Fix a few typos, spellos, grammaros.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@14043 91177308-0d34-0410-b5e6-96231b3b80d8
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Reid Spencer 2004-06-05 14:39:24 +00:00
parent c0a2af1cf3
commit bdbcb8a260

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@ -68,12 +68,12 @@ The LLVM target-independent code generator consists of five main components:</p>
<ol> <ol>
<li><a href="#targetdesc">Abstract target description</a> interfaces which <li><a href="#targetdesc">Abstract target description</a> interfaces which
capture improtant properties about various aspects of the machine independently capture important properties about various aspects of the machine, independently
of how they will be used. These interfaces are defined in of how they will be used. These interfaces are defined in
<tt>include/llvm/Target/</tt>.</li> <tt>include/llvm/Target/</tt>.</li>
<li>Classes used to represent the <a href="#codegendesc">machine code</a> being <li>Classes used to represent the <a href="#codegendesc">machine code</a> being
generator for a target. These classes are intended to be abstract enough to generated for a target. These classes are intended to be abstract enough to
represent the machine code for <i>any</i> target machine. These classes are represent the machine code for <i>any</i> target machine. These classes are
defined in <tt>include/llvm/CodeGen/</tt>.</li> defined in <tt>include/llvm/CodeGen/</tt>.</li>
@ -99,8 +99,8 @@ Depending on which part of the code generator you are interested in working on,
different pieces of this will be useful to you. In any case, you should be different pieces of this will be useful to you. In any case, you should be
familiar with the <a href="#targetdesc">target description</a> and <a familiar with the <a href="#targetdesc">target description</a> and <a
href="#codegendesc">machine code representation</a> classes. If you want to add href="#codegendesc">machine code representation</a> classes. If you want to add
a backend for a new target, you will need <a href="#targetimpls">implement the a backend for a new target, you will need to <a href="#targetimpls">implement the
targe description</a> classes for your new target and understand the <a target description</a> classes for your new target and understand the <a
href="LangRef.html">LLVM code representation</a>. If you are interested in href="LangRef.html">LLVM code representation</a>. If you are interested in
implementing a new <a href="#codegenalgs">code generation algorithm</a>, it implementing a new <a href="#codegenalgs">code generation algorithm</a>, it
should only depend on the target-description and machine code representation should only depend on the target-description and machine code representation
@ -133,7 +133,7 @@ implements these two interfaces, and does its own thing. Another example of a
code generator like this is a (purely hypothetical) backend that converts LLVM code generator like this is a (purely hypothetical) backend that converts LLVM
to the GCC RTL form and uses GCC to emit machine code for a target.</p> to the GCC RTL form and uses GCC to emit machine code for a target.</p>
<p>The other implication of this design is that it is possible to design and <p>This design also implies that it is possible to design and
implement radically different code generators in the LLVM system that do not implement radically different code generators in the LLVM system that do not
make use of any of the built-in components. Doing so is not recommended at all, make use of any of the built-in components. Doing so is not recommended at all,
but could be required for radically different targets that do not fit into the but could be required for radically different targets that do not fit into the
@ -164,9 +164,9 @@ quality code generation for standard register-based microprocessors. Code
generation in this model is divided into the following stages:</p> generation in this model is divided into the following stages:</p>
<ol> <ol>
<li><b>Instruction Selection</b> - Determining a efficient implementation of the <li><b>Instruction Selection</b> - Determining an efficient implementation of the
input LLVM code in the target instruction set. This stage produces the initial input LLVM code in the target instruction set. This stage produces the initial
code for the program in the target instruction set the makes use of virtual code for the program in the target instruction set, then makes use of virtual
registers in SSA form and physical registers that represent any required registers in SSA form and physical registers that represent any required
register assignments due to target constraints or calling conventions.</li> register assignments due to target constraints or calling conventions.</li>
@ -191,7 +191,7 @@ elimination and stack packing.</li>
"final" machine code can go here, such as spill code scheduling and peephole "final" machine code can go here, such as spill code scheduling and peephole
optimizations.</li> optimizations.</li>
<li><b>Code Emission</b> - The final stage actually outputs the machine code for <li><b>Code Emission</b> - The final stage actually outputs the code for
the current function, either in the target assembler format or in machine the current function, either in the target assembler format or in machine
code.</li> code.</li>
@ -200,11 +200,13 @@ code.</li>
<p> <p>
The code generator is based on the assumption that the instruction selector will The code generator is based on the assumption that the instruction selector will
use an optimal pattern matching selector to create high-quality sequences of use an optimal pattern matching selector to create high-quality sequences of
native code. Alternative code generator designs based on pattern expansion and native instructions. Alternative code generator designs based on pattern
aggressive iterative peephole optimization are much slower. This design is expansion and
designed to permit efficient compilation (important for JIT environments) and aggressive iterative peephole optimization are much slower. This design
aggressive optimization (used when generate code offline) by allowing components permits efficient compilation (important for JIT environments) and
of varying levels of sophisication to be used for any step of compilation.</p> aggressive optimization (used when generating code offline) by allowing
components of varying levels of sophisication to be used for any step of
compilation.</p>
<p> <p>
In addition to these stages, target implementations can insert arbitrary In addition to these stages, target implementations can insert arbitrary
@ -253,7 +255,7 @@ as inputs or other algorithm-specific data structures).</p>
<p>All of the target description classes (except the <tt><a <p>All of the target description classes (except the <tt><a
href="#targetdata">TargetData</a></tt> class) are designed to be subclassed by href="#targetdata">TargetData</a></tt> class) are designed to be subclassed by
the concrete target implementation, and have virtual methods implemented. To the concrete target implementation, and have virtual methods implemented. To
get to these implementations, <tt><a get to these implementations, the <tt><a
href="#targetmachine">TargetMachine</a></tt> class provides accessors that href="#targetmachine">TargetMachine</a></tt> class provides accessors that
should be implemented by the target.</p> should be implemented by the target.</p>
@ -269,7 +271,7 @@ should be implemented by the target.</p>
<p>The <tt>TargetMachine</tt> class provides virtual methods that are used to <p>The <tt>TargetMachine</tt> class provides virtual methods that are used to
access the target-specific implementations of the various target description access the target-specific implementations of the various target description
classes (with the <tt>getInstrInfo</tt>, <tt>getRegisterInfo</tt>, classes (with the <tt>getInstrInfo</tt>, <tt>getRegisterInfo</tt>,
<tt>getFrameInfo</tt>, ... methods). This class is designed to be subclassed by <tt>getFrameInfo</tt>, ... methods). This class is designed to be specialized by
a concrete target implementation (e.g., <tt>X86TargetMachine</tt>) which a concrete target implementation (e.g., <tt>X86TargetMachine</tt>) which
implements the various virtual methods. The only required target description implements the various virtual methods. The only required target description
class is the <a href="#targetdata"><tt>TargetData</tt></a> class, but if the class is the <a href="#targetdata"><tt>TargetData</tt></a> class, but if the