+

Now that we have a way to compile our new pass, we just have to write it. Start out with: -+ + #include "llvm/Pass.h" #include "llvm/Function.h" - +#include "llvm/Support/raw_ostream.h" + +

Which are needed because we are writing a Pass, and +href="http://llvm.org/doxygen/classllvm_1_1Pass.html">Pass, we are operating on Function's.

+href="http://llvm.org/doxygen/classllvm_1_1Function.html">Function's, +and we will be doing some printing.

Next we have:

+
+
+ using namespace llvm;
-
+

... which is required because the functions from the include files -live in the llvm namespace. -

+live in the llvm namespace.

Next we have:

+
+ namespace {
-
+

... which starts out an anonymous namespace. Anonymous namespaces are to C++ what the "static" keyword is to C (at global scope). It makes the -things declared inside of the anonymous namespace only visible to the current +things declared inside of the anonymous namespace visible only to the current file. If you're not familiar with them, consult a decent C++ book for more information.

Next, we declare our pass itself:

+
+   struct Hello : public FunctionPass {
-

+

This declares a "Hello" class that is a subclass of FunctionPass. The different builtin pass subclasses are described in detail later, but for now, know that FunctionPass's operate a function at a +href="#FunctionPass">FunctionPass's operate on a function at a time.

-     static char ID;
-     Hello() : FunctionPass((intptr_t)&ID) {}
-

+    static char ID;
+    Hello() : FunctionPass(ID) {}
+

This declares pass identifier used by LLVM to identify pass. This allows LLVM to -avoid using expensive C++ runtime information.

This declares pass identifier used by LLVM to identify pass. This allows LLVM +to avoid using expensive C++ runtime information.

+
+     virtual bool runOnFunction(Function &F) {
-      llvm::cerr << "Hello: " << F.getName() << "\n";
+      errs() << "Hello: ";
+      errs().write_escaped(F.getName()) << "\n";
       return false;
     }
   };  // end of struct Hello
-
+}  // end of anonymous namespace
+

We declare a "runOnFunction" method, which overloads an abstract virtual method inherited from FunctionPass. This is where we are supposed to do our thing, so we just print out our message with the name of each function.

-  char Hello::ID = 0;
-

+char Hello::ID = 0;
+

We initialize pass ID here. LLVM uses ID's address to identify pass so +

We initialize pass ID here. LLVM uses ID's address to identify a pass, so initialization value is not important.

-  RegisterPass<Hello> X("hello", "Hello World Pass");
-}  // end of anonymous namespace
-

+static RegisterPass<Hello> X("hello", "Hello World Pass",
+                             false /* Only looks at CFG */,
+                             false /* Analysis Pass */);
+

Lastly, we register our class Hello, -giving it a command line -argument "hello", and a name "Hello World Pass".

Lastly, we register our class Hello, +giving it a command line argument "hello", and a name "Hello World +Pass". The last two arguments describe its behavior: if a pass walks CFG +without modifying it then the third argument is set to true; if a pass +is an analysis pass, for example dominator tree pass, then true is +supplied as the fourth argument.

As a whole, the .cpp file looks like:

+
+ #include "llvm/Pass.h"
 #include "llvm/Function.h"
+#include "llvm/Support/raw_ostream.h"
 
 using namespace llvm;
 
@@ -312,47 +347,52 @@ argument "hello", and a name "Hello World Pass".
   struct Hello : public FunctionPass {
     
     static char ID;
-    Hello() : FunctionPass((intptr_t)&ID) {}
+    Hello() : FunctionPass(ID) {}
 
     virtual bool runOnFunction(Function &F) {
-      llvm::cerr << "Hello: " << F.getName() << "\n";
+      errs() << "Hello: ";
+      errs().write_escaped(F.getName()) << '\n';
       return false;
     }
+
   };
-  
-  RegisterPass<Hello> X("hello", "Hello World Pass");
 }
-
+  
+char Hello::ID = 0;
+static RegisterPass<Hello> X("hello", "Hello World Pass", false, false);
+

Now that it's all together, compile the file with a simple "gmake" -command in the local directory and you should get a new -"Debug/lib/Hello.so file. Note that everything in this file is -contained in an anonymous namespace: this reflects the fact that passes are self -contained units that do not need external interfaces (although they can have -them) to be useful.

