From 263a98e4654f9fa6c6078446e21a958a33071d83 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Fri, 16 Feb 2007 04:37:31 +0000 Subject: [PATCH] update symtab section to reflect recent changes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@34340 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/ProgrammersManual.html | 165 +++++------------------------------- 1 file changed, 19 insertions(+), 146 deletions(-) diff --git a/docs/ProgrammersManual.html b/docs/ProgrammersManual.html index aa1fe402ff9..df8f4abf470 100644 --- a/docs/ProgrammersManual.html +++ b/docs/ProgrammersManual.html @@ -129,7 +129,7 @@ with another Value
  • The AbstractTypeUser Class
    • -
  • The SymbolTable class
    • +
  • The ValueSymbolTable and TypeSymbolTable classes
  • The Core LLVM Class Hierarchy Reference @@ -2045,12 +2045,8 @@ Type is maintained by PATypeHolder objects.

    Some data structures need more to perform more complex updates when types get -resolved. The SymbolTable class, for example, needs -move and potentially merge type planes in its representation when a pointer -changes.

    - -

    -To support this, a class can derive from the AbstractTypeUser class. This class +resolved. To support this, a class can derive from the AbstractTypeUser class. +This class allows it to get callbacks when certain types are resolved. To register to get callbacks for a particular type, the DerivedType::{add/remove}AbstractTypeUser methods can be called on a type. Note that these methods only work for @@ -2062,16 +2058,19 @@ objects) can never be refined.

    - The SymbolTable class + The ValueSymbolTable and + TypeSymbolTable classes
    -

    This class provides a symbol table that the The +ValueSymbolTable class provides a symbol table that the Function and -Module classes use for naming definitions. The symbol table can -provide a name for any Value. -SymbolTable is an abstract data type. It hides the data it contains -and provides access to it through a controlled interface.

    +Module classes use for naming value definitions. The symbol table +can provide a name for any Value. +The +TypeSymbolTable class is used by the Module class to store +names for types.

    Note that the SymbolTable class should not be directly accessed by most clients. It should only be used when iteration over the symbol table @@ -2081,140 +2080,14 @@ all LLVM an empty name) do not exist in the symbol table.

    -

    To use the SymbolTable well, you need to understand the -structure of the information it holds. The class contains two -std::map objects. The first, pmap, is a map of -Type* to maps of name (std::string) to Value*. -Thus, Values are stored in two-dimensions and accessed by Type and -name.

    - -

    The interface of this class provides three basic types of operations: -

      -
    1. Accessors. Accessors provide read-only access to information - such as finding a value for a name with the - lookup method.
      2. -
    2. Mutators. Mutators allow the user to add information to the - SymbolTable with methods like - insert.
      3. -
    3. Iterators. Iterators allow the user to traverse the content - of the symbol table in well defined ways, such as the method - plane_begin.
      4. -
    - -

    Accessors

    -
    -
    Value* lookup(const Type* Ty, const std::string& name) const: -
    -
    The lookup method searches the type plane given by the - Ty parameter for a Value with the provided name. - If a suitable Value is not found, null is returned.
    - -
    bool isEmpty() const:
    -
    This function returns true if both the value and types maps are - empty
    -
    - -

    Mutators

    -
    -
    void insert(Value *Val):
    -
    This method adds the provided value to the symbol table. The Value must - have both a name and a type which are extracted and used to place the value - in the correct type plane under the value's name.
    - -
    void remove(Value* Val):
    -
    This method removes a named value from the symbol table. The - type and name of the Value are extracted from \p N and used to - lookup the Value in the correct type plane. If the Value is - not in the symbol table, this method silently ignores the - request.
    - -
    - -

    Iteration

    -

    The following functions describe three types of iterators you can obtain -the beginning or end of the sequence for both const and non-const. It is -important to keep track of the different kinds of iterators. There are -three idioms worth pointing out:

    - - - - - - - - - - - -
    UnitsIteratorIdiom
    Planes Of name/Value mapsPI
    
-for (SymbolTable::plane_const_iterator PI = ST.plane_begin(),
-     PE = ST.plane_end(); PI != PE; ++PI ) {
-  PI->first  // This is the Type* of the plane
-  PI->second // This is the SymbolTable::ValueMap of name/Value pairs
-}
-
    name/Value pairs in a planeVI
    
-for (SymbolTable::value_const_iterator VI = ST.value_begin(SomeType),
-     VE = ST.value_end(SomeType); VI != VE; ++VI ) {
-  VI->first  // This is the name of the Value
-  VI->second // This is the Value* value associated with the name
-}
-
    +

    These symbol tables support iteration over the values/types in the symbol +table with begin/end/iterator and supports querying to see if a +specific name is in the symbol table (with lookup). The +ValueSymbolTable class exposes no public mutator methods, instead, +simply call setName on a value, which will autoinsert it into the +appropriate symbol table. For types, use the Module::addTypeName method to +insert entries into the symbol table.

    -

    Using the recommended iterator names and idioms will help you avoid -making mistakes. Of particular note, make sure that whenever you use -value_begin(SomeType) that you always compare the resulting iterator -with value_end(SomeType) not value_end(SomeOtherType) or else you -will loop infinitely.

    - -
    - -
    plane_iterator plane_begin():
    -
    Get an iterator that starts at the beginning of the type planes. - The iterator will iterate over the Type/ValueMap pairs in the - type planes.
    - -
    plane_const_iterator plane_begin() const:
    -
    Get a const_iterator that starts at the beginning of the type - planes. The iterator will iterate over the Type/ValueMap pairs - in the type planes.
    - -
    plane_iterator plane_end():
    -
    Get an iterator at the end of the type planes. This serves as - the marker for end of iteration over the type planes.
    - -
    plane_const_iterator plane_end() const:
    -
    Get a const_iterator at the end of the type planes. This serves as - the marker for end of iteration over the type planes.
    - -
    value_iterator value_begin(const Type *Typ):
    -
    Get an iterator that starts at the beginning of a type plane. - The iterator will iterate over the name/value pairs in the type plane. - Note: The type plane must already exist before using this.
    - -
    value_const_iterator value_begin(const Type *Typ) const:
    -
    Get a const_iterator that starts at the beginning of a type plane. - The iterator will iterate over the name/value pairs in the type plane. - Note: The type plane must already exist before using this.
    - -
    value_iterator value_end(const Type *Typ):
    -
    Get an iterator to the end of a type plane. This serves as the marker - for end of iteration of the type plane. - Note: The type plane must already exist before using this.
    - -
    value_const_iterator value_end(const Type *Typ) const:
    -
    Get a const_iterator to the end of a type plane. This serves as the - marker for end of iteration of the type plane. - Note: the type plane must already exist before using this.
    - -
    plane_const_iterator find(const Type* Typ ) const:
    -
    This method returns a plane_const_iterator for iteration over - the type planes starting at a specific plane, given by \p Ty.
    - -
    plane_iterator find( const Type* Typ :
    -
    This method returns a plane_iterator for iteration over the - type planes starting at a specific plane, given by \p Ty.
    - -
    -- 2.34.1