This document is meant to highlight some of the important classes and interfaces available in the LLVM source-base. This manual is not @@ -240,24 +242,22 @@ href="/doxygen/InstVisitor_8h-source.html">InstVisitor template.

General Information -

+ -

This section contains general information that is useful if you are working in the LLVM source-base, but that isn't specific to any particular API.

- -

The C++ Standard Template Library -

+ -

LLVM makes heavy use of the C++ Standard Template Library (STL), perhaps much more than you are used to, or have seen before. Because of @@ -303,11 +303,11 @@ to write maintainable code more than where to put your curly braces.

Other useful references -

+ -

Using @@ -316,26 +316,26 @@ static and shared libraries across platforms

+ -

Important and useful LLVM APIs -

+ -

Here we highlight some LLVM APIs that are generally useful and good to know about when writing transformations.

- -

The `isa<>`, `cast<>` and `dyn_cast<>` templates -

+ -

The LLVM source-base makes extensive use of a custom form of RTTI. These templates have many similarities to the C++ dynamic_cast<> @@ -440,12 +440,12 @@ are lots of examples in the LLVM source base.

Passing strings (the `StringRef` and `Twine` classes) -

+ -

Although LLVM generally does not do much string manipulation, we do have several important APIs which take strings. Two important examples are the @@ -459,14 +459,12 @@ clients to perform a heap allocation which is usually unnecessary. Instead, many LLVM APIs use a StringRef or a const Twine& for passing strings efficiently.

- -

The `StringRef` class -

+ -

The StringRef data type represents a reference to a constant string (a character array and a length) and supports the common operations available @@ -502,11 +500,11 @@ small and pervasive enough in LLVM that it should always be passed by value.

The `Twine` class -

+ -

The Twine class is an efficient way for APIs to accept concatenated strings. For example, a common LLVM paradigm is to name one instruction based on @@ -537,13 +535,14 @@ accept concatenated strings.

The `DEBUG()` macro and `-debug` option -

+ -

Often when working on your pass you will put a bunch of debugging printouts and other code into your pass. After you get it working, you want to remove @@ -589,15 +588,13 @@ enable or disable it directly in gdb. Just use "set DebugFlag=0" or program hasn't been started yet, you can always just run it with -debug.

- -

Fine grained debug info with `DEBUG_TYPE` and the `-debug-only` option -

+ -

Sometimes you may find yourself in a situation where enabling -debug just turns on too much information (such as when working on the code @@ -665,13 +662,15 @@ DEBUG_WITH_TYPE("", errs() << "No debug type (2)\n");

+ -

The `Statistic` class & `-stats` option -

+ -

The "llvm/ADT/Statistic.h" file @@ -766,11 +765,11 @@ maintainable and useful.

Viewing graphs while debugging code -

+ -

Several of the important data structures in LLVM are graphs: for example CFGs made out of LLVM BasicBlocks, CFGs made out of @@ -814,13 +813,15 @@ attributes, then you can call DAG.clearGraphAttrs().

+ -

Picking the Right Data Structure for a Task -

+ -

LLVM has a plethora of data structures in the llvm/ADT/ directory, and we commonly use STL data structures. This section describes the trade-offs @@ -876,35 +877,47 @@ elements (but could contain many), for example, it's much better to use . Doing so avoids (relatively) expensive malloc/free calls, which dwarf the cost of adding the elements to the container.

- -

Sequential Containers (std::vector, std::list, etc) -

+ -

There are a variety of sequential containers available for you, based on your needs. Pick the first in this section that will do what you want. + + +

+ llvm/ADT/ArrayRef.h +

+ +

The llvm::ArrayRef class is the preferred class to use in an interface that + accepts a sequential list of elements in memory and just reads from them. By + taking an ArrayRef, the API can be passed a fixed size array, an std::vector, + an llvm::SmallVector and anything else that is contiguous in memory. +

+ + -

Fixed Size Arrays -

+ -

Fixed size arrays are very simple and very fast. They are good if you know exactly how many elements you have, or you have a (low) upper bound on how many you have.