+command in the local directory and you should get a new file +"Debug+Asserts/lib/Hello.so" under the top level directory of the LLVM +source tree (not in the local directory). Note that everything in this file is +contained in an anonymous namespace — this reflects the fact that passes +are self contained units that do not need external interfaces (although they can +have them) to be useful.

Running a pass with `opt` -

+ -

Now that you have a brand new shiny shared object file, we can use the opt command to run an LLVM program through your pass. Because you -registered your pass with the RegisterPass template, you will be able to +registered your pass with RegisterPass, you will be able to use the opt tool to access it, once loaded.

To test it, follow the example at the end of the Getting Started Guide to compile "Hello World" to -LLVM. We can now run the bytecode file (hello.bc) for the program -through our transformation like this (or course, any bytecode file will +LLVM. We can now run the bitcode file (hello.bc) for the program +through our transformation like this (or course, any bitcode file will work):

-$ opt -load ../../../Debug/lib/Hello.so -hello < hello.bc > /dev/null
+$ opt -load ../../../Debug+Asserts/lib/Hello.so -hello < hello.bc > /dev/null
 Hello: __main
 Hello: puts
 Hello: main
@@ -366,13 +406,13 @@ interesting way, we just throw away the result of opt (sending it to
 /dev/null).
 
 To see what happened to the other string you registered, try running
-opt with the --help option:
+opt with the -help option:
 
 -$ opt -load ../../../Debug/lib/Hello.so --help
+$ opt -load ../../../Debug+Asserts/lib/Hello.so -help
 OVERVIEW: llvm .bc -> .bc modular optimizer
 
-USAGE: opt [options] <input bytecode>
+USAGE: opt [options] <input bitcode>
 
 OPTIONS:
   Optimizations available:
@@ -397,7 +437,7 @@ the execution time of your pass along with the other passes you queue up.  For
 example:
 
 -$ opt -load ../../../Debug/lib/Hello.so -hello -time-passes < hello.bc > /dev/null
+$ opt -load ../../../Debug+Asserts/lib/Hello.so -hello -time-passes < hello.bc > /dev/null
 Hello: __main
 Hello: puts
 Hello: main
@@ -407,7 +447,7 @@ Hello: main
   Total Execution Time: 0.02 seconds (0.0479059 wall clock)
 
    ---User Time---   --System Time--   --User+System--   ---Wall Time---  --- Pass Name ---
-   0.0100 (100.0%)   0.0000 (  0.0%)   0.0100 ( 50.0%)   0.0402 ( 84.0%)  Bytecode Writer
+   0.0100 (100.0%)   0.0000 (  0.0%)   0.0100 ( 50.0%)   0.0402 ( 84.0%)  Bitcode Writer
    0.0000 (  0.0%)   0.0100 (100.0%)   0.0100 ( 50.0%)   0.0031 (  6.4%)  Dominator Set Construction
    0.0000 (  0.0%)   0.0000 (  0.0%)   0.0000 (  0.0%)   0.0013 (  2.7%)  Module Verifier
    0.0000 (  0.0%)   0.0000 (  0.0%)   0.0000 (  0.0%)   0.0033 (  6.9%)  Hello World Pass
@@ -424,13 +464,15 @@ about some more details of how they work and how to use them.
 
