[llvm-commits] [llvm] r44043 - in /llvm/trunk/docs/tutorial: LangImpl3.html LangImpl4.html LangImpl5.html

[Chris Lattner]

Author: lattner
Date: Tue Nov 13 01:06:30 2007
New Revision: 44043

URL: http://llvm.org/viewvc/llvm-project?rev=44043&view=rev
Log:
Many typos, grammaro, and wording fixes.  Patch by
Kelly Wilson, thanks!

Modified:
    llvm/trunk/docs/tutorial/LangImpl3.html
    llvm/trunk/docs/tutorial/LangImpl4.html
    llvm/trunk/docs/tutorial/LangImpl5.html

Modified: llvm/trunk/docs/tutorial/LangImpl3.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/tutorial/LangImpl3.html?rev=44043&r1=44042&r2=44043&view=diff

==============================================================================
--- llvm/trunk/docs/tutorial/LangImpl3.html (original)
+++ llvm/trunk/docs/tutorial/LangImpl3.html Tue Nov 13 01:06:30 2007
@@ -41,7 +41,7 @@
 
 <p>Welcome to Chapter 3 of the "<a href="index.html">Implementing a language
 with LLVM</a>" tutorial.  This chapter shows you how to transform the <a 
-href="LangImpl2.html">Abstract Syntax Tree built in Chapter 2</a> into LLVM IR.
+href="LangImpl2.html">Abstract Syntax Tree</a>, built in Chapter 2, into LLVM IR.
 This will teach you a little bit about how LLVM does things, as well as
 demonstrate how easy it is to use.  It's much more work to build a lexer and
 parser than it is to generate LLVM IR code. :)
@@ -79,14 +79,14 @@
 </pre>
 </div>
 
-<p>The Codegen() method says to emit IR for that AST node and all things it
+<p>The Codegen() method says to emit IR for that AST node along with all the things it
 depends on, and they all return an LLVM Value object. 
 "Value" is the class used to represent a "<a 
 href="http://en.wikipedia.org/wiki/Static_single_assignment_form">Static Single
 Assignment (SSA)</a> register" or "SSA value" in LLVM.  The most distinct aspect
 of SSA values is that their value is computed as the related instruction
 executes, and it does not get a new value until (and if) the instruction
-re-executes.  In order words, there is no way to "change" an SSA value.  For
+re-executes.  In other words, there is no way to "change" an SSA value.  For
 more information, please read up on <a 
 href="http://en.wikipedia.org/wiki/Static_single_assignment_form">Static Single
 Assignment</a> - the concepts are really quite natural once you grok them.</p>
@@ -97,7 +97,7 @@
 for our purposes, adding a virtual method is simplest.</p>
 
 <p>The
-second thing we want is an "Error" method like we used for parser, which will
+second thing we want is an "Error" method like we used for the parser, which will
 be used to report errors found during code generation (for example, use of an
 undeclared parameter):</p>
 
@@ -144,7 +144,7 @@
 
 <div class="doc_text">
 
-<p>Generating LLVM code for expression nodes is very straight-forward: less
+<p>Generating LLVM code for expression nodes is very straightforward: less
 than 45 lines of commented code for all four of our expression nodes.  First,
 we'll do numeric literals:</p>
 
@@ -174,7 +174,7 @@
 </pre>
 </div>
 
-<p>References to variables are also quite simple here.  In the simple version
+<p>References to variables are also quite simple using LLVM.  In the simple version
 of Kaleidoscope, we assume that the variable has already been emited somewhere
 and its value is available.  In practice, the only values that can be in the
 <tt>NamedValues</tt> map are function arguments.  This
@@ -211,9 +211,9 @@
 code, we do a simple switch on the opcode to create the right LLVM instruction.
 </p>
 
-<p>In this example, the LLVM builder class is starting to show its value.  
-Because it knows where to insert the newly created instruction, you just have to
-specify what instruction to create (e.g. with <tt>CreateAdd</tt>), which
+<p>In the example above, the LLVM builder class is starting to show its value.  
+LLVMBuilder knows where to insert the newly created instruction, all you have to
+do is specify what instruction to create (e.g. with <tt>CreateAdd</tt>), which
 operands to use (<tt>L</tt> and <tt>R</tt> here) and optionally provide a name
 for the generated instruction.  One nice thing about LLVM is that the name is 
 just a hint: if there are multiple additions in a single function, the first
@@ -221,17 +221,16 @@
 giving it a name like "addtmp42".  Local value names for instructions are purely
 optional, but it makes it much easier to read the IR dumps.</p>
 
