xref: /llvm-project/llvm/docs/CommandGuide/lli.rst (revision 771613295d92d4e810351863390b5a870d09d278)
1lli - directly execute programs from LLVM bitcode
2=================================================
3
4.. program:: lli
5
6SYNOPSIS
7--------
8
9:program:`lli` [*options*] [*filename*] [*program args*]
10
11DESCRIPTION
12-----------
13
14:program:`lli` directly executes programs in LLVM bitcode format.  It takes a program
15in LLVM bitcode format and executes it using a just-in-time compiler or an
16interpreter.
17
18:program:`lli` is *not* an emulator. It will not execute IR of different architectures
19and it can only interpret (or JIT-compile) for the host architecture.
20
21The JIT compiler takes the same arguments as other tools, like :program:`llc`,
22but they don't necessarily work for the interpreter.
23
24If `filename` is not specified, then :program:`lli` reads the LLVM bitcode for the
25program from standard input.
26
27The optional *args* specified on the command line are passed to the program as
28arguments.
29
30GENERAL OPTIONS
31---------------
32
33.. option:: -fake-argv0=executable
34
35 Override the ``argv[0]`` value passed into the executing program.
36
37.. option:: -force-interpreter={false,true}
38
39 If set to true, use the interpreter even if a just-in-time compiler is available
40 for this architecture. Defaults to false.
41
42.. option:: -help
43
44 Print a summary of command line options.
45
46.. option:: -load=pluginfilename
47
48 Causes :program:`lli` to load the plugin (shared object) named *pluginfilename* and use
49 it for optimization.
50
51.. option:: -stats
52
53 Print statistics from the code-generation passes. This is only meaningful for
54 the just-in-time compiler, at present.
55
56.. option:: -time-passes
57
58 Record the amount of time needed for each code-generation pass and print it to
59 standard error.
60
61.. option:: -version
62
63 Print out the version of :program:`lli` and exit without doing anything else.
64
65TARGET OPTIONS
66--------------
67
68.. option:: -mtriple=target triple
69
70 Override the target triple specified in the input bitcode file with the
71 specified string.  This may result in a crash if you pick an
72 architecture which is not compatible with the current system.
73
74.. option:: -march=arch
75
76 Specify the architecture for which to generate assembly, overriding the target
77 encoded in the bitcode file.  See the output of **llc -help** for a list of
78 valid architectures.  By default this is inferred from the target triple or
79 autodetected to the current architecture.
80
81.. option:: -mcpu=cpuname
82
83 Specify a specific chip in the current architecture to generate code for.
84 By default this is inferred from the target triple and autodetected to
85 the current architecture.  For a list of available CPUs, use:
86 **llvm-as < /dev/null | llc -march=xyz -mcpu=help**
87
88.. option:: -mattr=a1,+a2,-a3,...
89
90 Override or control specific attributes of the target, such as whether SIMD
91 operations are enabled or not.  The default set of attributes is set by the
92 current CPU.  For a list of available attributes, use:
93 **llvm-as < /dev/null | llc -march=xyz -mattr=help**
94
95FLOATING POINT OPTIONS
96----------------------
97
98.. option:: -disable-excess-fp-precision
99
100 Disable optimizations that may increase floating point precision.
101
102.. option:: -enable-no-infs-fp-math
103
104 Enable optimizations that assume no Inf values.
105
106.. option:: -enable-no-nans-fp-math
107
108 Enable optimizations that assume no NAN values.
109
110.. option:: -enable-unsafe-fp-math
111
112 Causes :program:`lli` to enable optimizations that may decrease floating point
113 precision.
114
115.. option:: -soft-float
116
117 Causes :program:`lli` to generate software floating point library calls instead of
118 equivalent hardware instructions.
119
120CODE GENERATION OPTIONS
121-----------------------
122
123.. option:: -code-model=model
124
125 Choose the code model from:
126
127 .. code-block:: text
128
129      default: Target default code model
130      tiny: Tiny code model
131      small: Small code model
132      kernel: Kernel code model
133      medium: Medium code model
134      large: Large code model
135
136.. option:: -disable-post-RA-scheduler
137
138 Disable scheduling after register allocation.
139
140.. option:: -disable-spill-fusing
141
142 Disable fusing of spill code into instructions.
143
144.. option:: -jit-enable-eh
145
146 Exception handling should be enabled in the just-in-time compiler.
147
148.. option:: -join-liveintervals
149
150 Coalesce copies (default=true).
151
152.. option:: -nozero-initialized-in-bss
153
154  Don't place zero-initialized symbols into the BSS section.
155
156.. option:: -pre-RA-sched=scheduler
157
158 Instruction schedulers available (before register allocation):
159
160 .. code-block:: text
161
162      =default: Best scheduler for the target
163      =none: No scheduling: breadth first sequencing
164      =simple: Simple two pass scheduling: minimize critical path and maximize processor utilization
165      =simple-noitin: Simple two pass scheduling: Same as simple except using generic latency
166      =list-burr: Bottom-up register reduction list scheduling
167      =list-tdrr: Top-down register reduction list scheduling
168      =list-td: Top-down list scheduler
169
170.. option:: -regalloc=allocator
171
172 Register allocator to use (default=linearscan)
173
174 .. code-block:: text
175
176      =bigblock: Big-block register allocator
177      =linearscan: linear scan register allocator
178      =local: local register allocator
179      =simple: simple register allocator
180
181.. option:: -relocation-model=model
182
183 Choose relocation model from:
184
185 .. code-block:: text
186
187      =default: Target default relocation model
188      =static: Non-relocatable code
189      =pic: Fully relocatable, position independent code
190      =dynamic-no-pic: Relocatable external references, non-relocatable code
191
192.. option:: -spiller
193
194 Spiller to use (default=local)
195
196 .. code-block:: text
197
198      =simple: simple spiller
199      =local: local spiller
200
201.. option:: -x86-asm-syntax=syntax
202
203 Choose style of code to emit from X86 backend:
204
205 .. code-block:: text
206
207      =att: Emit AT&T-style assembly
208      =intel: Emit Intel-style assembly
209
210EXIT STATUS
211-----------
212
213If :program:`lli` fails to load the program, it will exit with an exit code of 1.
214Otherwise, it will return the exit code of the program it executes.
215
216SEE ALSO
217--------
218
219:manpage:`llc(1)`
220