Heap Allocated Arrays -

+ -

Heap allocated arrays (new[] + delete[]) are also simple. They are good if the number of elements is variable, if you know how many elements you will need before the array is allocated, and if the array is usually large (if not, @@ -916,11 +929,11 @@ construct those elements actually used).

"llvm/ADT/SmallVector.h" -

+ -

SmallVector<Type, N> is a simple class that looks and smells just like vector<Type>: it supports efficient iteration, lays out elements in memory order (so you can @@ -945,11 +958,11 @@ SmallVectors are most useful when on the stack.

<vector> -

+ -

std::vector is well loved and respected. It is useful when SmallVector isn't: when the size of the vector is often large (thus the small optimization will @@ -987,11 +1000,11 @@ the loop.

<deque> -

+ -

std::deque is, in some senses, a generalized version of std::vector. Like std::vector, it provides constant time random access and other similar properties, but it also provides efficient access to the front of the list. It @@ -1003,11 +1016,11 @@ something cheaper.

<list> -

+ -

std::list is an extremely inefficient class that is rarely useful. It performs a heap allocation for every element inserted into it, thus having an extremely high constant factor, particularly for small data types. std::list @@ -1021,11 +1034,11 @@ not invalidate iterator or pointers to other elements in the list.

llvm/ADT/ilist.h -

+ -

ilist<T> implements an 'intrusive' doubly-linked list. It is intrusive, because it requires the element to store and provide access to the prev/next pointers for the list.

@@ -1051,22 +1064,22 @@ Related classes of interest are explained in the following subsections:

ilist_traits -

+ -

ilist_traits<T> is ilist<T>'s customization mechanism. iplist<T> (and consequently ilist<T>) publicly derive from this traits class.

iplist -

+ -

iplist<T> is ilist<T>'s base and as such supports a slightly narrower interface. Notably, inserters from T& are absent.

@@ -1076,11 +1089,11 @@ used for a wide variety of customizations.

llvm/ADT/ilist_node.h -

+ -

ilist_node<T> implements a the forward and backward links that are expected by the ilist<T> (and analogous containers) in the default manner.

@@ -1091,11 +1104,11 @@ in the default manner.

Sentinels -

+ -

ilists have another specialty that must be considered. To be a good citizen in the C++ ecosystem, it needs to support the standard container operations, such as begin and end iterators, etc. Also, the @@ -1129,11 +1142,11 @@ field in the ghostly sentinel which can be legally accessed.

Other Sequential Container options -

+ -

Other STL containers are available, such as std::string.

There are also various STL adapter classes such as std::queue, @@ -1142,27 +1155,25 @@ underlying container but don't affect the cost of the container itself.

Set-Like Containers (std::set, SmallSet, SetVector, etc) -

+ -

Set-like containers are useful when you need to canonicalize multiple values into a single representation. There are several different choices for how to do this, providing various trade-offs.

- - -

A sorted 'vector' -

+ -

If you intend to insert a lot of elements, then do a lot of queries, a great approach is to use a vector (or other sequential container) with @@ -1180,11 +1191,11 @@ efficiently queried with a standard binary or radix search.

"llvm/ADT/SmallSet.h" -

+ -

If you have a set-like data structure that is usually small and whose elements are reasonably small, a SmallSet<Type, N> is a good choice. This set @@ -1203,11 +1214,11 @@ and erasing, but does not support iteration.

"llvm/ADT/SmallPtrSet.h" -

+ -

SmallPtrSet has all the advantages of SmallSet (and a SmallSet of pointers is transparently implemented with a SmallPtrSet), but also supports iterators. If @@ -1223,11 +1234,11 @@ visited in sorted order.

"llvm/ADT/DenseSet.h" -

+ -

DenseSet is a simple quadratically probed hash table. It excels at supporting @@ -1242,11 +1253,11 @@ href="#dss_densemap">DenseMap has.

"llvm/ADT/FoldingSet.h" -

+ -

FoldingSet is an aggregate class that is really good at uniquing @@ -1279,11 +1290,11 @@ elements.

<set> -

+ -

std::set is a reasonable all-around set class, which is decent at many things but great at nothing. std::set allocates memory for each element @@ -1304,11 +1315,11 @@ std::set is almost never a good choice.

