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Added updated task launch implementation that now tracks task groups.

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Within each function that launches tasks, we now can easily track which
tasks that function launched, so that the sync at the end of the function
can just sync on the tasks launched by that function (not all tasks
launched by all functions.)

Implementing this led to a rework of the task system API that ispc generates
code to call; the example task systems in examples/tasksys.cpp have been
updated to conform to this API.  (The updated API is also documented in
the ispc user's guide.)

As part of this, "launch[n]" syntax was added to launch a number of tasks
in a single launch statement, rather than requiring a loop over 'n' to
launch n tasks.

This commit thus fixes issue #84 (enhancement to launch multiple tasks from
a single launch statement) as well as issue #105 (recursive task launches
were broken).
This commit is contained in:
Matt Pharr
2011-09-30 11:20:53 -07:00
parent 5ee4d7fce8
commit cb7976bbf6
43 changed files with 1309 additions and 1043 deletions
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102
ctx.cpp
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@@ -144,6 +144,11 @@ FunctionEmitContext::FunctionEmitContext(const Type *rt, llvm::Function *functio
returnedLanesPtr = AllocaInst(LLVMTypes::MaskType, "returned_lanes_memory");
StoreInst(LLVMMaskAllOff, returnedLanesPtr);
launchedTasks = false;
launchGroupHandlePtr = AllocaInst(LLVMTypes::VoidPointerType, "launch_group_handle");
StoreInst(llvm::Constant::getNullValue(LLVMTypes::VoidPointerType),
launchGroupHandlePtr);
if (!returnType || returnType == AtomicType::Void)
returnValuePtr = NULL;
else {
@@ -174,8 +179,6 @@ FunctionEmitContext::FunctionEmitContext(const Type *rt, llvm::Function *functio
StartScope();
}
launchedTasks = false;
// connect the funciton's mask memory to the __mask symbol
Symbol *maskSymbol = m->symbolTable->LookupVariable("__mask");
assert(maskSymbol != NULL);
@@ -759,7 +762,7 @@ FunctionEmitContext::I1VecToBoolVec(llvm::Value *b) {
llvm::Value *
FunctionEmitContext::EmitMalloc(LLVM_TYPE_CONST llvm::Type *ty, int align) {
FunctionEmitContext::SizeOf(LLVM_TYPE_CONST llvm::Type *ty) {
// Emit code to compute the size of the given type using a GEP with a
// NULL base pointer, indexing one element of the given type, and
// casting the resulting 'pointer' to an int giving its size.
@@ -776,24 +779,7 @@ FunctionEmitContext::EmitMalloc(LLVM_TYPE_CONST llvm::Type *ty, int align) {
#endif
AddDebugPos(poffset);
llvm::Value *sizeOf = PtrToIntInst(poffset, LLVMTypes::Int64Type, "offset_int");
// And given the size, call the malloc function
llvm::Function *fmalloc = m->module->getFunction("ISPCMalloc");
assert(fmalloc != NULL);
llvm::Value *mem = CallInst(fmalloc, sizeOf, LLVMInt32(align),
"raw_argmem");
// Cast the void * back to the result pointer type
return BitCastInst(mem, ptrType, "mem_bitcast");
}
void
FunctionEmitContext::EmitFree(llvm::Value *ptr) {
llvm::Value *freeArg = BitCastInst(ptr, LLVMTypes::VoidPointerType,
"argmemfree");
llvm::Function *ffree = m->module->getFunction("ISPCFree");
assert(ffree != NULL);
CallInst(ffree, freeArg);
return sizeOf;
}
@@ -1912,15 +1898,9 @@ FunctionEmitContext::CallInst(llvm::Function *func, llvm::Value *arg0,
llvm::Instruction *
FunctionEmitContext::ReturnInst() {
if (launchedTasks) {
// Automatically add a sync call at the end of any function that
// launched tasks
SourcePos noPos;
