llvm-6502/docs/ChrisNotes.txt
Chris Lattner 3ea734986e *** empty log message ***
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131 91177308-0d34-0410-b5e6-96231b3b80d8
2001-07-03 15:27:41 +00:00

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* Fix DCE to elminate br <c>, %L1, %L1 so that it can optimize the main of
fib.ll better. Currently I have to do this to get best results:
as < fib.ll | opt -inline -sccp -dce -sccp -dce |dis
* Fix DCE to work better, so that SCCP can show it's true value.
* Implement ADCE
* Fix the const pool printer to print out constants in some sort of "sorted"
order. Then enable TestOptimizer.sh to diff -sccp output. Currently it
doesn't work because the diff fails because of ordering of the constant
pool. :(
* Enable DoConstantPoolMerging to do trivial DCE of constant values.
* Should provide "castTerminator, castPHI, etc" functions in Instruction, and
similar functions in other classes, that effectively do dynamic casts. This
would allow code like this:
if (I->isTerminator()) {
TerminatorInst *TI = (TerminatorInst*)I;
...
}
to be written as:
if (TerminatorInst *TI = I->castTerminatorInst()) {
...
}
* Think about whether edge split SSA form would be useful to do.
* Inlining should attempt to give block names the same name in the inlined
method (using SymbolTable::getUniqueName)
* The dropAllReferences code can be a noop when NDEBUG!!!
* Finish xvcg output
* pred/succ iterators on basic blocks don't handle switch statements correctly
* Enhance BB to make predecessor handling easier (to update PHI nodes)
* Provide a pass that eliminates critical edges from the CFG
* Provide a print pass to print out xvcg format files for vis
* I need to provide an option to the bytecode loader to ignore memory
dependance edges. Instead, the VM would just treat memory operations
(load, store, getfield, putfield, call) as pinned instructions.
* I need to have a way to prevent taking the address of a constant pool
reference. You should only be able to take the address of a variable.
Maybe taking the address of a constant copies it? What about virtual
function tables? Maybe a const pointer would be better...
* Structures should be accessed something like this: ubyte is ok. Limits
structure size to 256 members. This can be fixed later by either:
1. adding varient that takes ushort
2. Splitting structures into nested structures each of half size
<float> %f = load *{int, {float}} Str, 1, 0
store float %f, *{int, {float}} Str, 1, 0
* I'm noticing me writing a lot of code that looks like this (dtor material here):
ConstPool.dropAllReferences();
ConstPool.delete_all();
ConstPool.setParent(0);
~ConstPool
* Need a way to attach bytecode block info at various levels of asm code.
* Rename "ConstantPool" to "ConstPool"
* Maybe ConstantPool objects should keep themselves sorted as things are
inserted.
* Need to be able to inflate recursive types. %x = { *%x }, %x = %x ()
* Recognize and save comments in assembly and bytecode format
* Encode line number table in bytecode (like #line), optional table
* Encode negative relative offsets in the bytecode file
* Implement switch to switch on a constant pool array of type:
[{ label, int }] or [label] (lookup vs index switch)
* Apparently bison has a %pure_parser option. Maybe useful for Assembly/Parser
* Implement a header file that can read either assembly or bytecode, implement
a writer that can output either based on what is read with this reader..
* Implement the following derived types:
* structure/record { int %foo, int %bar} or { %foo = int, int }
* pointer int *
* "packed format", like this: [4 x sbyte]: Packed SIMD datatype
* Maybe 'tailcall' also?
* Include a method level bytecode block that defines a mapping between values
and registers that defines a minimally register allocated code. This can
make me finally address how to encode extensions in assembly.
* Bytecode reader should use extensions that may or may not be linked into the
application to read blocks. Thus an easy way to ignore symbol table info
would be to not link in that reader into the app.