"llvm/ADT/SetVector.h" -

+ -

LLVM's SetVector<Type> is an adapter class that combines your choice of a set-like container along with a Sequential Container. The important property @@ -1344,11 +1355,11 @@ heap traffic.

"llvm/ADT/UniqueVector.h" -

+ -

UniqueVector is similar to SetVector, but it @@ -1364,11 +1375,11 @@ factors, and produces a lot of malloc traffic. It should be avoided.

Other Set-Like Container Options -

+ -

The STL provides several other options, such as std::multiset and the various @@ -1384,22 +1395,23 @@ better.

+ -

Map-Like Containers (std::map, DenseMap, etc) -

+ -

Map-like containers are useful when you want to associate data to a key. As usual, there are a lot of different ways to do this. :) -

A sorted 'vector' -

+ -

If your usage pattern follows a strict insert-then-query approach, you can @@ -1412,11 +1424,11 @@ vectors for sets.

"llvm/ADT/StringMap.h" -

+ -

Strings are commonly used as keys in maps, and they are difficult to support @@ -1446,11 +1458,11 @@ copies a string if a value is inserted into the table.

"llvm/ADT/IndexedMap.h" -

+ -

IndexedMap is a specialized container for mapping small dense integers (or values that can be mapped to small dense integers) to some other type. It is @@ -1466,11 +1478,11 @@ virtual register ID).

"llvm/ADT/DenseMap.h" -

+ -

DenseMap is a simple quadratically probed hash table. It excels at supporting @@ -1492,11 +1504,11 @@ inserted into the map) that it needs internally.

"llvm/ADT/ValueMap.h" -

+ -

ValueMap is a wrapper around a DenseMap mapping @@ -1509,11 +1521,11 @@ a Config parameter to the ValueMap template.

"llvm/ADT/IntervalMap.h" -

+ -

IntervalMap is a compact map for small keys and values. It maps key intervals instead of single keys, and it will automatically coalesce adjacent @@ -1526,11 +1538,11 @@ as STL iterators. The heavyweight iterators allow a smaller data structure.

<map> -

+ -

std::map has similar characteristics to std::set: it uses @@ -1546,11 +1558,31 @@ another element takes place).

- Other Map-Like Container Options +

+ "llvm/ADT/IntEqClasses.h" +

+ +

IntEqClasses provides a compact representation of equivalence classes of +small integers. Initially, each integer in the range 0..n-1 has its own +equivalence class. Classes can be joined by passing two class representatives to +the join(a, b) method. Two integers are in the same class when findLeader() +returns the same representative.

+ +

Once all equivalence classes are formed, the map can be compressed so each +integer 0..n-1 maps to an equivalence class number in the range 0..m-1, where m +is the total number of equivalence classes. The map must be uncompressed before +it can be edited again.

+ +

+ Other Map-Like Container Options +

+ +

The STL provides several other options, such as std::multimap and the various @@ -1564,12 +1596,14 @@ always better.

+ -

String-like containers -

+ -

TODO: const char* vs stringref vs smallstring vs std::string. Describe twine, @@ -1579,11 +1613,11 @@ xref to #string_apis.

Bit storage containers (BitVector, SparseBitVector) -

+ -

Unlike the other containers, there are only two bit storage containers, and choosing when to use each is relatively straightforward.

@@ -1593,14 +1627,13 @@ implementation in many common compilers (e.g. commonly available versions of GCC) is extremely inefficient and 2) the C++ standards committee is likely to deprecate this container and/or change it significantly somehow. In any case, please don't use it.

BitVector -

+ -

The BitVector container provides a dynamic size set of bits for manipulation. It supports individual bit setting/testing, as well as set operations. The set operations take time O(size of bitvector), but operations are performed one word @@ -1611,11 +1644,11 @@ the number of set bits to be high (IE a dense set).

SmallBitVector -

+ -

The SmallBitVector container provides the same interface as BitVector, but it is optimized for the case where only a small number of bits, less than 25 or so, are needed. It also transparently supports larger bit counts, but @@ -1630,11 +1663,11 @@ and its operator[] does not provide an assignable lvalue.