 
 
+
+
 
-
+
   Pass classes and requirements
-
+
 
 
-
+
 
 One of the first things that you should do when designing a new pass is to
 decide what class you should subclass for your pass.  The 
 
When choosing a superclass for your Pass, you should choose the most
 specific class possible, while still being able to meet the requirements
 listed.  This gives the LLVM Pass Infrastructure information necessary to
-optimize how passes are run, so that the resultant compiler isn't unneccesarily
+optimize how passes are run, so that the resultant compiler isn't unnecessarily
 slow.

 
-

-
 
-
+
   The ImmutablePass class
-
+
 
-
+
 
 The most plain and boring type of pass is the "ImmutablePass"
@@ -471,34 +511,38 @@ invalidated, and are never "run".
 
 
 
-
+
   The ModulePass class
-
+
 
-
+
 
 The "ModulePass"
 class is the most general of all superclasses that you can use.  Deriving from
 ModulePass indicates that your pass uses the entire program as a unit,
-refering to function bodies in no predictable order, or adding and removing
+referring to function bodies in no predictable order, or adding and removing
 functions.  Because nothing is known about the behavior of ModulePass
-subclasses, no optimization can be done for their execution. A module pass
-can use function level passes (e.g. dominators) using getAnalysis interface
- getAnalysis<DominatorTree>(Function).  
+subclasses, no optimization can be done for their execution.
+
+A module pass can use function level passes (e.g. dominators) using
+the getAnalysis interface
+getAnalysis<DominatorTree>(llvm::Function *) to provide the
+function to retrieve analysis result for, if the function pass does not require
+any module or immutable passes. Note that this can only be done for functions for which the
+analysis ran, e.g. in the case of dominators you should only ask for the
+DominatorTree for function definitions, not declarations.
 
 To write a correct ModulePass subclass, derive from
 ModulePass and overload the runOnModule method with the
 following signature:
 
-
-
 
-
+
   The runOnModule method
-
+
 
-
+
 
    virtual bool runOnModule(Module &M) = 0;
@@ -510,12 +554,14 @@ false otherwise.
 
 
 
+
+
 
-
+
   The CallGraphSCCPass class
-
+
 
-
+
 
 The "CallGraphSCCPass"
@@ -534,11 +580,9 @@ href="#BasicBlockPass">BasicBlockPass, you should derive from
 
 

 
-... not allowed to modify any Functions that are not in
-the current SCC.
-
-... not allowed to inspect any Function's other than those in the
-current SCC and the direct callees of the SCC.
+... not allowed to inspect or modify any Functions other
+than those in the current SCC and the direct callers and direct callees of the
+SCC.
 
 ... required to preserve the current CallGraph object, updating it
 to reflect any changes made to the program.
@@ -558,15 +602,14 @@ because it has to handle SCCs with more than one node in it.  All of the virtual
 methods described below should return true if they modified the program, or
 false if they didn't.
 
-
-
 
-
-  The doInitialization(CallGraph &)
-  method
-
+
+  
+    The doInitialization(CallGraph &) method
+  
+
 
-
+
 
    virtual bool doInitialization(CallGraph &CG);
@@ -583,14 +626,14 @@ fast).
 
 
 
-
+
   The runOnSCC method
-
+
 
-
+
 
 -  virtual bool runOnSCC(const std::vector<CallGraphNode *> &SCCM) = 0;
+  virtual bool runOnSCC(CallGraphSCC &SCC) = 0;
 
 
 The runOnSCC method performs the interesting work of the pass, and
@@ -600,12 +643,13 @@ otherwise.
 
 
 
-
-  The doFinalization(CallGraph
-   &) method
-
+
+  
+    The doFinalization(CallGraph &) method
+  
+
 
-
+
 
    virtual bool doFinalization(CallGraph &CG);
@@ -618,12 +662,14 @@ program being compiled.
 
 
 
+
+
 
-
+
   The FunctionPass class
-
+
 
-
+
 
 In contrast to ModulePass subclasses, FunctionPass
@@ -648,15 +694,14 @@ href="#basiccode">Hello World pass for example).  FunctionPass's
 may overload three virtual methods to do their work.  All of these methods
 should return true if they modified the program, or false if they didn't.
 