-<p><a href="../LangRef.html#instref">LLVM instructions</a> are constrained with
+<p><a href="../LangRef.html#instref">LLVM instructions</a> are constrained by
 strict rules: for example, the Left and Right operators of
-an <a href="../LangRef.html#i_add">add instruction</a> have to have the same
-type, and that the result type of the add must match the operand types.  Because
+an <a href="../LangRef.html#i_add">add instruction</a> must have the same
+type, and the result type of the add must match the operand types.  Because
 all values in Kaleidoscope are doubles, this makes for very simple code for add,
 sub and mul.</p>
 
 <p>On the other hand, LLVM specifies that the <a 
 href="../LangRef.html#i_fcmp">fcmp instruction</a> always returns an 'i1' value
-(a one bit integer).  However, Kaleidoscope wants the value to be a 0.0 or 1.0
-value.  In order to get these semantics, we combine the fcmp instruction with
+(a one bit integer).  The problem with this is that Kaleidoscope wants the value to be a 0.0 or 1.0 value.  In order to get these semantics, we combine the fcmp instruction with
 a <a href="../LangRef.html#i_uitofp">uitofp instruction</a>.  This instruction
 converts its input integer into a floating point value by treating the input
 as an unsigned value.  In contrast, if we used the <a 
@@ -261,8 +260,8 @@
 </pre>
 </div>
 
-<p>Code generation for function calls is quite straight-forward with LLVM.  The
-code above first looks the name of the function up in the LLVM Module's symbol
+<p>Code generation for function calls is quite straightforward with LLVM.  The
+code above initially does a function name lookup in the LLVM Module's symbol
 table.  Recall that the LLVM Module is the container that holds all of the
 functions we are JIT'ing.  By giving each function the same name as what the
 user specifies, we can use the LLVM symbol table to resolve function names for
@@ -271,8 +270,8 @@
 <p>Once we have the function to call, we recursively codegen each argument that
 is to be passed in, and create an LLVM <a href="../LangRef.html#i_call">call
 instruction</a>.  Note that LLVM uses the native C calling conventions by
-default, allowing these calls to call into standard library functions like
-"sin" and "cos" with no additional effort.</p>
+default, allowing these calls to also call into standard library functions like
+"sin" and "cos", with no additional effort.</p>
 
 <p>This wraps up our handling of the four basic expressions that we have so far
 in Kaleidoscope.  Feel free to go in and add some more.  For example, by 
@@ -321,7 +320,7 @@
 don't "new" a type, you "get" it.</p>
 
 <p>The final line above actually creates the function that the prototype will
-correspond to.  This indicates which type, linkage, and name to use, and which
+correspond to.  This indicates the type, linkage and name to use, as well as which
 module to insert into.  "<a href="LangRef.html#linkage">external linkage</a>"
 means that the function may be defined outside the current module and/or that it
 is callable by functions outside the module.  The Name passed in is the name the
@@ -343,7 +342,7 @@
 <p>The Module symbol table works just like the Function symbol table when it
 comes to name conflicts: if a new function is created with a name was previously
 added to the symbol table, it will get implicitly renamed when added to the
-Module.  The code above exploits this fact to tell if there was a previous
+Module.  The code above exploits this fact to determine if there was a previous
 definition of this function.</p>
 
 <p>In Kaleidoscope, I choose to allow redefinitions of functions in two cases:
@@ -403,7 +402,7 @@
 </div>
 
 <p>The last bit of code for prototypes loops over all of the arguments in the
-function, setting the name of the LLVM Argument objects to match and registering
+function, setting the name of the LLVM Argument objects to match, and registering
 the arguments in the <tt>NamedValues</tt> map for future use by the
 <tt>VariableExprAST</tt> AST node.  Once this is set up, it returns the Function
 object to the caller.  Note that we don't check for conflicting 
@@ -421,8 +420,8 @@
 </pre>
 </div>
 
