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Improving lli documentation

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Too many people hope lli would act as an emulator when it's actually
just a tool to help prototype IR code and test the JIT compiler. This
commit makes that fact explicit in the documentation

It also migrates the old style bold/italic doc tags to the preferred
meta tags (.. option::, :program:, etc).

No errors when generating the documents, visual inspection in the HTML
result doesn't show any major difference, apart from the slight style
change.

llvm-svn: 243401
This commit is contained in:
Renato Golin 2015-07-28 10:24:11 +00:00
parent 07f74e1a99
commit babd40ed93
1 changed files with 44 additions and 124 deletions
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docs/CommandGuide/lli.rst
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@ -1,172 +1,127 @@
lli - directly execute programs from LLVM bitcode
=================================================
SYNOPSIS
--------
**lli** [*options*] [*filename*] [*program args*]
:program:`lli` [*options*] [*filename*] [*program args*]
DESCRIPTION
-----------
:program:`lli` directly executes programs in LLVM bitcode format. It takes a program
in LLVM bitcode format and executes it using a just-in-time compiler or an
interpreter.
**lli** directly executes programs in LLVM bitcode format. It takes a program
in LLVM bitcode format and executes it using a just-in-time compiler, if one is
available for the current architecture, or an interpreter. **lli** takes all of
the same code generator options as llc|llc, but they are only effective when
**lli** is using the just-in-time compiler.
:program:`lli` is *not* an emulator. It will not execute IR of different architectures
and it can only interpret (or JIT-compile) for the host architecture.
If *filename* is not specified, then **lli** reads the LLVM bitcode for the
The JIT compiler takes the same arguments as other tools, like :program:`llc`,
but they don't necessarily work for the interpreter.
If `filename` is not specified, then :program:`lli` reads the LLVM bitcode for the
program from standard input.
The optional *args* specified on the command line are passed to the program as
arguments.
GENERAL OPTIONS
---------------
**-fake-argv0**\ =\ *executable*
.. option:: -fake-argv0=executable
Override the ``argv[0]`` value passed into the executing program.
**-force-interpreter**\ =\ *{false,true}*
.. option:: -force-interpreter={false,true}
If set to true, use the interpreter even if a just-in-time compiler is available
for this architecture. Defaults to false.
**-help**
.. option:: -help
Print a summary of command line options.
.. option:: -load=pluginfilename
**-load**\ =\ *pluginfilename*
Causes **lli** to load the plugin (shared object) named *pluginfilename* and use
Causes :program:`lli` to load the plugin (shared object) named *pluginfilename* and use
it for optimization.
**-stats**
.. option:: -stats
Print statistics from the code-generation passes. This is only meaningful for
the just-in-time compiler, at present.
**-time-passes**
.. option:: -time-passes
Record the amount of time needed for each code-generation pass and print it to
standard error.
.. option:: -version
**-version**
Print out the version of **lli** and exit without doing anything else.
Print out the version of :program:`lli` and exit without doing anything else.
TARGET OPTIONS
--------------
**-mtriple**\ =\ *target triple*
.. option:: -mtriple=target triple
Override the target triple specified in the input bitcode file with the
specified string. This may result in a crash if you pick an
architecture which is not compatible with the current system.
**-march**\ =\ *arch*
.. option:: -march=arch
Specify the architecture for which to generate assembly, overriding the target
encoded in the bitcode file. See the output of **llc -help** for a list of
valid architectures. By default this is inferred from the target triple or
autodetected to the current architecture.
**-mcpu**\ =\ *cpuname*
.. option:: -mcpu=cpuname
Specify a specific chip in the current architecture to generate code for.
By default this is inferred from the target triple and autodetected to
the current architecture. For a list of available CPUs, use:
**llvm-as < /dev/null | llc -march=xyz -mcpu=help**
**-mattr**\ =\ *a1,+a2,-a3,...*
.. option:: -mattr=a1,+a2,-a3,...
Override or control specific attributes of the target, such as whether SIMD
operations are enabled or not. The default set of attributes is set by the
current CPU. For a list of available attributes, use:
**llvm-as < /dev/null | llc -march=xyz -mattr=help**
FLOATING POINT OPTIONS
----------------------
**-disable-excess-fp-precision**
.. option:: -disable-excess-fp-precision
Disable optimizations that may increase floating point precision.
**-enable-no-infs-fp-math**
.. option:: -enable-no-infs-fp-math
Enable optimizations that assume no Inf values.
**-enable-no-nans-fp-math**
.. option:: -enable-no-nans-fp-math
Enable optimizations that assume no NAN values.
.. option:: -enable-unsafe-fp-math
**-enable-unsafe-fp-math**
Causes **lli** to enable optimizations that may decrease floating point
Causes :program:`lli` to enable optimizations that may decrease floating point
precision.
.. option:: -soft-float
**-soft-float**
Causes **lli** to generate software floating point library calls instead of
Causes :program:`lli` to generate software floating point library calls instead of
equivalent hardware instructions.
CODE GENERATION OPTIONS
-----------------------
**-code-model**\ =\ *model*
.. option:: -code-model=model
Choose the code model from:
.. code-block:: perl
default: Target default code model
@ -175,42 +130,30 @@ CODE GENERATION OPTIONS
medium: Medium code model
large: Large code model
**-disable-post-RA-scheduler**
.. option:: -disable-post-RA-scheduler
Disable scheduling after register allocation.
**-disable-spill-fusing**
.. option:: -disable-spill-fusing
Disable fusing of spill code into instructions.
**-jit-enable-eh**
.. option:: -jit-enable-eh
Exception handling should be enabled in the just-in-time compiler.
**-join-liveintervals**
.. option:: -join-liveintervals
Coalesce copies (default=true).
.. option:: -nozero-initialized-in-bss
Don't place zero-initialized symbols into the BSS section.
**-nozero-initialized-in-bss** Don't place zero-initialized symbols into the BSS section.
**-pre-RA-sched**\ =\ *scheduler*
.. option:: -pre-RA-sched=scheduler
Instruction schedulers available (before register allocation):
.. code-block:: perl
=default: Best scheduler for the target
@ -221,74 +164,51 @@ CODE GENERATION OPTIONS
=list-tdrr: Top-down register reduction list scheduling
=list-td: Top-down list scheduler -print-machineinstrs - Print generated machine code
**-regalloc**\ =\ *allocator*
.. option:: -regalloc=allocator
Register allocator to use (default=linearscan)
.. code-block:: perl
=bigblock: Big-block register allocator
=linearscan: linear scan register allocator =local - local register allocator
=simple: simple register allocator
**-relocation-model**\ =\ *model*
.. option:: -relocation-model=model
Choose relocation model from:
.. code-block:: perl
=default: Target default relocation model
=static: Non-relocatable code =pic - Fully relocatable, position independent code
=dynamic-no-pic: Relocatable external references, non-relocatable code
**-spiller**
.. option:: -spiller
Spiller to use (default=local)
.. code-block:: perl
=simple: simple spiller
=local: local spiller
**-x86-asm-syntax**\ =\ *syntax*
.. option:: -x86-asm-syntax=syntax
Choose style of code to emit from X86 backend:
.. code-block:: perl
=att: Emit AT&T-style assembly
=intel: Emit Intel-style assembly
EXIT STATUS
-----------
If **lli** fails to load the program, it will exit with an exit code of 1.
If :program:`lli` fails to load the program, it will exit with an exit code of 1.
Otherwise, it will return the exit code of the program it executes.
SEE ALSO
--------
llc|llc
:program:`llc`