source: trunk/essentials/dev-lang/perl/ext/B/NOTES

Last change on this file was 3181, checked in by bird, 19 years ago

perl 5.8.8
File size: 7.1 KB
Line 
1C backend invocation
2 If there are any non-option arguments, they are taken to be
3 names of objects to be saved (probably doesn't work properly yet).
4 Without extra arguments, it saves the main program.
5 -ofilename Output to filename instead of STDOUT
6 -v Verbose (currently gives a few compilation statistics)
7 -- Force end of options
8 -uPackname Force apparently unused subs from package Packname to
9 be compiled. This allows programs to use eval "foo()"
10 even when sub foo is never seen to be used at compile
11 time. The down side is that any subs which really are
12 never used also have code generated. This option is
13 necessary, for example, if you have a signal handler
14 foo which you initialise with $SIG{BAR} = "foo".
15 A better fix, though, is just to change it to
16 $SIG{BAR} = \&foo. You can have multiple -u options.
17 -D Debug options (concat or separate flags like perl -D)
18 o OPs, prints each OP as it's processed
19 c COPs, prints COPs as processed (incl. file & line num)
20 A prints AV information on saving
21 C prints CV information on saving
22 M prints MAGIC information on saving
23 -f Force optimisations on or off one at a time.
24 cog Copy-on-grow: PVs declared and initialised statically
25 no-cog No copy-on-grow
26 -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.
27 Currently, -O1 and higher set -fcog.
28
29Examples
30 perl -MO=C foo.pl > foo.c
31 perl cc_harness -o foo foo.c
32
33 perl -MO=C,-v,-DcA bar.pl > /dev/null
34
35CC backend invocation
36 If there are any non-option arguments, they are taken to be names of
37 subs to be saved. Without extra arguments, it saves the main program.
38 -ofilename Output to filename instead of STDOUT
39 -- Force end of options
40 -uPackname Force apparently unused subs from package Packname to
41 be compiled. This allows programs to use eval "foo()"
42 even when sub foo is never seen to be used at compile
43 time. The down side is that any subs which really are
44 never used also have code generated. This option is
45 necessary, for example, if you have a signal handler
46 foo which you initialise with $SIG{BAR} = "foo".
47 A better fix, though, is just to change it to
48 $SIG{BAR} = \&foo. You can have multiple -u options.
49 -mModulename Instead of generating source for a runnable executable,
50 generate source for an XSUB module. The
51 boot_Modulename function (which DynaLoader can look
52 for) does the appropriate initialisation and runs the
53 main part of the Perl source that is being compiled.
54 -pn Generate code for perl patchlevel n (e.g. 3 or 4).
55 The default is to generate C code which will link
56 with the currently executing version of perl.
57 running the perl compiler.
58 -D Debug options (concat or separate flags like perl -D)
59 r Writes debugging output to STDERR just as it's about
60 to write to the program's runtime (otherwise writes
61 debugging info as comments in its C output).
62 O Outputs each OP as it's compiled
63 s Outputs the contents of the shadow stack at each OP
64 p Outputs the contents of the shadow pad of lexicals as
65 it's loaded for each sub or the main program.
66 q Outputs the name of each fake PP function in the queue
67 as it's about to processes.
68 l Output the filename and line number of each original
69 line of Perl code as it's processed (pp_nextstate).
70 t Outputs timing information of compilation stages
71 -f Force optimisations on or off one at a time.
72 [
73 cog Copy-on-grow: PVs declared and initialised statically
74 no-cog No copy-on-grow
75 These two not in CC yet.
76 ]
77 freetmps-each-bblock Delays FREETMPS from the end of each
78 statement to the end of the each basic
79 block.
80 freetmps-each-loop Delays FREETMPS from the end of each
81 statement to the end of the group of
82 basic blocks forming a loop. At most
83 one of the freetmps-each-* options can
84 be used.
85 omit-taint Omits generating code for handling
86 perl's tainting mechanism.
87 -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.
88 Currently, -O1 sets -ffreetmps-each-bblock and -O2
89 sets -ffreetmps-each-loop.
90
91Example
92 perl -MO=CC,-O2,-ofoo.c foo.pl
93 perl cc_harness -o foo foo.c
94
95 perl -MO=CC,-mFoo,-oFoo.c Foo.pm
96 perl cc_harness -shared -c -o Foo.so Foo.c
97
98
99Bytecode backend invocation
100
101 If there are any non-option arguments, they are taken to be
102 names of objects to be saved (probably doesn't work properly yet).
103 Without extra arguments, it saves the main program.
104 -ofilename Output to filename instead of STDOUT.
105 -- Force end of options.
106 -f Force optimisations on or off one at a time.
107 Each can be preceded by no- to turn the option off.
108 compress-nullops
109 Only fills in the necessary fields of ops which have
110 been optimised away by perl's internal compiler.
111 omit-sequence-numbers
112 Leaves out code to fill in the op_seq field of all ops
113 which is only used by perl's internal compiler.
114 bypass-nullops
115 If op->op_next ever points to a NULLOP, replaces the
116 op_next field with the first non-NULLOP in the path
117 of execution.
118 strip-syntax-tree
119 Leaves out code to fill in the pointers which link the
120 internal syntax tree together. They're not needed at
121 run-time but leaving them out will make it impossible
122 to recompile or disassemble the resulting program.
123 It will also stop "goto label" statements from working.
124 -On Optimisation level (n = 0, 1, 2, ...). -O means -O1.
125 -O1 sets -fcompress-nullops -fomit-sequence numbers.
126 -O6 adds -fstrip-syntax-tree.
127 -D Debug options (concat or separate flags like perl -D)
128 o OPs, prints each OP as it's processed.
129 b print debugging information about bytecompiler progress
130 a tells the assembler to include source assembler lines
131 in its output as bytecode comments.
132 C prints each CV taken from the final symbol tree walk.
133 -S Output assembler source rather than piping it
134 through the assembler and outputting bytecode.
135 -m Compile as a module rather than a standalone program.
136 Currently this just means that the bytecodes for
137 initialising main_start, main_root and curpad are
138 omitted.
139
140Example
141 perl -MO=Bytecode,-O6,-o,foo.plc foo.pl
142
143 perl -MO=Bytecode,-S foo.pl > foo.S
144 assemble foo.S > foo.plc
145 byteperl foo.plc
146
147 perl -MO=Bytecode,-m,-oFoo.pmc Foo.pm
148
149Backends for debugging
150 perl -MO=Terse,exec foo.pl
151 perl -MO=Debug bar.pl
152
153O module
154 Used with "perl -MO=Backend,foo,bar prog.pl" to invoke the backend
155 B::Backend with options foo and bar. O invokes the sub
156 B::Backend::compile() with arguments foo and bar at BEGIN time.
157 That compile() sub must do any inital argument processing replied.
158 If unsuccessful, it should return a string which O arranges to be
159 printed as an error message followed by a clean error exit. In the
160 normal case where any option processing in compile() is successful,
161 it should return a sub ref (usually a closure) to perform the
162 actual compilation. When O regains control, it ensures that the
163 "-c" option is forced (so that the program being compiled doesn't
164 end up running) and registers a CHECK block to call back the sub ref
165 returned from the backend's compile(). Perl then continues by
166 parsing prog.pl (just as it would with "perl -c prog.pl") and after
167 doing so, assuming there are no parse-time errors, the CHECK block
168 of O gets called and the actual backend compilation happens. Phew.
Note: See TracBrowser for help on using the repository browser.