3268 - starting to support separate compilation - mu - Soul of a tiny new machine. More thorough tests → More comprehensible and rewrite-friendly software → More resilient society.

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author	Kartik K. Agaram <vc@akkartik.com>	2016-08-28 14:30:22 -0700
committer	Kartik K. Agaram <vc@akkartik.com>	2016-08-28 14:30:22 -0700
commit	0608409526d1a33265fa6ed20797eef45a79f78e (patch)
tree	4540347ff9d157b904c2867aaa3d0ecaf37b38ab /arc/fork.mu
parent	48153630c58b311d15771eefa046f6c68944a4a0 (diff)
download	mu-0608409526d1a33265fa6ed20797eef45a79f78e.tar.gz

3268 - starting to support separate compilation

Right now Mu has zero dependency knowledge. If anything changes in our
project the C++ compiler has to redo the entire project. This is
unnecessarily slow, and also causes gcc to run out of RAM on puny
machines.

New vision: carve the tangled mu.cc into multiple files.

  includes.h
  types.h
  globals.cc
  globals.h
  one .cc file for each function definition

(This is of course in addition to the already auto-generated test_list
and function_list.)

With this approach changes to functions will only require recompiling
the functions that changed. We'd need to be smart to not rewrite files
that don't change (modulo #line directives).

Any changes to includes/types/globals would still require rebuilding the
entire project. That's the (now greatly reduced) price we will continue
to pay for outsourcing dependency management to the computer.

Plan arrived at after conversation with Stephen Malina.

Diffstat (limited to 'arc/fork.mu')

0 files changed, 0 insertions, 0 deletions

# Helper to check an array's bounds, and to abort if they're violated. # Really only intended to be called from code generated by mu.subx. == code __check-mu-array-bounds: # index: int, elem-size: int, arr-size: int, function-name: (addr array byte), array-name: (addr array byte) # . prologue 55/push-ebp 89/<- %ebp 4/r32/esp # . save registers 50/push-eax 51/push-ecx 52/push-edx # . not bothering saving ebx; it's only clobbered if we're going to abort # ecx = arr-size 8b/-> *(ebp+0x10) 1/r32/ecx # var overflow/edx: int = 0 ba/copy-to-edx 0/imm32 # var offset/eax: int = index * elem-size 8b/-> *(ebp+8) 0/r32/eax f7 4/subop/multiply-eax-with *(ebp+0xc) # check for overflow 81 7/subop/compare %edx 0/imm32 0f 85/jump-if-!= __check-mu-array-bounds:overflow/disp32 # check bounds 39/compare %eax 1/r32/ecx 0f 82/jump-if-unsigned< $__check-mu-array-bounds:end/disp32 # negative index should always abort # abort if necessary (write-buffered Stderr "fn ") (write-buffered Stderr *(ebp+0x14)) (write-buffered Stderr ": offset ") (write-int32-hex-buffered Stderr %eax) (write-buffered Stderr " is too large for array '") (write-buffered Stderr *(ebp+0x18)) (write-buffered Stderr "'\n") (flush Stderr) # exit(1) bb/copy-to-ebx 1/imm32 e8/call syscall_exit/disp32 # never gets here $__check-mu-array-bounds:end: # . restore registers 5a/pop-to-edx 59/pop-to-ecx 58/pop-to-eax # . epilogue 89/<- %esp 5/r32/ebp 5d/pop-to-ebp c3/return __check-mu-array-bounds:overflow: # "fn " function-name ": offset to array '" array-name "' overflowed 32 bits\n" (write-buffered Stderr "fn ") (write-buffered Stderr *(ebp+0x14)) (write-buffered Stderr ": offset to array '") (write-buffered Stderr *(ebp+0x18)) (write-buffered Stderr "' overflowed 32 bits\n") (flush Stderr) # exit(1) bb/copy-to-ebx 1/imm32 e8/call syscall_exit/disp32 # never gets here # potential alternative #? __bounds-check: # msg: (addr array byte) #? (write-buffered Stderr "abort: array bounds exceeded in fn ") #? 8b/-> *(esp+4) 0/r32/eax # we're going to abort, so just clobber away #? (write-buffered Stderr %eax) #? (write-buffered Stderr Newline) #? # exit(1) #? bb/copy-to-ebx 1/imm32 #? e8/call syscall_exit/disp32 # to be called as follows: # var/reg <- index arr/rega: (addr array T), idx/regi: int # | if size-of(T) is 1, 2, 4 or 8 # => # temporarily save array size to reg to check bounds # "8b/-> *" rega " " reg "/r32" # "c1/shift 5/subop/right %" reg " " log2(size-of(T)) "/imm32" # "3b/compare " reg "/r32 *" rega # "68/push \"" function "\"/imm32" # pass function name to error message # "0f 8d/jump-if->= __bounds_check/disp32" # "81 0/subop/add %esp 4/imm32" # drop function name # # actually save the index addr in reg # "8d/copy-address *(" rega "+" regi "<<" log2(size-of(T)) "+4) " reg "/r32"


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