-
-
 
-
-  The doInitialization(Module &)
-  method
-
+
+  
+    The doInitialization(Module &) method
+  
+
 
-
+
 
    virtual bool doInitialization(Module &M);
@@ -680,11 +725,11 @@ free functions that it needs, adding prototypes to the module if necessary.
 
 
 
-
+
   The runOnFunction method
-
+
 
-
+
 
    virtual bool runOnFunction(Function &F) = 0;
@@ -697,12 +742,13 @@ be returned if the function is modified.
 
 
 
-
-  The doFinalization(Module
-  &) method
-
+
+  
+    The doFinalization(Module &) method
+  
+
 
-
+
 
    virtual bool doFinalization(Module &M);
@@ -715,12 +761,14 @@ program being compiled.
 
 
 
+
+
 
-
+
   The LoopPass class 
-
+
 
-
+
 
  All LoopPass execute on each loop in the function independent of
 all of the other loops in the function. LoopPass processes loops in
@@ -728,19 +776,18 @@ loop nest order such that outer most loop is processed last. 
 
  LoopPass subclasses are allowed to update loop nest using
 LPPassManager interface. Implementing a loop pass is usually
-straightforward. Looppass's may overload three virtual methods to
+straightforward. LoopPass's may overload three virtual methods to
 do their work. All these methods should return true if they modified the 
 program, or false if they didn't. 
-
 
 
-
-  The doInitialization(Loop *,
-                                                 LPPassManager &)
-  method
-
+
+  
+    The doInitialization(Loop *,LPPassManager &) method
+  
+
 
-
+
 
    virtual bool doInitialization(Loop *, LPPassManager &LPM);
@@ -757,11 +804,11 @@ information.
 
 
 
-
+
   The runOnLoop method
-
+
 
-
+
 
    virtual bool runOnLoop(Loop *, LPPassManager &LPM) = 0;
@@ -775,11 +822,11 @@ should be used to update loop nest.
 
 
 
-
+
   The doFinalization() method
-
+
 
-
+
 
    virtual bool doFinalization();
@@ -792,14 +839,93 @@ program being compiled. 
 
 
 
+
 
+
+
+  The RegionPass class 
+
+
+
+
+ RegionPass is similar to LoopPass,
+but executes on each single entry single exit region in the function.
+RegionPass processes regions in nested order such that the outer most
+region is processed last.  
+
+ RegionPass subclasses are allowed to update the region tree by using
+the RGPassManager interface. You may overload three virtual methods of
+RegionPass to implement your own region pass. All these
+methods should return true if they modified the program, or false if they didn not.
+
+
+
+
+  
+    The doInitialization(Region *, RGPassManager &) method
+  
+
+
+
+
++  virtual bool doInitialization(Region *, RGPassManager &RGM);
+
+
+The doInitialization method is designed to do simple initialization
+type of stuff that does not depend on the functions being processed.  The
+doInitialization method call is not scheduled to overlap with any
+other pass executions (thus it should be very fast). RPPassManager
+interface should be used to access Function or Module level analysis
+information.
+
+
+
+
+
+
+  The runOnRegion method
+
+
+
+
++  virtual bool runOnRegion(Region *, RGPassManager &RGM) = 0;
+

+
+
The runOnRegion method must be implemented by your subclass to do
+the transformation or analysis work of your pass.  As usual, a true value should
+be returned if the region is modified. RGPassManager interface
+should be used to update region tree.
+
+
+
+
+
+  The doFinalization() method
+
+
+
+
++  virtual bool doFinalization();
+
+
+The doFinalization method is an infrequently used method that is
+called when the pass framework has finished calling runOnRegion for every region in the
+program being compiled. 
+
+
+
+
 
 
-
+
   The BasicBlockPass class
-
+
 
-
+
 
 BasicBlockPass's are just like FunctionPass's, except that they must limit
@@ -821,15 +947,14 @@ href="#doInitialization_mod">doInitialization(Module &) and doFinalization(Module &) methods that FunctionPass's have, but also have the following virtual methods that may also be implemented:
 
-
-
 
-
-  The doInitialization(Function
-  &) method
-
+
+  
+    The doInitialization(Function &) method
+  
+
 
-
+
 
    virtual bool doInitialization(Function &F);
@@ -846,11 +971,11 @@ fast).
 
