mirror of
https://github.com/RPCS3/llvm.git
synced 2024-12-12 14:20:33 +00:00
a2204e1ff2
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2776 91177308-0d34-0410-b5e6-96231b3b80d8
73 lines
3.4 KiB
Plaintext
73 lines
3.4 KiB
Plaintext
Changes:
|
|
* Change the casting code to be const correct. Now, doing this is invalid:
|
|
const Value *V = ...;
|
|
Instruction *I = dyn_cast<Instruction>(V);
|
|
instead, the second line should be:
|
|
const Instruction *I = dyn_cast<Instruction>(V);
|
|
|
|
* Change the casting code to allow casting a reference value thus:
|
|
const Value &V = ...;
|
|
Instruction &I = cast<Instruction>(V);
|
|
|
|
dyn_cast does not work with references, because it must return a null pointer
|
|
on failure.
|
|
|
|
* Fundamentally change how instructions and other values are represented.
|
|
Before, every llvm container was an instance of the ValueHolder template,
|
|
instantiated for each container type. This ValueHolder was effectively a
|
|
wrapper around a vector of pointers to the sub-objects.
|
|
|
|
Now, instead of having a vector to pointers of objects, the objects are
|
|
maintained in a doubly linked list of values (ie each Instruction now has
|
|
Next & Previous fields). The containers are now instances of ilist (intrusive
|
|
linked list class), which use the next and previous fields to chain them
|
|
together. The advantage of this implementation is that iterators can be
|
|
formed directly from pointers to the LLVM value, and invalidation is much
|
|
easier to handle.
|
|
|
|
* As part of the above change, dereferencing an iterator (for example:
|
|
BasicBlock::iterator) now produces a reference to the underlying type (same
|
|
example: Instruction&) instead of a pointer to the underlying object. This
|
|
makes it much easier to write nested loops that iterator over things, changing
|
|
this:
|
|
|
|
for (Function::iterator BI = Func->begin(); BI != Func->end(); ++BI)
|
|
for (BasicBlock::iterator II = (*BI)->begin(); II != (*BI)->end(); ++II)
|
|
(*II)->dump();
|
|
|
|
into:
|
|
|
|
for (Function::iterator BI = Func->begin(); BI != Func->end(); ++BI)
|
|
for (BasicBlock::iterator II = BI->begin(); II != BI->end(); ++II)
|
|
II->dump();
|
|
|
|
which is much more natural and what users expect.
|
|
|
|
* Simplification of #include's: Before, it was neccesary for a .cpp file to
|
|
include every .h file that it used. Now things are batched a little bit more
|
|
to make it easier to use. Specifically, the include graph now includes these
|
|
edges:
|
|
Module.h -> Function.h, GlobalVariable.h
|
|
Function.h -> BasicBlock.h, Argument.h
|
|
BasicBlock.h -> Instruction.h
|
|
|
|
Which means that #including Function.h is usually sufficient for getting the
|
|
lower level #includes.
|
|
|
|
* Printing out a Value* has now changed: Printing a Value* will soon print out
|
|
the address of the value instead of the contents of the Value. To print out
|
|
the contents, you must convert it to a reference with (for example)
|
|
'cout << *I' instead of 'cout << I;'. This conversion is not yet complete,
|
|
but will be eventually. In the mean time, both forms print out the contents.
|
|
|
|
* References are used much more throughout the code base. In general, if a
|
|
pointer is known to never be null, it is passed in as a reference instead of a
|
|
pointer. For example, the instruction visitor class uses references instead
|
|
of pointers, and that Pass subclasses now all receive references to Values
|
|
instead of pointers, because they may never be null.
|
|
|
|
* The Function class now has helper functions for accessing the Arguments list.
|
|
Instead of having to go through getArgumentList for simple things like
|
|
iterator over the arguments, now the a*() methods can be used to access them.
|
|
|