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Fix grammar. Bold face feature points. 

llvm-svn: 68720
This commit is contained in:
Ted Kremenek 2009-04-09 18:22:40 +00:00
parent 4adfee4ff7
commit 11e13fae69
1 changed files with 7 additions and 8 deletions
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15
clang/docs/PTHInternals.html
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@ -33,9 +33,8 @@ system headers (e.g., Mac OS/X).</p>
<p>Clang supports an implementation of precompiled headers known as <p>Clang supports an implementation of precompiled headers known as
<em>pre-tokenized headers</em> (PTH). Clang's pre-tokenized headers support most <em>pre-tokenized headers</em> (PTH). Clang's pre-tokenized headers support most
of same interfaces as GCC's pre-compiled headers (as well as others) but are of same interfaces as GCC's pre-compiled headers (as well as others) but are
completely different in their implementation. This first describes the completely different in their implementation. This first describes the interface
interface for using PTH and then briefly elaborates on their design and for using PTH and then briefly elaborates on its design and implementation.</p>
implementation.</p>
<h2>Using Pretokenized Headers with <tt>clang</tt></h2> <h2>Using Pretokenized Headers with <tt>clang</tt></h2>
@ -142,13 +141,13 @@ header files was motivated by the following factors:<p>
<ul> <ul>
<li><p><em>Language independence</em>: PTH files work with any language that <li><p><b>Language independence</b>: PTH files work with any language that
Clang's lexer can handle, including C, Objective-C, and (in the early stages) Clang's lexer can handle, including C, Objective-C, and (in the early stages)
C++. This means development on language features at the parsing level or above C++. This means development on language features at the parsing level or above
(which is basically almost all interesting pieces) does not require PTH to be (which is basically almost all interesting pieces) does not require PTH to be
modified.</p></li> modified.</p></li>
<li><em>Simple design</em>: Relatively speaking, PTH has a simple design and <li><b>Simple design</b>: Relatively speaking, PTH has a simple design and
implementation, making it easy to test. Further, because the machinery for PTH implementation, making it easy to test. Further, because the machinery for PTH
resides at the lower-levels of the Clang library stack it is fairly resides at the lower-levels of the Clang library stack it is fairly
straightforward to profile and optimize.</li> straightforward to profile and optimize.</li>
@ -160,7 +159,7 @@ against) the PTH design in Clang yields several attractive features:</p>
<ul> <ul>
<li><p><em>Architecture independence</em>: In contrast to GCC's PCH files (and <li><p><b>Architecture independence</b>: In contrast to GCC's PCH files (and
those of several other compilers), Clang's PTH files are architecture those of several other compilers), Clang's PTH files are architecture
independent, requiring only a single PTH file when building an program for independent, requiring only a single PTH file when building an program for
multiple architectures.</p> multiple architectures.</p>
@ -174,7 +173,7 @@ cache of header files, a single PTH file can be safely used when compiling for
multiple architectures. This can also reduce compile times because only a single multiple architectures. This can also reduce compile times because only a single
PTH file needs to be generated during a build instead of several.</p></li> PTH file needs to be generated during a build instead of several.</p></li>
<li><p><em>Reduced memory pressure</em>: Similar to GCC, <li><p><b>Reduced memory pressure</b>: Similar to GCC,
Clang reads PTH files via the use of memory mapping (i.e., <tt>mmap</tt>). Clang reads PTH files via the use of memory mapping (i.e., <tt>mmap</tt>).
Clang, however, memory maps PTH files as read-only, meaning that multiple Clang, however, memory maps PTH files as read-only, meaning that multiple
invocations of <tt>clang-cc</tt> can share the same pages in memory from a invocations of <tt>clang-cc</tt> can share the same pages in memory from a
@ -183,7 +182,7 @@ also modifies those pages in memory, incurring the copy-on-write costs. The
read-only nature of PTH can greatly reduce memory pressure for builds involving read-only nature of PTH can greatly reduce memory pressure for builds involving
multiple cores, thus improving overall scalability.</p></li> multiple cores, thus improving overall scalability.</p></li>
<li><p><em>Fast generation</em>: PTH files can be generated in a small fraction <li><p><b>Fast generation</b>: PTH files can be generated in a small fraction
of the time needed to generate GCC's PCH files. Since PTH/PCH generation is a of the time needed to generate GCC's PCH files. Since PTH/PCH generation is a
serial operation that typically blocks progress during a build, faster serial operation that typically blocks progress during a build, faster
generation time leads to improved processor utilization with parallel builds on generation time leads to improved processor utilization with parallel builds on