-<p>Code generation for function definitions starts out simply enough: first we
-codegen the prototype (Proto) and verify that it is ok.  We also clear out the
+<p>Code generation for function definitions starts out simply enough: we just
+codegen the prototype (Proto) and verify that it is ok.  We then clear out the
 <tt>NamedValues</tt> map to make sure that there isn't anything in it from the
 last function we compiled.  Code generation of the prototype ensures that there
 is an LLVM Function object that is ready to go for us.</p>
@@ -445,7 +444,7 @@
 of functions that define the <a 
 href="http://en.wikipedia.org/wiki/Control_flow_graph">Control Flow Graph</a>.
 Since we don't have any control flow, our functions will only contain one 
-block so far.  We'll fix this in <a href="LangImpl5.html">Chapter 5</a> :).</p>
+block at this point.  We'll fix this in <a href="LangImpl5.html">Chapter 5</a> :).</p>
 
 <div class="doc_code">
 <pre>
@@ -465,7 +464,7 @@
 compute the expression into the entry block and returns the value that was
 computed.  Assuming no error, we then create an LLVM <a 
 href="../LangRef.html#i_ret">ret instruction</a>, which completes the function.
-Once the function is built, we call the <tt>verifyFunction</tt> function, which
+Once the function is built, we call <tt>verifyFunction</tt>, which
 is provided by LLVM.  This function does a variety of consistency checks on the
 generated code, to determine if our compiler is doing everything right.  Using
 this is important: it can catch a lot of bugs.  Once the function is finished
@@ -481,13 +480,13 @@
 </div>
 
 <p>The only piece left here is handling of the error case.  For simplicity, we
-simply handle this by deleting the function we produced with the 
+handle this by merely deleting the function we produced with the 
 <tt>eraseFromParent</tt> method.  This allows the user to redefine a function
 that they incorrectly typed in before: if we didn't delete it, it would live in
 the symbol table, with a body, preventing future redefinition.</p>
 
-<p>This code does have a bug though.  Since the <tt>PrototypeAST::Codegen</tt>
-can return a previously defined forward declaration, this can actually delete
+<p>This code does have a bug, though.  Since the <tt>PrototypeAST::Codegen</tt>
+can return a previously defined forward declaration, our code can actually delete
 a forward declaration.  There are a number of ways to fix this bug, see what you
 can come up with!  Here is a testcase:</p>
 
@@ -571,7 +570,7 @@
 
 <p>This shows some function calls.  Note that this function will take a long
 time to execute if you call it.  In the future we'll add conditional control 
-flow to make recursion actually be useful :).</p>
+flow to actually make recursion useful :).</p>
 
 <div class="doc_code">
 <pre>
@@ -636,7 +635,7 @@
 generated.  Here you can see the big picture with all the functions referencing
 each other.</p>
 
-<p>This wraps up this chapter of the Kaleidoscope tutorial.  Up next we'll
+<p>This wraps up the third chapter of the Kaleidoscope tutorial.  Up next, we'll
 describe how to <a href="LangImpl4.html">add JIT codegen and optimizer
 support</a> to this so we can actually start running code!</p>
 

Modified: llvm/trunk/docs/tutorial/LangImpl4.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/tutorial/LangImpl4.html?rev=44043&r1=44042&r2=44043&view=diff

==============================================================================
--- llvm/trunk/docs/tutorial/LangImpl4.html (original)
+++ llvm/trunk/docs/tutorial/LangImpl4.html Tue Nov 13 01:06:30 2007
@@ -42,8 +42,8 @@
 with LLVM</a>" tutorial.  Chapters 1-3 described the implementation of a simple
 language and added support for generating LLVM IR.  This chapter describes
 two new techniques: adding optimizer support to your language, and adding JIT
-compiler support.  This shows how to get nice efficient code for your
-language.</p>
+compiler support.  These additions will demonstrate how to get nice, efficient code 
+for the Kaleidoscope language.</p>
 
 </div>
 
@@ -72,14 +72,13 @@
 </pre>
 </div>
 
-<p>This code is a very very literal transcription of the AST built by parsing
-our code, and as such, lacks optimizations like constant folding (we'd like to 
-get "<tt>add x, 3.0</tt>" in the example above) as well as other more important
-optimizations.  Constant folding in particular is a very common and very
+<p>This code is a very, very literal transcription of the AST built by parsing
+the input. As such, this transcription lacks optimizations like constant folding (we'd like to get "<tt>add x, 3.0</tt>" in the example above) as well as other more important
+optimizations.  Constant folding, in particular, is a very common and very
 important optimization: so much so that many language implementors implement
 constant folding support in their AST representation.</p>
 
