Displaying 20 results from an estimated 20 matches for "fieldptr".
2004 Jul 21
2
[LLVMdev] GC questions.
...wo pointers in instead of
a pointer and offset. This allows the front-end to emit target-generic
code instead of target-specific code (where it would have to know the
offset to the field). To be more specific, llvm_gc_read should look like
this by default:
void *llvm_gc_read(void *ObjPtr, void **FieldPtr) {
return *FieldPtr;
}
Also, please don't forget to update docs/GarbageCollection.html and
LangRef.html
Thanks for the help, sorry I didn't mention this before. :)
-Chris
--
http://llvm.cs.uiuc.edu/
http://nondot.org/sabre/
2004 Jul 21
0
[LLVMdev] GC questions.
...; a pointer and offset. This allows the front-end to emit target-generic
> code instead of target-specific code (where it would have to know the
> offset to the field). To be more specific, llvm_gc_read should look like
> this by default:
>
> void *llvm_gc_read(void *ObjPtr, void **FieldPtr) {
> return *FieldPtr;
> }
Hm, but doesn't FieldPtr need to be calculated target-specific in those
cases?
My thoughts was that it's better to just have one pointer to the heap, and
reference fields by offset, rather than alloca'ing memory for each
FieldPtr needed (to make sure...
2004 Jul 21
2
[LLVMdev] GC questions.
On Wed, 21 Jul 2004, Tobias Nurmiranta wrote:
> > void *llvm_gc_read(void *ObjPtr, void **FieldPtr) {
> > return *FieldPtr;
> > }
>
> Hm, but doesn't FieldPtr need to be calculated target-specific in those
> cases?
For the field pointer, one could use the getelementptr instruction:
%pairty = { sbyte, sbyte, int* }
%pairPtr = ...
%fieldptr = getelementptr %pairty...
2004 Jul 21
0
[LLVMdev] GC questions.
Ok, that makes sense :).
, Tobias
On Wed, 21 Jul 2004, Chris Lattner wrote:
> On Wed, 21 Jul 2004, Tobias Nurmiranta wrote:
> > > void *llvm_gc_read(void *ObjPtr, void **FieldPtr) {
> > > return *FieldPtr;
> > > }
> >
> > Hm, but doesn't FieldPtr need to be calculated target-specific in those
> > cases?
>
> For the field pointer, one could use the getelementptr instruction:
>
> %pairty = { sbyte, sbyte, int* }
>
>...
2008 Apr 28
2
[LLVMdev] getting started with IR needing GC
On Sun, 2008-04-27 at 22:34 -0400, Gordon Henriksen wrote:
> On 2008-04-27, at 21:29, Lane Schwartz wrote:
> > Since this is a simple copying collector, the functions llvm_gc_read
> > and llvm_gc_write won't really do much:
> > void *llvm_gc_read(void *ObjPtr, void **FieldPtr) { return
> > *FieldPtr; }
> > void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
> > { *FieldPtr = V; }
>
> You can just emit loads and stores directly if your read/write
> barriers do nothing. Also, there's nothing special about the
> llvm_gc_rea...
2008 Apr 28
3
[LLVMdev] getting started with IR needing GC
...c_initialize. This
function uses the system calloc to allocate two big blocks of memory,
then stores pointers to that memory in static variables.
Since this is a simple copying collector, the functions llvm_gc_read
and llvm_gc_write won't really do much:
void *llvm_gc_read(void *ObjPtr, void **FieldPtr) { return *FieldPtr; }
void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr) { *FieldPtr = V; }
There is also a function called llvm_gc_allocate. Now, instead of
using alloca or malloc, my frontend generates a call to
llvm_gc_allocate.
Up to this point I feel pretty good about what's goi...
2008 Apr 28
0
[LLVMdev] getting started with IR needing GC
...and prototypes it likes to provide this functionality. A bump-
ptr allocator might easily inline part of its allocation routine.
> Since this is a simple copying collector, the functions llvm_gc_read
> and llvm_gc_write won't really do much:
> void *llvm_gc_read(void *ObjPtr, void **FieldPtr) { return
> *FieldPtr; }
> void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
> { *FieldPtr = V; }
You can just emit loads and stores directly if your read/write
barriers do nothing. Also, there's nothing special about the
llvm_gc_read or llvm_gc_write functions any mo...
2006 Feb 27
4
[LLVMdev] Garbage collection questions
Couple of questions:
1. void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
I haven't seen an adequate explanation of these, but I'm guessing:
void *V: value being written to the field
void *ObjPtr: current value of the field (ie. ObjPtr == *FieldPtr
upon entry to llvm_gc_write)
void **FieldPtr: address of the field being written
2. The current semispace c...
2006 Feb 27
0
[LLVMdev] Garbage collection questions
On Mon, 27 Feb 2006, Sandro Magi wrote:
> Couple of questions:
Ok, it's been a long while since I've worked on the GC stuff, but I'll try
to help :)
> 1. void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
>
> I haven't seen an adequate explanation of these, but I'm guessing:
> void *V: value being written to the field
> void *ObjPtr: current value of the field (ie. ObjPtr == *FieldPtr
> upon entry to llvm_gc_write)
> void **FieldPtr: address of the field being written...
2004 Jul 22
2
[LLVMdev] GC questions.
...ots are
implemented.
, Tobias
On Wed, 21 Jul 2004, Tobias Nurmiranta wrote:
>
> Ok, that makes sense :).
