src/compiler/policies.lisp

   1 ;;;; aimed optimization qualities
   2
   3 ;;;; This software is part of the SBCL system. See the README file for
   4 ;;;; more information.
   5 ;;;;
   6 ;;;; This software is derived from the CMU CL system, which was
   7 ;;;; written at Carnegie Mellon University and released into the
   8 ;;;; public domain. The software is in the public domain and is
   9 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
  10 ;;;; files for more information.
  11
  12 (in-package "SB!C")
  13
  14 (define-optimization-quality check-constant-modification
  15     safety
  16   ("no" "maybe" "yes" "yes")
  17   "Control whether the compiler should check for constant
  18 modification. Defaults to SAFETY.")
  19
  20 (define-optimization-quality type-check
  21     ;; FIXME: grepping the tree for "policy.*safety" yields some
  22     ;; places which might want to use this instead -- or
  23     ;; some other derived policy.
  24     (cond ((= safety 0) 0)
  25           ((and (< safety 2) (< safety speed)) 2)
  26           (t 3))
  27   ("no" "maybe" "weak" "full")
  28   "Control the way to perform runtime type checking:
  29 0: declared types are simply trusted; no runtime checks are performed;
  30 2: fast checks are performed: declared types are weakened to
  31    FIXNUM/SINGLE-FLOAT/FLOAT/NUMBER/structure/specialized array etc.;
  32 3: declared types are fully checked (several exceptions exist;
  33    see \"SBCL User Manual\", Compiler->Handling of Types->
  34    Implementation Limitations for details).")
  35
  36 (define-optimization-quality check-tag-existence
  37     (cond ((= safety 0) 0)
  38           (t 3))
  39   ("no" "maybe" "yes" "yes")
  40   "Control whether GO and RETURN-FROM check liveness of the destination tag.
  41 Enabling this option can increase heap consing of closures.")
  42
  43 (define-optimization-quality let-conversion
  44     (if (<= debug speed) 3 0)
  45   ("off" "maybe" "on" "on")
  46   "Control inline-substitution of used-once local functions.")
  47
  48 (define-optimization-quality verify-arg-count
  49     (if (zerop safety) 0 3)
  50   ("no" "maybe" "yes" "yes"))
  51
  52 (define-optimization-quality merge-tail-calls
  53     (if (or (> space debug)
  54             (> speed debug))
  55         3
  56         0)
  57   ("no" "maybe" "yes" "yes")
  58   "Control whether tail-calls should reuse caller stack frame.
  59 Enabling this option make functions use less stack space, and make
  60 tail-recursive functions execute in constant stack, but debugging
  61 become harder, because backtraces show only part of function call
  62 sequence.
  63
  64 This options has no effect when INSERT-DEBUG-CATCH is set.")
  65
  66 (define-optimization-quality insert-debug-catch
  67     (if (> debug (max speed space))
  68         3
  69         0)
  70   ("no" "maybe" "yes" "yes")
  71   "Enable possibility of returning from stack frames with the debugger.
  72
  73 Enabling this option effectively disables MERGE-TAIL-CALLS.")
  74
  75 (define-optimization-quality recognize-self-calls
  76     (if (> (max speed space) debug)
  77         3
  78         0)
  79   ("no" "maybe" "yes" "yes")
  80   "When enabled, reference to a function FOO inside the body of (DEFUN
  81 FOO ...) is considered to be the reference to the function being
  82 defined. Calls to FOO are compiled as local. This allows better
  83 optimization and type checking, but TRACE will not show recursive
  84 calls. If the function object is bound to another name BAR, and FOO is
  85 bound to another function, calls to FOO inside BAR will remain to be
  86 recursive.
  87
  88 When disabled, internal references to a function FOO will be
  89 considered ti be a call of a function, bound to the symbol at
  90 run-time, which is less efficient. TRACE will show recursive calls. In
  91 case of renaming described above, calls to FOO will not be recursive
  92 and will refer to the new function, bound to FOO.")
  93
  94 (define-optimization-quality stack-allocate-dynamic-extent
  95     (if (and (> (max speed space) (max debug safety))
  96              (< safety 3))
  97         3
  98         0)
  99   ("no" "maybe" "yes" "yes")
 100   "Control whether allocate objects, declared DYNAMIC-EXTENT, on
 101 stack.")
 102
 103 (define-optimization-quality stack-allocate-vector
 104     (cond ((= stack-allocate-dynamic-extent 0) 0)
 105           ((= safety 0) 3)
 106           (t 2))
 107   ("no" "maybe" "one page" "yes")
 108   "Control what vectors, declared DYNAMIC-EXTENT, are allocated on stack:
 109 0: no vectors are allocated on stack;
 110 2: only short vectors (compiler knows them to fit on one page);
 111 3: every.
 112
 113 This option has an effect only when STACK-ALLOCATE-DYNAMIC-EXTENT is
 114 set.")
 115
 116 (define-optimization-quality float-accuracy
 117     3
 118   ("degraded" "full" "full" "full"))
 119
 120 (define-optimization-quality insert-step-conditions
 121     (if (> debug (max speed space compilation-speed))
 122         debug
 123         0)
 124   ("no" "no" "partial" "full")
 125   "Control instrumentation of code, enabling single-stepping through
 126 it in the debugger.
 127
 128 This option has no effect without COMPUTE-DEBUG-FUN.")
 129
 130 (define-optimization-quality compute-debug-fun
 131     debug
 132   ("no" "minimal" "yes" "yes"))
 133
 134 (define-optimization-quality preserve-single-use-debug-variables
 135     (if (and (>= debug 2)
 136              (< speed 3))
 137         3
 138         0)
 139   ("no" "no" "no" "yes")
 140   "When disabled, LET variable, which is never set and is referenced
 141 exactly once, is eliminated and the reference is substituted with the
 142 initial value. This allows better type inference and some algebraic
 143 optimizations.
 144
 145 When enabled, the variable is preserved and can be seen in the
 146 debugger.")
 147
 148 (define-optimization-quality insert-array-bounds-checks
 149     (if (= safety 0) 0 3)
 150   ("no" "yes" "yes" "yes"))
 151
 152 (define-optimization-quality store-xref-data
 153     (if (= space 3)
 154         0
 155         3)
 156   ("no" "yes" "yes" "yes"))
 157
 158 (define-optimization-quality store-coverage-data
 159     0
 160   ("no" "no" "yes" "yes"))