SparseBitVector -

+ -

The SparseBitVector container is much like BitVector, with one major difference: Only the bits that are set, are stored. This makes the SparseBitVector much more space efficient than BitVector when the set is sparse, @@ -1644,13 +1677,17 @@ universe). The downside to the SparseBitVector is that setting and testing of r

+ +

+ -

Helpful Hints for Common Operations -

+ -

This section describes how to perform some very simple transformations of LLVM code. This is meant to give examples of common idioms used, showing the @@ -1659,15 +1696,13 @@ you should also read about the main classes that you will be working with. The Core LLVM Class Hierarchy Reference contains details and descriptions of the main classes that you should know about.

- -

Basic Inspection and Traversal Routines -

+ -

The LLVM compiler infrastructure have many different data structures that may be traversed. Following the example of the C++ standard template library, the @@ -1684,16 +1719,14 @@ on them, and it is easier to remember how to iterate. First we show a few common examples of the data structures that need to be traversed. Other data structures are traversed in very similar ways.

- -

Iterating over the `BasicBlock`s in a `Function` -

+ -

It's quite common to have a Function instance that you'd like to transform in some way; in particular, you'd like to manipulate its @@ -1722,13 +1755,13 @@ exactly equivalent to (*i).size() just like you'd expect.

Iterating over the `Instruction`s in a `BasicBlock` -

+ -

Just like when dealing with BasicBlocks in Functions, it's easy to iterate over the individual instructions that make up @@ -1753,13 +1786,13 @@ basic block itself: errs() << *blk << "\n";.

Iterating over the `Instruction`s in a `Function` -

+ -

If you're finding that you commonly iterate over a Function's BasicBlocks and then that BasicBlock's Instructions, @@ -1799,12 +1832,12 @@ for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)

Turning an iterator into a class pointer (and vice-versa) -

+ -

Sometimes, it'll be useful to grab a reference (or pointer) to a class instance when all you've got at hand is an iterator. Well, extracting @@ -1876,12 +1909,12 @@ and operator* changed to return a pointer instead of a reference.

Finding call sites: a slightly more complex example -

+ -

Say that you're writing a FunctionPass and would like to count all the locations in the entire module (that is, across every Function) where a @@ -1938,11 +1971,11 @@ class OurFunctionPass : public FunctionPass {

Treating calls and invokes the same way -

+ -

You may have noticed that the previous example was a bit oversimplified in that it did not deal with call sites generated by 'invoke' instructions. In @@ -1965,11 +1998,11 @@ If you look at its definition, it has only a single pointer member.

Iterating over def-use & use-def chains -

+ -

Frequently, we might have an instance of the Value Class and we want to @@ -2026,12 +2059,12 @@ calling use/op_begin() on const Value*s or

Iterating over predecessors & successors of blocks -

+ -

Iterating over the predecessors and successors of a block is quite easy with the routines defined in "llvm/Support/CFG.h". Just use code like @@ -2054,13 +2087,14 @@ succ_iterator/succ_begin/succ_end.

Making simple changes -

+ -

There are some primitive transformation operations present in the LLVM infrastructure that are worth knowing about. When performing @@ -2068,15 +2102,13 @@ transformations, it's fairly common to manipulate the contents of basic blocks. This section describes some of the common methods for doing so and gives example code.

- -

Creating and inserting new `Instruction`s -

+ -

Instantiating Instructions

@@ -2212,18 +2244,15 @@ Instruction* newInst = new Instruction(..., pi);

Deleting `Instruction`s -

+ -

Deleting an instruction from an existing sequence of instructions that form a -BasicBlock is very straight-forward. First, -you must have a pointer to the instruction that you wish to delete. Second, you -need to obtain the pointer to that instruction's basic block. You use the -pointer to the basic block to get its list of instructions and then use the -erase function to remove your instruction. For example:

+BasicBlock is very straight-forward: just +call the instruction's eraseFromParent() method. For example:

@@ -2232,15 +2261,19 @@ I->eraseFromParent();

This unlinks the instruction from its containing basic block and deletes +it. If you'd just like to unlink the instruction from its containing basic +block but not delete it, you can use the removeFromParent() method.