-<p>With LLVM, you don't need to.  Since all calls to build LLVM IR go through
+<p>With LLVM, you don't need this support in the AST.  Since all calls to build LLVM IR go through
 the LLVM builder, it would be nice if the builder itself checked to see if there
 was a constant folding opportunity when you call it.  If so, it could just do
 the constant fold and return the constant instead of creating an instruction.
@@ -93,9 +92,9 @@
 </div>
 
 <p>All we did was switch from <tt>LLVMBuilder</tt> to 
-<tt>LLVMFoldingBuilder</tt>.  Though we change no other code, now all of our
-instructions are implicitly constant folded without us having to do anything
-about it.  For example, our example above now compiles to:</p>
+<tt>LLVMFoldingBuilder</tt>.  Though we change no other code, we now have all of our
+instructions implicitly constant folded without us having to do anything
+about it.  For example, the input above now compiles to:</p>
 
 <div class="doc_code">
 <pre>
@@ -153,7 +152,7 @@
 
 <div class="doc_text">
 
-<p>LLVM provides many optimization passes which do many different sorts of
+<p>LLVM provides many optimization passes, which do many different sorts of
 things and have different tradeoffs.  Unlike other systems, LLVM doesn't hold
 to the mistaken notion that one set of optimizations is right for all languages
 and for all situations.  LLVM allows a compiler implementor to make complete
@@ -165,7 +164,7 @@
 at link time, this can be a substantial portion of the whole program).  It also
 supports and includes "per-function" passes which just operate on a single
 function at a time, without looking at other functions.  For more information
-on passes and how the get run, see the <a href="../WritingAnLLVMPass.html">How
+on passes and how they are run, see the <a href="../WritingAnLLVMPass.html">How
 to Write a Pass</a> document and the <a href="../Passes.html">List of LLVM 
 Passes</a>.</p>
 
@@ -207,13 +206,13 @@
 </pre>
 </div>
 
-<p>This code defines two objects, a <tt>ExistingModuleProvider</tt> and a
+<p>This code defines two objects, an <tt>ExistingModuleProvider</tt> and a
 <tt>FunctionPassManager</tt>.  The former is basically a wrapper around our
 <tt>Module</tt> that the PassManager requires.  It provides certain flexibility
-that we're not going to take advantage of here, so I won't dive into what it is
-all about.</p>
+that we're not going to take advantage of here, so I won't dive into any details 
+about it.</p>
 
-<p>The meat of the matter is the definition of "<tt>OurFPM</tt>".  It
+<p>The meat of the matter here, is the definition of "<tt>OurFPM</tt>".  It
 requires a pointer to the <tt>Module</tt> (through the <tt>ModuleProvider</tt>)
 to construct itself.  Once it is set up, we use a series of "add" calls to add
 a bunch of LLVM passes.  The first pass is basically boilerplate, it adds a pass
@@ -223,7 +222,7 @@
 
 <p>In this case, we choose to add 4 optimization passes.  The passes we chose
 here are a pretty standard set of "cleanup" optimizations that are useful for
-a wide variety of code.  I won't delve into what they do, but believe me that
+a wide variety of code.  I won't delve into what they do but, believe me,
 they are a good starting place :).</p>
 
 <p>Once the PassManager is set up, we need to make use of it.  We do this by
@@ -247,7 +246,7 @@
 </pre>
 </div>
 
-<p>As you can see, this is pretty straight-forward.  The 
+<p>As you can see, this is pretty straightforward.  The 
 <tt>FunctionPassManager</tt> optimizes and updates the LLVM Function* in place,
 improving (hopefully) its body.  With this in place, we can try our test above
 again:</p>
@@ -271,7 +270,7 @@
 <p>LLVM provides a wide variety of optimizations that can be used in certain
 circumstances.  Some <a href="../Passes.html">documentation about the various 
 passes</a> is available, but it isn't very complete.  Another good source of
-ideas is to look at the passes that <tt>llvm-gcc</tt> or
+ideas can come from looking at the passes that <tt>llvm-gcc</tt> or
 <tt>llvm-ld</tt> run to get started.  The "<tt>opt</tt>" tool allows you to 
 experiment with passes from the command line, so you can see if they do
 anything.</p>
@@ -324,7 +323,7 @@
 the interpreter.</p>
 