 
 
-
+
   The runOnBasicBlock method
-
+
 
-
+
 
    virtual bool runOnBasicBlock(BasicBlock &BB) = 0;
@@ -864,12 +989,13 @@ if the basic block is modified.
 
 
 
-
-  The doFinalization(Function &) 
-  method
-
+
+  
+    The doFinalization(Function &) method
+  
+
 
-
+
 
    virtual bool doFinalization(Function &F);
@@ -883,39 +1009,46 @@ finalization.
 
 
 
+
+
 
-
+
   The MachineFunctionPass class
-
+
 
-
+
 
 A MachineFunctionPass is a part of the LLVM code generator that
 executes on the machine-dependent representation of each LLVM function in the
-program.  A MachineFunctionPass is also a FunctionPass, so all
+program.
+
+Code generator passes are registered and initialized specially by
+TargetMachine::addPassesToEmitFile and similar routines, so they
+cannot generally be run from the opt or bugpoint
+commands.
+
+A MachineFunctionPass is also a FunctionPass, so all
 the restrictions that apply to a FunctionPass also apply to it.
 MachineFunctionPasses also have additional restrictions. In particular,
 MachineFunctionPasses are not allowed to do any of the following:
 
 
-Modify any LLVM Instructions, BasicBlocks or Functions.
+Modify or create any LLVM IR Instructions, BasicBlocks, Arguments,
+    Functions, GlobalVariables, GlobalAliases, or Modules.
 Modify a MachineFunction other than the one currently being processed.
-Add or remove MachineFunctions from the current Module.
-Add or remove global variables from the current Module.
 Maintain state across invocations of runOnMachineFunction (including global
 data)
 
 
-
-
 
-
-  The runOnMachineFunction(MachineFunction
-  &MF) method
-
+
+  
+    The runOnMachineFunction(MachineFunction &MF) method
+  
+
 
-
+
 
    virtual bool runOnMachineFunction(MachineFunction &MF) = 0;
@@ -936,41 +1069,42 @@ remember, you may not modify the LLVM Function or its contents from a
 
 
 
+
+
+
+
 
-
+
   Pass registration
-
+
 
 
-
+
 
 In the Hello World example pass we illustrated how
 pass registration works, and discussed some of the reasons that it is used and
 what it does.  Here we discuss how and why passes are registered.
 
 As we saw above, passes are registered with the RegisterPass
-template, which requires you to pass at least two
-parameters.  The first parameter is the name of the pass that is to be used on
+template.  The template parameter is the name of the pass that is to be used on
 the command line to specify that the pass should be added to a program (for
-example, with opt or bugpoint).  The second argument is the
-name of the pass, which is to be used for the --help output of
+example, with opt or bugpoint).  The first argument is the
+name of the pass, which is to be used for the -help output of
 programs, as
 well as for debug output generated by the --debug-pass option.
 
 If you want your pass to be easily dumpable, you should 
 implement the virtual print method:
 
-
-
 
-
+
   The print method
-
+
 
-
+
 
 -  virtual void print(llvm::OStream &O, const Module *M) const;
+  virtual void print(std::ostream &O, const Module *M) const;
 
 
 The print method must be implemented by "analyses" in order to print
@@ -987,15 +1121,17 @@ depended on.
 