Replacing an `Instruction` with another `Value` -

+ -

Replacing individual instructions

@@ -2248,7 +2281,7 @@ I->eraseFromParent(); permits use of two very useful replace functions: ReplaceInstWithValue and ReplaceInstWithInst.

Deleting `Instruction`s

ReplaceInstWithValue @@ -2301,11 +2334,11 @@ ReplaceInstWithValue, ReplaceInstWithInst -->

Deleting `GlobalVariable`s -

+ -

Deleting a global variable from a module is just as easy as deleting an Instruction. First, you must have a pointer to the global variable that you wish @@ -2322,12 +2355,14 @@ GV->eraseFromParent();

+ -

How to Create Types -

+ -

In generating IR, you may need some complex types. If you know these types statically, you can use TypeBuilder<...>::get(), defined @@ -2362,13 +2397,15 @@ comment for more details.

+ -

Threads and LLVM -

+ -

This section describes the interaction of the LLVM APIs with multithreading, both on the part of client applications, and in the JIT, in the hosted @@ -2391,14 +2428,13 @@ compiler, consider compiling LLVM and LLVM-GCC in single-threaded mode, and using the resultant compiler to build a copy of LLVM with multithreading support.

Entering and Exiting Multithreaded Mode -

+ -

In order to properly protect its internal data structures while avoiding @@ -2431,11 +2467,11 @@ result in concurrent LLVM API calls.

Ending Execution with `llvm_shutdown()` -

+ -

When you are done using the LLVM APIs, you should call llvm_shutdown() to deallocate memory used for internal structures. This will also invoke @@ -2451,11 +2487,11 @@ destructor.

Lazy Initialization with `ManagedStatic` -

+ -

ManagedStatic is a utility class in LLVM used to implement static initialization of static resources, such as the global type tables. Before the @@ -2480,11 +2516,11 @@ and only if you know what you're doing!

Achieving Isolation with `LLVMContext` -

+ -

LLVMContext is an opaque class in the LLVM API which clients can use to operate multiple, isolated instances of LLVM concurrently within the same @@ -2524,11 +2560,11 @@ isolation is not a concern.

Threads and the JIT -

+ -

LLVM's "eager" JIT compiler is safe to use in threaded programs. Multiple threads can call ExecutionEngine::getPointerToFunction() or @@ -2551,26 +2587,27 @@ access, but we suggest using only the eager JIT in threaded programs.

+ -

Advanced Topics -

+ -

This section describes some of the advanced or obscure API's that most clients do not need to be aware of. These API's tend manage the inner workings of the LLVM system, and only need to be accessed in unusual circumstances.

LLVM Type Resolution -

+ -

The LLVM type system has a very simple goal: allow clients to compare types for @@ -2599,14 +2636,12 @@ Third, a concrete type is a type that is not an abstract type (e.g. "{ i32, float }").

- -

Basic Recursive Type Construction -

+ -

Because the most common question is "how do I build a recursive type with LLVM", @@ -2658,11 +2693,11 @@ href="#PATypeHolder">PATypeHolder class.

The `refineAbstractTypeTo` method -

+ -

The refineAbstractTypeTo method starts the type unification process. While this method is actually a member of the DerivedType class, it is most @@ -2688,11 +2723,11 @@ complex datastructures.

The PATypeHolder Class -

+ -

PATypeHolder is a form of a "smart pointer" for Type objects. When VMCore happily goes about nuking types that become isomorphic to existing types, it @@ -2710,11 +2745,11 @@ Type is maintained by PATypeHolder objects.

The AbstractTypeUser Class -

+ -

Some data structures need more to perform more complex updates when types get @@ -2728,14 +2763,15 @@ objects) can never be refined.

The `ValueSymbolTable` and `TypeSymbolTable` classes -

+ -

The ValueSymbolTable class provides a symbol table that the Function and @@ -2766,11 +2802,11 @@ insert entries into the symbol table.