 <p>Once the <tt>ExecutionEngine</tt> is created, the JIT is ready to be used.
-There are a variety of APIs that are useful, but the most simple one is the
+There are a variety of APIs that are useful, but the simplest one is the
 "<tt>getPointerToFunction(F)</tt>" method.  This method JIT compiles the
 specified LLVM Function and returns a function pointer to the generated machine
 code.  In our case, this means that we can change the code that parses a
@@ -353,7 +352,7 @@
 function that takes no arguments and returns the computed double.  Because the 
 LLVM JIT compiler matches the native platform ABI, this means that you can just
 cast the result pointer to a function pointer of that type and call it directly.
-As such, there is no difference between JIT compiled code and native machine
+This means, there is no difference between JIT compiled code and native machine
 code that is statically linked into your application.</p>
 
 <p>With just these two changes, lets see how Kaleidoscope works now!</p>
@@ -372,7 +371,7 @@
 
 <p>Well this looks like it is basically working.  The dump of the function
 shows the "no argument function that always returns double" that we synthesize
-for each top level expression that is typed it.  This demonstrates very basic
+for each top level expression that is typed in.  This demonstrates very basic
 functionality, but can we do more?</p>
 
 <div class="doc_code">
@@ -397,19 +396,19 @@
 </pre>
 </div>
 
-<p>This illustrates that we can now call user code, but it is a bit subtle what
-is going on here.  Note that we only invoke the JIT on the anonymous functions
-that <em>calls testfunc</em>, but we never invoked it on <em>testfunc
-itself</em>.</p>
+<p>This illustrates that we can now call user code, but there is something a bit subtle
+going on here.  Note that we only invoke the JIT on the anonymous functions
+that <em>call testfunc</em>, but we never invoked it on <em>testfunc
+</em>itself.</p>
 
-<p>What actually happened here is that the anonymous function is
+<p>What actually happened here is that the anonymous function was
 JIT'd when requested.  When the Kaleidoscope app calls through the function
 pointer that is returned, the anonymous function starts executing.  It ends up
 making the call to the "testfunc" function, and ends up in a stub that invokes
 the JIT, lazily, on testfunc.  Once the JIT finishes lazily compiling testfunc,
 it returns and the code re-executes the call.</p>
 
-<p>In summary, the JIT will lazily JIT code on the fly as it is needed.  The
+<p>In summary, the JIT will lazily JIT code, on the fly, as it is needed.  The
 JIT provides a number of other more advanced interfaces for things like freeing
 allocated machine code, rejit'ing functions to update them, etc.  However, even
 with this simple code, we get some surprisingly powerful capabilities - check

Modified: llvm/trunk/docs/tutorial/LangImpl5.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/tutorial/LangImpl5.html?rev=44043&r1=44042&r2=44043&view=diff

==============================================================================
--- llvm/trunk/docs/tutorial/LangImpl5.html (original)
+++ llvm/trunk/docs/tutorial/LangImpl5.html Tue Nov 13 01:06:30 2007
@@ -55,7 +55,7 @@
 
 <p>Welcome to Chapter 5 of the "<a href="index.html">Implementing a language
 with LLVM</a>" tutorial.  Parts 1-4 described the implementation of the simple
-Kaleidoscope language and included support for generating LLVM IR, following by
+Kaleidoscope language and included support for generating LLVM IR, followed by
 optimizations and a JIT compiler.  Unfortunately, as presented, Kaleidoscope is
 mostly useless: it has no control flow other than call and return.  This means
 that you can't have conditional branches in the code, significantly limiting its
@@ -71,13 +71,13 @@
 <div class="doc_text">
 
 <p>
-Extending Kaleidoscope to support if/then/else is quite straight-forward.  It
+Extending Kaleidoscope to support if/then/else is quite straightforward.  It
 basically requires adding lexer support for this "new" concept to the lexer,
 parser, AST, and LLVM code emitter.  This example is nice, because it shows how
 easy it is to "grow" a language over time, incrementally extending it as new
 ideas are discovered.</p>
 
-<p>Before we get going on "how" we do this extension, lets talk about what we
+<p>Before we get going on "how" we add this extension, lets talk about "what" we
 want.  The basic idea is that we want to be able to write this sort of thing:
 </p>
 