 
 
+
+
 
-
+
   Specifying interactions between passes
-
+
 
 
-
+
 
-One of the main responsibilities of the PassManager is the make sure
+
One of the main responsibilities of the PassManager is to make sure
 that passes interact with each other correctly.  Because PassManager
 tries to optimize the execution of passes it must
 know how the passes interact with each other and what dependencies exist between
@@ -1010,14 +1146,12 @@ specifies.  If a pass does not implement the getAnalysisUsage method, it defaults to not
 having any prerequisite passes, and invalidating all other passes.
 
-
-
 
-
+
   The getAnalysisUsage method
-
+
 
-
+
 
    virtual void getAnalysisUsage(AnalysisUsage &Info) const;
@@ -1033,11 +1167,14 @@ object:
 
 
 
-
-  The AnalysisUsage::addRequired<> and AnalysisUsage::addRequiredTransitive<> methods
-
-
-
+
+  
+    The AnalysisUsage::addRequired<>
+    and AnalysisUsage::addRequiredTransitive<> methods
+  
+
+
+
 
 If your pass requires a previous pass to be executed (an analysis for example),
 it can use one of these methods to arrange for it to be run before your pass.
@@ -1059,11 +1196,13 @@ pass is.
 
 
 
-
-  The AnalysisUsage::addPreserved<> method
-
+
+  
+    The AnalysisUsage::addPreserved<> method
+  
+
 
-
+
 
 One of the jobs of the PassManager is to optimize how and when analyses are run.
 In particular, it attempts to avoid recomputing data unless it needs to.  For
@@ -1094,22 +1233,13 @@ the fact that it hacks on the CFG.
 
 
 
-
-  Example implementations of getAnalysisUsage
-
+
+  
+    Example implementations of getAnalysisUsage
+  
+
 
-
-
--  // This is an example implementation from an analysis, which does not modify
-  // the program at all, yet has a prerequisite.
-  void PostDominanceFrontier::getAnalysisUsage(AnalysisUsage &AU) const {
-    AU.setPreservesAll();
-    AU.addRequired<PostDominatorTree>();
-  }
-
-
-and:
+
 
    // This example modifies the program, but does not modify the CFG
@@ -1122,11 +1252,14 @@ the fact that it hacks on the CFG.
 
 
 
-
-  The getAnalysis<> and getAnalysisToUpdate<> methods
-
+
+  
+    The getAnalysis<> and
+    getAnalysisIfAvailable<> methods
+  
+
 
-
+
 
 The Pass::getAnalysis<> method is automatically inherited by
 your class, providing you with access to the passes that you declared that you
@@ -1165,12 +1298,12 @@ before returning a reference to the desired pass.
 
 If your pass is capable of updating analyses if they exist (e.g.,
 BreakCriticalEdges, as described above), you can use the
-getAnalysisToUpdate method, which returns a pointer to the analysis if
-it is active.  For example:
+getAnalysisIfAvailable method, which returns a pointer to the analysis
+if it is active.  For example:
 
    ...
-  if (DominatorSet *DS = getAnalysisToUpdate<DominatorSet>()) {
+  if (DominatorSet *DS = getAnalysisIfAvailable<DominatorSet>()) {
     // A DominatorSet is active.  This code will update it.
   }
   ...
@@ -1178,15 +1311,17 @@ it is active.  For example:
 
 
 
+
+
 
-
+
   Implementing Analysis Groups
-
+
 
 
-
+
 
-Now that we understand the basics of how passes are defined, how the are
+
Now that we understand the basics of how passes are defined, how they are
 used, and how they are required from other passes, it's time to get a little bit
 fancier.  All of the pass relationships that we have seen so far are very
 simple: one pass depends on one other specific pass to be run before it can run.
@@ -1203,14 +1338,12 @@ between these two extremes for other implementations).  To cleanly support
 situations like this, the LLVM Pass Infrastructure supports the notion of
 Analysis Groups.
 
-
-
 
-
+
   Analysis Group Concepts
-
+
 
-
+
 
 An Analysis Group is a single simple interface that may be implemented by
 multiple different passes.  Analysis Groups can be given human readable names
@@ -1228,7 +1361,7 @@ between passes still apply.
 