The `User` and owned `Use` classes' memory layout -

+ -

The User class provides a basis for expressing the ownership of User towards other @@ -2779,18 +2815,19 @@ Use helper class is employed to do the bookkeeping and to facilitate -

- Interaction and relationship between User and Use objects -

+
+ + Interaction and relationship between User and Use objects + +
-
+

A subclass of User can choose between incorporating its Use objects or refer to them out-of-line by means of a pointer. A mixed variant (some Uses inline others hung off) is impractical and breaks the invariant that the Use objects belonging to the same User form a contiguous array.
-

We have 2 different layouts in the User (sub)classes: @@ -2839,17 +2876,18 @@ enforce the following memory layouts:
(In the above figures 'P' stands for the Use** that is stored in each Use object in the member Use::Prev) +
+ -
+
The waymarking algorithm -
+ -
+

Since the Use objects are deprived of the direct (back)pointer to their User objects, there must be a fast and exact method to recover it. This is accomplished by the following scheme:
-
A bit-encoding in the 2 LSBits (least significant bits) of the Use::Prev allows to find the start of the User object: @@ -2880,15 +2918,16 @@ Only the significant number of bits need to be stored between the stops, so that the worst case is 20 memory accesses when there are 1000 Use objects associated with a User.
+
+ -
+
Reference implementation -
+ -
+

The following literate Haskell fragment demonstrates the concept:
-

@@ -2970,10 +3009,14 @@ And here is the result of <deepCheck identityProp>:
OK, passed 500 tests.
+
+ -
+
Tagging considerations -
+ + +

To maintain the invariant that the 2 LSBits of each Use** in Use @@ -2989,13 +3032,17 @@ the LSBit set. (Portability is relying on the fact that all known compilers plac
- -
- The Core LLVM Class Hierarchy Reference
+ +
+ + +
+ The Core LLVM Class Hierarchy Reference +
-
+

#include "llvm/Type.h"
doxygen info: Type Class
@@ -3004,14 +3051,12 @@ being inspected or transformed. The core LLVM classes are defined in header files in the include/llvm/ directory, and implemented in the lib/VMCore directory.
-
- -
+
The Type class and Derived Types -
+ -
+

Type is a superclass of all type classes. Every Value has a Type. Type cannot be instantiated directly but only @@ -3026,14 +3071,13 @@ the lib/VMCore directory.
be performed with address equality of the Type Instance. That is, given two Type* values, the types are identical if the pointers are identical.
-
-
+
Important Public Methods -
+ -
+

bool isIntegerTy() const: Returns true for any integer type.
@@ -3051,10 +3095,10 @@ the lib/VMCore directory.

-
+
Important Derived Types -
-
+ +

IntegerType

Subclass of DerivedType that represents integer types of any bit width. @@ -3116,14 +3160,14 @@ the lib/VMCore directory.

- +
-
+
The Module class -
+ -
+

#include "llvm/Module.h"
doxygen info: @@ -3138,14 +3182,12 @@ href="#GlobalVariable">GlobalVariables, and a SymbolTable. Additionally, it contains a few helpful member functions that try to make common operations easy.
-
- -
+
Important Public Members of the Module class -
+ -
+

Module::Module(std::string name = "")
@@ -3244,13 +3286,14 @@ provide a name for it (probably based on the name of the translation unit).

+
-
+
The Value class -
+ -
+

#include "llvm/Value.h"
@@ -3301,14 +3344,12 @@ the class that represents this value. Although this may take some getting used to, it simplifies the representation and makes it easier to manipulate.
-
- -
+
Important Public Members of the Value class -
+ -
+

Value::use_iterator - Typedef for iterator over the @@ -3355,12 +3396,14 @@ Inst->replaceAllUsesWith(ConstVal);
+
+ -
+
The User class -
+ -
+

#include "llvm/User.h"
@@ -3379,14 +3422,12 @@ Single Assignment (SSA) form, there can only be one definition referred to, allowing this direct connection. This connection provides the use-def information in LLVM.
-
- -
+
Important Public Members of the User class -
+ -
+

The User class exposes the operand list in two ways: through an index access interface and through an iterator based interface.
@@ -3409,12 +3450,14 @@ the operands of a User.