@@ -97,7 +97,7 @@
 conditional, then return the 'then' or 'else' value based on how the condition
 was resolved.  This is very similar to the C "?:" expression.</p>
 
-<p>The semantics of the if/then/else expression is that it first evaluates the
+<p>The semantics of the if/then/else expression is that it evaluates the
 condition to a boolean equality value: 0.0 is considered to be false and
 everything else is considered to be true.
 If the condition is true, the first subexpression is evaluated and returned, if
@@ -105,7 +105,7 @@
 Since Kaleidoscope allows side-effects, this behavior is important to nail down.
 </p>
 
-<p>Now that we know what we want, lets break this down into its constituent
+<p>Now that we know what we "want", lets break this down into its constituent
 pieces.</p>
 
 </div>
@@ -118,7 +118,7 @@
 
 <div class="doc_text">
 
-<p>The lexer extensions are straight-forward.  First we add new enum values
+<p>The lexer extensions are straightforward.  First we add new enum values
 for the relevant tokens:</p>
 
 <div class="doc_code">
@@ -128,7 +128,7 @@
 </pre>
 </div>
 
-<p>Once we have that, we recognize the new keywords in the lexer, pretty simple
+<p>Once we have that, we recognize the new keywords in the lexer. This is pretty simple
 stuff:</p>
 
 <div class="doc_code">
@@ -179,7 +179,7 @@
 <div class="doc_text">
 
 <p>Now that we have the relevant tokens coming from the lexer and we have the
-AST node to build, our parsing logic is relatively straight-forward.  First we
+AST node to build, our parsing logic is relatively straightforward.  First we
 define a new parsing function:</p>
 
 <div class="doc_code">
@@ -296,14 +296,14 @@
 inserting actual calls into the code and recompiling or by calling these in the
 debugger.  LLVM has many nice features for visualizing various graphs.</p>
 
-<p>Coming back to the generated code, it is fairly simple: the entry block 
+<p>Getting back to the generated code, it is fairly simple: the entry block 
 evaluates the conditional expression ("x" in our case here) and compares the
 result to 0.0 with the "<tt><a href="../LangRef.html#i_fcmp">fcmp</a> one</tt>"
 instruction ('one' is "Ordered and Not Equal").  Based on the result of this
 expression, the code jumps to either the "then" or "else" blocks, which contain
 the expressions for the true/false cases.</p>
 
-<p>Once the then/else blocks is finished executing, they both branch back to the
+<p>Once the then/else blocks are finished executing, they both branch back to the
 'ifcont' block to execute the code that happens after the if/then/else.  In this
 case the only thing left to do is to return to the caller of the function.  The
 question then becomes: how does the code know which expression to return?</p>
@@ -320,25 +320,25 @@
 value of "calltmp".  If control comes from the "else" block, it gets the value
 of "calltmp1".</p>
 
-<p>At this point, you are probably starting to think "oh no! this means my
+<p>At this point, you are probably starting to think "Oh no! This means my
 simple and elegant front-end will have to start generating SSA form in order to
 use LLVM!".  Fortunately, this is not the case, and we strongly advise
 <em>not</em> implementing an SSA construction algorithm in your front-end
 unless there is an amazingly good reason to do so.  In practice, there are two
-sorts of values that float around in code written in your average imperative
+sorts of values that float around in code written for your average imperative
 programming language that might need Phi nodes:</p>
 
 <ol>
 <li>Code that involves user variables: <tt>x = 1; x = x + 1; </tt></li>
-<li>Values that are implicit in the structure of your AST, such as the phi node
+<li>Values that are implicit in the structure of your AST, such as the Phi node
 in this case.</li>
 </ol>
 
 <p>In <a href="LangImpl7.html">Chapter 7</a> of this tutorial ("mutable 
 variables"), we'll talk about #1
 in depth.  For now, just believe me that you don't need SSA construction to
-handle them.  For #2, you have the choice of using the techniques that we will 
-describe for #1, or you can insert Phi nodes directly if convenient.  In this 
+handle this case.  For #2, you have the choice of using the techniques that we will 
+describe for #1, or you can insert Phi nodes directly, if convenient.  In this 
 case, it is really really easy to generate the Phi node, so we choose to do it
 directly.</p>
 