 Although Pass Registration is optional for normal
 passes, all analysis group implementations must be registered, and must use the
-RegisterAnalysisGroup template to join the
+INITIALIZE_AG_PASS template to join the
 implementation pool.  Also, a default implementation of the interface
 must be registered with RegisterAnalysisGroup.
@@ -1257,15 +1390,17 @@ hypothetical example) instead.
 
 
 
-
+
   Using RegisterAnalysisGroup
-
+
 
-
+
 
 The RegisterAnalysisGroup template is used to register the analysis
-group itself as well as add pass implementations to the analysis group.  First,
-an analysis should be registered, with a human readable name provided for it.
+group itself, while the INITIALIZE_AG_PASS is used to add pass
+implementations to the analysis group.  First,
+an analysis group should be registered, with a human readable name
+provided for it.
 Unlike registration of passes, there is no command line argument to be specified
 for the Analysis Group Interface itself, because it is "abstract":
 
@@ -1278,49 +1413,53 @@ implementations of the interface by using the following code:
 
  namespace {
-  // Analysis Group implementations must be registered normally...
-  RegisterPass<FancyAA>
-  B("somefancyaa", "A more complex alias analysis implementation");
-
   // Declare that we implement the AliasAnalysis interface
-  RegisterAnalysisGroup<AliasAnalysis> C(B);
+  INITIALIZE_AG_PASS(FancyAA, AliasAnalysis, "somefancyaa",
+                     "A more complex alias analysis implementation",
+                     false, // Is CFG Only?
+                     true,  // Is Analysis?
+                     false, // Is default Analysis Group implementation?
+                    );
 }
 
 
-This just shows a class FancyAA that is registered normally, then
-uses the RegisterAnalysisGroup template to "join" the AliasAnalysis
+
This just shows a class FancyAA that 
+uses the INITIALIZE_AG_PASS macro both to register and
+to "join" the AliasAnalysis
 analysis group.  Every implementation of an analysis group should join using
-this template.  A single pass may join multiple different analysis groups with
-no problem.
+this macro.
 
  namespace {
-  // Analysis Group implementations must be registered normally...
-  RegisterPass<BasicAliasAnalysis>
-  D("basicaa", "Basic Alias Analysis (default AA impl)");
-
   // Declare that we implement the AliasAnalysis interface
-  RegisterAnalysisGroup<AliasAnalysis, true> E(D);
+  INITIALIZE_AG_PASS(BasicAA, AliasAnalysis, "basicaa",
+                     "Basic Alias Analysis (default AA impl)",
+                     false, // Is CFG Only?
+                     true,  // Is Analysis?
+                     true, // Is default Analysis Group implementation?
+                    );
 }
 
 
-Here we show how the default implementation is specified (using the extra
-argument to the RegisterAnalysisGroup template).  There must be exactly
+
Here we show how the default implementation is specified (using the final
+argument to the INITIALIZE_AG_PASS template).  There must be exactly
 one default implementation available at all times for an Analysis Group to be
-used.  Here we declare that the BasicAliasAnalysis
+used.  Only default implementation can derive from ImmutablePass. 
+Here we declare that the
+ BasicAliasAnalysis
 pass is the default implementation for the interface.
 
 
 
+
+
 
-
+
   Pass Statistics
-
+
 
 
-
+
 The Statistic
 class is designed to be an easy way to expose various success
@@ -1332,12 +1471,12 @@ line. See the St
 
 
 
-

+
   What PassManager does
-
+
 
 
-
+
 
 The PassManager
@@ -1363,7 +1502,7 @@ results as soon as they are no longer needed.
 