+
+ -
+
The Instruction class -
+ -
+

#include "llvm/Instruction.h"
@@ -3445,14 +3488,13 @@ href="#CmpInst">CmpInst). Unfortunately, the use of macros in this file confuses doxygen, so these enum values don't show up correctly in the doxygen output.
-
- -
- Important Subclasses of the Instruction - class -
-
+
+ + Important Subclasses of the Instruction class + +
+

BinaryOperator
This subclasses represents all two operand instructions whose operands @@ -3471,12 +3513,13 @@ this file confuses doxygen, so these enum values don't show up correctly in the
-
- Important Public Members of the Instruction - class -
+
+ + Important Public Members of the Instruction class + +
-
+

BasicBlock *getParent() @@ -3496,12 +3539,14 @@ and it has no name

+
+ -
+
The Constant class and subclasses -
+ -
+

Constant represents a base class for different types of constants. It is subclassed by ConstantInt, ConstantArray, etc. for representing @@ -3509,11 +3554,9 @@ the various types of Constants. GlobalValue is also a subclass, which represents the address of a global variable or function.
-
- -
Important Subclasses of Constant
-
+
Important Subclasses of Constant
+

ConstantInt : This subclass of Constant represents an integer constant of any width. @@ -3561,13 +3604,14 @@ a subclass, which represents the address of a global variable or function.

+
-
+
The GlobalValue class -
+ -
+

#include "llvm/GlobalValue.h"
@@ -3607,15 +3651,14 @@ dereference the pointer with GetElementPtrInst first, then its elements can be accessed. This is explained in the LLVM Language Reference Manual.
-
- -
- Important Public Members of the GlobalValue - class -
+
+ + Important Public Members of the GlobalValue class + +
-
+

bool hasInternalLinkage() const
@@ -3631,12 +3674,14 @@ GlobalValue is currently embedded into.

+
+ -
+
The Function class -
+ -
+

#include "llvm/Function.h"
doxygen @@ -3683,15 +3728,15 @@ href="#Argument">Arguments in the function body.

Note that Function is a GlobalValue and therefore also a Constant. The value of the function is its address (after linking) which is guaranteed to be constant.
-
-
- Important Public Members of the Function - class -
+
+ + Important Public Members of the Function class + +
-
+

Function(const FunctionType @@ -3769,12 +3814,14 @@ iterator
+
+ - + The GlobalVariable class - + - + #include "llvm/GlobalVariable.h" @@ -3796,15 +3843,15 @@ variables may have an initial value (which must be a Constant), and if they have an initializer, they may be marked as "constant" themselves (indicating that their contents never change at runtime). - - - Important Public Members of the - GlobalVariable class - + + + Important Public Members of the GlobalVariable class + + - + GlobalVariable(const Type *Ty, bool @@ -3842,13 +3889,14 @@ never change at runtime). + - + The BasicBlock class - + - + #include "llvm/BasicBlock.h" @@ -3873,15 +3921,14 @@ href="#Value">Values, because they are referenced by instructions like branches and can go in the switch tables. BasicBlocks have type label. - - - - Important Public Members of the BasicBlock - class - + + + Important Public Members of the BasicBlock class + + - + BasicBlock(const std::string &Name = "", + - + The Argument class - + - + This subclass of Value defines the interface for incoming formal arguments to a function. A Function maintains a list of its formal @@ -3947,6 +3995,8 @@ arguments. An argument has a pointer to the parent Function. + + @@ -3957,8 +4007,8 @@ arguments. An argument has a pointer to the parent Function. Dinakar Dhurjati and Chris Lattner - The LLVM Compiler Infrastructure - Last modified: $Date: 2011-02-17 03:19:22 +0100 (Thu, 17 Feb 2011) $ + The LLVM Compiler Infrastructure + Last modified: $Date: 2011-04-23 02:30:22 +0200 (Sat, 23 Apr 2011) $ -- cgit v1.1