> , Tobias
>
> On Wed, 21 Jul 2004, Chris Lattner wrote:
>
> > On Wed, 21 Jul 2004, Tobias Nurmiranta wrote:
> > > > void *llvm_gc_read(void *ObjPtr, void **FieldPtr) {
> > > > return *FieldPtr;
> > > > }
> > >
> > > Hm, but doesn't FieldPtr need to be calculated target-specific in those
> > > cases?
> >
> > For the field pointer, one could use the getelementptr instruction:
> >
> >...
2008 Apr 28
0
[LLVMdev] getting started with IR needing GC
...2008-04-27 at 22:34 -0400, Gordon Henriksen wrote:
>> On 2008-04-27, at 21:29, Lane Schwartz wrote:
>>> Since this is a simple copying collector, the functions
>>> llvm_gc_read and llvm_gc_write won't really do much:
>>> void *llvm_gc_read(void *ObjPtr, void **FieldPtr) { return
>>> *FieldPtr; }
>>> void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
>>> { *FieldPtr = V; }
>>
>> You can just emit loads and stores directly if your read/write
>> barriers do nothing. Also, there's nothing special about th...
2009 Jan 09
2
[LLVMdev] RFC: Store alignment should be LValue alignment, not source alignment
...ue TreeToLLVM::EmitLV_COMPONENT_REF(
// Compute the byte offset, and add it to the pointer.
unsigned ByteOffset = NumAlignmentUnits*ByteAlignment;
+ LVAlign = MinAlign(LVAlign, ByteOffset);
Constant *Offset = ConstantInt::get(TD.getIntPtrType(),
ByteOffset);
FieldPtr = CastToType(Instruction::PtrToInt, FieldPtr,
@@ -6242,17 +6282,18 @@ LValue TreeToLLVM::EmitLV_COMPONENT_REF(
// Okay, everything is good. Return this as a bitfield if we
can't
// return it as a normal l-value. (e.g. "struct X { int X :
32 };" ).
+ // Conservativ...
2006 Feb 27
0
[LLVMdev] Garbage collection questions
Couple of questions:
1. void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
I haven't seen an adequate explanation of these, but I'm guessing:
void *V: value being written to the field
void *ObjPtr: current value of the field (ie. ObjPtr == *FieldPtr upon
entry to llvm_gc_write)
void **FieldPtr: address of the field being written
2. The current semispace c...
2006 Feb 27
1
[LLVMdev] Garbage collection questions
On 2/27/06, Chris Lattner <sabre at nondot.org> wrote:
> > 1. void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr)
> >
> > I haven't seen an adequate explanation of these, but I'm guessing:
> > void *V: value being written to the field
> > void *ObjPtr: current value of the field (ie. ObjPtr == *FieldPtr
> > upon entry to llvm_gc_write)
> > void **FieldPtr: addres...
2006 Mar 14
0
[LLVMdev] Re: Garbage collection questions
...r (; head != NULL; head = head->field.next) {
free(head);
/* FIXME: this should also decrement the ref count of all pointers within
* head, which places them in the 'scan' list.
*/
}
}
}
/* We use no read barrier */
void *llvm_gc_read(void *ObjPtr, void **FieldPtr) { return *FieldPtr; }
/* write barrier to increment and decrement refcounts */
void llvm_gc_write(void *V, void *ObjPtr, void **FieldPtr) {
if (ObjPtr != V) { /* skip all this work if simply resetting the field */
void *obj = *FieldPtr;
refcnt_dec(obj);
*FieldPtr = V;
refcnt_inc...
2006 Mar 14
3
[LLVMdev] Re: Garbage collection questions
Again, sorry for the delay. :(
On Thu, 9 Mar 2006, Sandro Magi wrote:
> I've written a reference-counting garbage collector for LLVM, but I'm
> still unclear on a few things.
Cool!
> The following piece of code that appears on
> http://llvm.cs.uiuc.edu/docs/GarbageCollection.html is unclear:
>
> ;; As the pointer goes out of scope, store a null value into
> ;;
2008 Apr 22
0
[LLVMdev] getting started with IR needing GC
Hi Terence,
I think you're getting hung up on the details of the shadow stack
collector. The shadow stack is a GC that is possible within this
framework, but of course could be implemented without any special
support. Its presence is more misleading than anything else. Taking a
step back, the concepts are:
llvm.gcroot instructs the code generator --> My GC needs to be able to
2008 Apr 21
2
[LLVMdev] getting started with IR needing GC
On Apr 20, 2008, at 6:52 PM, Gordon Henriksen wrote:
> On 2008-04-20, at 21:05, Terence Parr wrote:
>
>> On Apr 20, 2008, at 5:36 PM, Gordon Henriksen wrote:
>>
>>> Since the semispace heap doesn't actually work (it's an example,
>>> at best), I suggest you simply copy the stack visitor into your
>>> project; it's only a dozen lines of
2004 Jul 21
0
[LLVMdev] GC questions.
On Wed, 21 Jul 2004, Chris Lattner wrote:
>
> Yes, this makes a tremendous amount of sense. Do you think you could
> prepare some patches to make this happen? If you have any questions, feel
> free to ask :)
Ok, a patch[1] is attached. I didn't care to coerce the offset, since I
assume that it is an uint, but maybe I should? Hopefully I've understood
the llvm source
2004 Jul 21
2
[LLVMdev] GC questions.
On Wed, 21 Jul 2004, Tobias Nurmiranta wrote:
>
> Hi, I'm thinking out loud, please give me some feedback.
>
> Regarding llvm.gcread and llvm.gcwrite, wouldn't it be nicer if they are
> implemented as:
>
> llvm.gcread(sbyte** object, uint offset)
> llvm.gcwrite(sbyte* data, sbyte** object, uint offset)
>
> Where you also have the offset into the object. In