@@ -369,7 +369,7 @@
 </pre>
 </div>
 
-<p>This code is straight-forward and similar to what we saw before.  We emit the
+<p>This code is straightforward and similar to what we saw before.  We emit the
 expression for the condition, then compare that value to zero to get a truth
 value as a 1-bit (bool) value.</p>
 
@@ -395,7 +395,7 @@
 
 <p>Once it has that, it creates three blocks.  Note that it passes "TheFunction"
 into the constructor for the "then" block.  This causes the constructor to
-automatically insert the new block onto the end of the specified function.  The
+automatically insert the new block into the end of the specified function.  The
 other two blocks are created, but aren't yet inserted into the function.</p>
 
 <p>Once the blocks are created, we can emit the conditional branch that chooses
@@ -427,7 +427,7 @@
 block.  :)</p>
 
 <p>Once the insertion point is set, we recursively codegen the "then" expression
-from the AST.  To finish off the then block, we create an unconditional branch
+from the AST.  To finish off the "then" block, we create an unconditional branch
 to the merge block.  One interesting (and very important) aspect of the LLVM IR
 is that it <a href="../LangRef.html#functionstructure">requires all basic blocks
 to be "terminated"</a> with a <a href="../LangRef.html#terminators">control flow
@@ -439,7 +439,7 @@
 is that when we create the Phi node in the merge block, we need to set up the
 block/value pairs that indicate how the Phi will work.  Importantly, the Phi
 node expects to have an entry for each predecessor of the block in the CFG.  Why
-then are we getting the current block when we just set it to ThenBB 5 lines
+then, are we getting the current block when we just set it to ThenBB 5 lines
 above?  The problem is that the "Then" expression may actually itself change the
 block that the Builder is emitting into if, for example, it contains a nested
 "if/then/else" expression.  Because calling Codegen recursively could
@@ -492,7 +492,7 @@
 feed into the code for the top-level function, which will create the return
 instruction.</p>
 
-<p>Overall, we now have the ability to execution conditional code in
+<p>Overall, we now have the ability to execute conditional code in
 Kaleidoscope.  With this extension, Kaleidoscope is a fairly complete language
 that can calculate a wide variety of numeric functions.  Next up we'll add
 another useful expression that is familiar from non-functional languages...</p>
@@ -571,7 +571,7 @@
 
 <div class="doc_text">
 
-<p>The AST node is similarly simple.  It basically boils down to capturing
+<p>The AST node is just as simple.  It basically boils down to capturing
 the variable name and the constituent expressions in the node.</p>
 
 <div class="doc_code">
@@ -704,7 +704,7 @@
 
 <div class="doc_text">
 
-<p>The first part of codegen is very simple: we just output the start expression
+<p>The first part of Codegen is very simple: we just output the start expression
 for the loop value:</p>
 
 <div class="doc_code">
@@ -804,7 +804,7 @@
 </div>
 
 <p>Now that the body is emitted, we compute the next value of the iteration
-variable by adding the step value or 1.0 if it isn't present. '<tt>NextVar</tt>'
+variable by adding the step value, or 1.0 if it isn't present. '<tt>NextVar</tt>'
 will be the value of the loop variable on the next iteration of the loop.</p>
 
 <div class="doc_code">
@@ -839,8 +839,7 @@
 </div>
 
 <p>With the code for the body of the loop complete, we just need to finish up
-the control flow for it.  This remembers the end block (for the phi node), then
-creates the block for the loop exit ("afterloop").  Based on the value of the
+the control flow for it.  This code remembers the end block (for the phi node), then creates the block for the loop exit ("afterloop").  Based on the value of the
 exit condition, it creates a conditional branch that chooses between executing
 the loop again and exiting the loop.  Any future code is emitted in the
 "afterloop" block, so it sets the insertion position to it.</p>
@@ -869,8 +868,7 @@
 that is what we return from <tt>ForExprAST::Codegen</tt>.</p>
 
 <p>With this, we conclude the "adding control flow to Kaleidoscope" chapter of
-the tutorial.  We added two control flow constructs, and used them to motivate
-a couple of aspects of the LLVM IR that are important for front-end implementors
+the tutorial.  In this chapter we added two control flow constructs, and used them to motivate a couple of aspects of the LLVM IR that are important for front-end implementors
 to know.  In the next chapter of our saga, we will get a bit crazier and add
 <a href="LangImpl6.html">user-defined operators</a> to our poor innocent 
 language.</p>