-objects asm) #:page-aligned? page-aligned?))