Pipeline the execution of passes on the program - The
 PassManager attempts to get better cache and memory usage behavior out
 of a series of passes by pipelining the passes together.  This means that, given
-a series of consequtive FunctionPass's, it
+a series of consecutive FunctionPass's, it
 will execute all of the FunctionPass's on
 the first function, then all of the FunctionPasses on the second function,
@@ -1374,7 +1513,8 @@ the LLVM program representation for a single function at a time, instead of
 traversing the entire program.  It reduces the memory consumption of compiler,
 because, for example, only one DominatorSet
-needs to be calculated at a time.  This also makes it possible some interesting enhancements in the future.

Writing an LLVM Pass -

Introduction - What is a pass? -

Quick Start - Writing hello world -

Setting up the build environment -

Basic code required -

Running a pass with opt -

Pass classes and requirements -

The ImmutablePass class -

The ModulePass class -

The runOnModule method -

The CallGraphSCCPass class -

+ + The doInitialization(CallGraph &) method + +

The runOnSCC method -

+ + The doFinalization(CallGraph &) method + +

The FunctionPass class -

+ + The doInitialization(Module &) method + +

The runOnFunction method -

+ + The doFinalization(Module &) method + +

The LoopPass class -

+ + The doInitialization(Loop *,LPPassManager &) method + +

The runOnLoop method -

The doFinalization() method -

+ The RegionPass class +

+ + The doInitialization(Region *, RGPassManager &) method + +

+ The runOnRegion method +

+ The doFinalization() method +

The BasicBlockPass class -

+ + The doInitialization(Function &) method + +

The runOnBasicBlock method -

+ + The doFinalization(Function &) method + +

The MachineFunctionPass class -

+ + The runOnMachineFunction(MachineFunction &MF) method + +

Pass registration -

The print method -

Specifying interactions between passes -

The getAnalysisUsage method -

+ + The AnalysisUsage::addRequired<> + and AnalysisUsage::addRequiredTransitive<> methods + +

+ + The AnalysisUsage::addPreserved<> method + +

+ + Example implementations of getAnalysisUsage + +

+ + The getAnalysis<> and + getAnalysisIfAvailable<> methods + +

Implementing Analysis Groups -

Analysis Group Concepts -

Using RegisterAnalysisGroup -

Pass Statistics -

What PassManager does -

The releaseMemory method -

Registering dynamically loaded passes -

Using existing registries -

Creating new registries -

Using GDB with dynamically loaded passes -

Setting a breakpoint in your pass -

Miscellaneous Problems -

Future extensions planned -

Multithreaded LLVM -

Running a pass with `opt` -

The `ImmutablePass` class -

The `ModulePass` class -

The `runOnModule` method -

The `CallGraphSCCPass` class -

+ + The `doInitialization(CallGraph &)` method + +

The `runOnSCC` method -

+ + The `doFinalization(CallGraph &)` method + +

The `FunctionPass` class -

+ + The `doInitialization(Module &)` method + +

The `runOnFunction` method -

+ + The `doFinalization(Module &)` method + +

The `LoopPass` class -

+ + The `doInitialization(Loop *,LPPassManager &)` method + +

The `runOnLoop` method -

The `doFinalization()` method -

+ The `RegionPass` class +

+ + The `doInitialization(Region *, RGPassManager &)` method + +

+ The `runOnRegion` method +

+ The `doFinalization()` method +

The `BasicBlockPass` class -

+ + The `doInitialization(Function &)` method + +

The `runOnBasicBlock` method -

+ + The `doFinalization(Function &)` method + +

The `MachineFunctionPass` class -

+ + The `runOnMachineFunction(MachineFunction &MF)` method + +

The `print` method -

The `getAnalysisUsage` method -

+ + The `AnalysisUsage::addRequired<>` + and `AnalysisUsage::addRequiredTransitive<>` methods + +

+ + The `AnalysisUsage::addPreserved<>` method + +

+ + Example implementations of `getAnalysisUsage` + +

+ + The `getAnalysis<>` and + `getAnalysisIfAvailable<>` methods + +

Using `RegisterAnalysisGroup` -

The `releaseMemory` method -