LLVM Programmer's Manual -

Introduction -

General Information -

The C++ Standard Template Library -

Other useful references -

Important and useful LLVM APIs -

The isa<>, cast<> and dyn_cast<> templates -

Passing strings (the StringRef and Twine classes) -

The StringRef class -

The Twine class -

The DEBUG() macro and -debug option -

Fine grained debug info with DEBUG_TYPE and the -debug-only option -

The Statistic class & -stats option -

Viewing graphs while debugging code -

Picking the Right Data Structure for a Task -

Sequential Containers (std::vector, std::list, etc) -

+ llvm/ADT/ArrayRef.h +

Fixed Size Arrays -

Heap Allocated Arrays -

"llvm/ADT/SmallVector.h" -

<vector> -

<deque> -

<list> -

llvm/ADT/ilist.h -

ilist_traits -

iplist -

llvm/ADT/ilist_node.h -

Sentinels -

Other Sequential Container options -

Set-Like Containers (std::set, SmallSet, SetVector, etc) -

A sorted 'vector' -

"llvm/ADT/SmallSet.h" -

"llvm/ADT/SmallPtrSet.h" -

"llvm/ADT/DenseSet.h" -

"llvm/ADT/FoldingSet.h" -

<set> -

"llvm/ADT/SetVector.h" -

"llvm/ADT/UniqueVector.h" -

Other Set-Like Container Options -

Map-Like Containers (std::map, DenseMap, etc) -

A sorted 'vector' -

"llvm/ADT/StringMap.h" -

"llvm/ADT/IndexedMap.h" -

"llvm/ADT/DenseMap.h" -

"llvm/ADT/ValueMap.h" -

"llvm/ADT/IntervalMap.h" -

<map> -

+ "llvm/ADT/IntEqClasses.h" +

+ Other Map-Like Container Options +

String-like containers -

Bit storage containers (BitVector, SparseBitVector) -

BitVector -

SmallBitVector -

SparseBitVector -

Helpful Hints for Common Operations -

Basic Inspection and Traversal Routines -

Iterating over the BasicBlocks in a Function -

Iterating over the Instructions in a BasicBlock -

Iterating over the Instructions in a Function -

Turning an iterator into a class pointer (and vice-versa) -

Finding call sites: a slightly more complex example -

Treating calls and invokes the same way -

Iterating over def-use & use-def chains -

Iterating over predecessors & successors of blocks -

Making simple changes -

Creating and inserting new Instructions -

Deleting Instructions -

Replacing an Instruction with another Value -

Deleting Instructions

Deleting Instructions

Deleting GlobalVariables -

How to Create Types -

Threads and LLVM -

Entering and Exiting Multithreaded Mode -

Ending Execution with llvm_shutdown() -

Lazy Initialization with ManagedStatic -

Achieving Isolation with LLVMContext -

Threads and the JIT -

Advanced Topics -

LLVM Type Resolution -

The `isa<>`, `cast<>` and `dyn_cast<>` templates -

Passing strings (the `StringRef` and `Twine` classes) -

The `StringRef` class -

The `Twine` class -

The `DEBUG()` macro and `-debug` option -

Fine grained debug info with `DEBUG_TYPE` and the `-debug-only` option -

The `Statistic` class & `-stats` option -

Iterating over the `BasicBlock`s in a `Function` -

Iterating over the `Instruction`s in a `BasicBlock` -

Iterating over the `Instruction`s in a `Function` -

Creating and inserting new `Instruction`s -

Deleting `Instruction`s -

Replacing an `Instruction` with another `Value` -

Deleting `Instruction`s

Deleting `Instruction`s

Deleting `GlobalVariable`s -

Ending Execution with `llvm_shutdown()` -

Lazy Initialization with `ManagedStatic` -

Achieving Isolation with `LLVMContext` -

The `refineAbstractTypeTo` method -

The `ValueSymbolTable` and `TypeSymbolTable` classes -

The `User` and owned `Use` classes' memory layout -

+ + Interaction and relationship between `User` and `Use` objects + +

The `Type` class and Derived Types -

The `Module` class -

Important Public Members of the `Module` class -

The `Value` class -

Important Public Members of the `Value` class -

The `User` class -

Important Public Members of the `User` class -

The `Instruction` class -

+ + Important Subclasses of the `Instruction` class + +

+ + Important Public Members of the `Instruction` class + +

The `Constant` class and subclasses -

The `GlobalValue` class -

+ + Important Public Members of the `GlobalValue` class + +

The `Function` class -

+ + Important Public Members of the `Function` class + +

The `GlobalVariable` class -

+ + Important Public Members of the `GlobalVariable` class + +

The `BasicBlock` class -

+ + Important Public Members of the `BasicBlock` class + +

The `Argument` class -