noPos.name = "__auto_sync";
ExprStmt *es = new ExprStmt(new SyncExpr(noPos), noPos);
es->EmitCode(this);
delete es;
}
if (launchedTasks)
// Add a sync call at the end of any function that launched tasks
SyncInst();
llvm::Instruction *rinst = NULL;
if (returnValuePtr != NULL) {
@@ -1943,7 +1923,8 @@ FunctionEmitContext::ReturnInst() {
llvm::Instruction *
FunctionEmitContext::LaunchInst(llvm::Function *callee,
std::vector<llvm::Value *> &argVals) {
std::vector<llvm::Value *> &argVals,
llvm::Value *launchCount) {
if (callee == NULL) {
assert(m->errorCount > 0);
return NULL;
@@ -1960,29 +1941,15 @@ FunctionEmitContext::LaunchInst(llvm::Function *callee,
static_cast<LLVM_TYPE_CONST llvm::StructType *>(pt->getElementType());
assert(argStructType->getNumElements() == argVals.size() + 1);
llvm::Function *falloc = m->module->getFunction("ISPCAlloc");
assert(falloc != NULL);
int align = 4 * RoundUpPow2(g->target.nativeVectorWidth);
llvm::Value *argmem;
#ifdef ISPC_IS_WINDOWS
// Use malloc() to allocate storage on Windows, since the stack is
// generally not big enough there to do enough allocations for lots of
// tasks and then things crash horribly...
argmem = EmitMalloc(argStructType, align);
#else
// Otherwise, use alloca for space for the task args, ** unless we're
// compiling to AVX, in which case we use malloc after all **. (See
// http://llvm.org/bugs/show_bug.cgi?id=10841 for details. There are
// limitations in LLVM with respect to dynamic allocas of this sort
// when the stack also has to be 32-byte aligned...).
if (g->target.isa == Target::AVX)
argmem = EmitMalloc(argStructType, align);
else
// KEY DETAIL: pass false to the call of
// FunctionEmitContext::AllocaInst so that the alloca doesn't
// happen just once at the top of the function, but happens each
// time the enclosing basic block executes.
argmem = AllocaInst(argStructType, "argmem", align, false);
#endif // ISPC_IS_WINDOWS
llvm::Value *voidmem = BitCastInst(argmem, LLVMTypes::VoidPointerType);
std::vector<llvm::Value *> allocArgs;
allocArgs.push_back(launchGroupHandlePtr);
allocArgs.push_back(SizeOf(argStructType));
allocArgs.push_back(LLVMInt32(align));
llvm::Value *voidmem = CallInst(falloc, allocArgs, "args_ptr");
llvm::Value *argmem = BitCastInst(voidmem, pt);
// Copy the values of the parameters into the appropriate place in
// the argument block
@@ -2004,5 +1971,32 @@ FunctionEmitContext::LaunchInst(llvm::Function *callee,
llvm::Value *fptr = BitCastInst(callee, LLVMTypes::VoidPointerType);
llvm::Function *flaunch = m->module->getFunction("ISPCLaunch");
assert(flaunch != NULL);
return CallInst(flaunch, fptr, voidmem, "");
std::vector<llvm::Value *> args;
args.push_back(launchGroupHandlePtr);
args.push_back(fptr);
args.push_back(voidmem);
args.push_back(launchCount);
return CallInst(flaunch, args, "");
}
void
FunctionEmitContext::SyncInst() {
llvm::Value *launchGroupHandle = LoadInst(launchGroupHandlePtr, NULL);
llvm::Value *nullPtrValue = llvm::Constant::getNullValue(LLVMTypes::VoidPointerType);
llvm::Value *nonNull = CmpInst(llvm::Instruction::ICmp,
llvm::CmpInst::ICMP_NE,
launchGroupHandle, nullPtrValue);
llvm::BasicBlock *bSync = CreateBasicBlock("call_sync");
llvm::BasicBlock *bPostSync = CreateBasicBlock("post_sync");
BranchInst(bSync, bPostSync, nonNull);
SetCurrentBasicBlock(bSync);
llvm::Function *fsync = m->module->getFunction("ISPCSync");
if (fsync == NULL)
FATAL("Couldn't find ISPCSync declaration?!");
CallInst(fsync, launchGroupHandle, "");
BranchInst(bPostSync);
SetCurrentBasicBlock(bPostSync);
}