void CodeGen::siBeginBlock(BasicBlock* block)
{
assert(block != nullptr);
if (!compiler->opts.compScopeInfo)
return;
if (compiler->info.compVarScopesCount == 0)
return;
#if FEATURE_EH_FUNCLETS
if (siInFuncletRegion)
return;
if (block->bbFlags & BBF_FUNCLET_BEG)
{
// For now, don't report any scopes in funclets. JIT64 doesn't.
siInFuncletRegion = true;
JITDUMP("Scope info: found beginning of funclet region at block BB%02u; ignoring following blocks\n",
block->bbNum);
return;
}
#endif // FEATURE_EH_FUNCLETS
#ifdef DEBUG
if (verbose)
{
printf("\nScope info: begin block BB%02u, IL range ", block->bbNum);
block->dspBlockILRange();
printf("\n");
}
#endif // DEBUG
unsigned beginOffs = block->bbCodeOffs;
if (beginOffs == BAD_IL_OFFSET)
{
JITDUMP("Scope info: ignoring block beginning\n");
return;
}
if (!compiler->opts.compDbgCode)
{
/* For non-debuggable code */
// End scope of variables which are not live for this block
siUpdate();
// Check that vars which are live on entry have an open scope
VARSET_ITER_INIT(compiler, iter, block->bbLiveIn, i);
while (iter.NextElem(compiler, &i))
{
unsigned varNum = compiler->lvaTrackedToVarNum[i];
// lvRefCnt may go down to 0 after liveness-analysis.
// So we need to check if this tracked variable is actually used.
if (!compiler->lvaTable[varNum].lvIsInReg() && !compiler->lvaTable[varNum].lvOnFrame)
{
assert(compiler->lvaTable[varNum].lvRefCnt == 0);
continue;
}
siCheckVarScope(varNum, beginOffs);
}
}
else
{
// For debuggable code, scopes can begin only on block boundaries.
// Check if there are any scopes on the current block's start boundary.
VarScopeDsc* varScope;
#if FEATURE_EH_FUNCLETS
// If we find a spot where the code offset isn't what we expect, because
// there is a gap, it might be because we've moved the funclets out of
// line. Catch up with the enter and exit scopes of the current block.
// Ignore the enter/exit scope changes of the missing scopes, which for
// funclets must be matched.
if (siLastEndOffs != beginOffs)
{
assert(beginOffs > 0);
assert(siLastEndOffs < beginOffs);
JITDUMP("Scope info: found offset hole. lastOffs=%u, currOffs=%u\n",
siLastEndOffs, beginOffs);
// Skip enter scopes
while ((varScope = compiler->compGetNextEnterScope(beginOffs - 1, true)) != NULL)
{
/* do nothing */
JITDUMP("Scope info: skipping enter scope, LVnum=%u\n", varScope->vsdLVnum);
}
// Skip exit scopes
while ((varScope = compiler->compGetNextExitScope(beginOffs - 1, true)) != NULL)
{
/* do nothing */
JITDUMP("Scope info: skipping exit scope, LVnum=%u\n", varScope->vsdLVnum);
}
}
#else // FEATURE_EH_FUNCLETS
if (siLastEndOffs != beginOffs)
{
assert(siLastEndOffs < beginOffs);
return;
}
#endif // FEATURE_EH_FUNCLETS
while ((varScope = compiler->compGetNextEnterScope(beginOffs)) != NULL)
{
// brace-matching editor workaround for following line: (
JITDUMP("Scope info: opening scope, LVnum=%u [%03X..%03X)\n", varScope->vsdLVnum, varScope->vsdLifeBeg, varScope->vsdLifeEnd);
siNewScope(varScope->vsdLVnum, varScope->vsdVarNum);
#ifdef DEBUG
LclVarDsc* lclVarDsc1 = &compiler->lvaTable[varScope->vsdVarNum];
if (VERBOSE)
{
printf("Scope info: >> new scope, VarNum=%u, tracked? %s, VarIndex=%u, bbLiveIn=%s ",
varScope->vsdVarNum,
lclVarDsc1->lvTracked ? "yes" : "no",
lclVarDsc1->lvVarIndex,
VarSetOps::ToString(compiler, block->bbLiveIn));
dumpConvertedVarSet(compiler, block->bbLiveIn);
printf("\n");
}
assert(!lclVarDsc1->lvTracked || VarSetOps::IsMember(compiler, block->bbLiveIn, lclVarDsc1->lvVarIndex));
#endif // DEBUG
}
}
#ifdef DEBUG
if (verbose)
siDispOpenScopes();
#endif
}
void TreeLifeUpdater<ForCodeGen>::UpdateLifeVar(GenTree* tree)
{
GenTree* indirAddrLocal = compiler->fgIsIndirOfAddrOfLocal(tree);
assert(tree->OperIsNonPhiLocal() || indirAddrLocal != nullptr);
// Get the local var tree -- if "tree" is "Ldobj(addr(x))", or "ind(addr(x))" this is "x", else it's "tree".
GenTree* lclVarTree = indirAddrLocal;
if (lclVarTree == nullptr)
{
lclVarTree = tree;
}
unsigned int lclNum = lclVarTree->gtLclVarCommon.gtLclNum;
LclVarDsc* varDsc = compiler->lvaTable + lclNum;
#ifdef DEBUG
#if !defined(_TARGET_AMD64_)
// There are no addr nodes on ARM and we are experimenting with encountering vars in 'random' order.
// Struct fields are not traversed in a consistent order, so ignore them when
// verifying that we see the var nodes in execution order
if (ForCodeGen)
{
if (tree->OperIsIndir())
{
assert(indirAddrLocal != NULL);
}
else if (tree->gtNext != NULL && tree->gtNext->gtOper == GT_ADDR &&
((tree->gtNext->gtNext == NULL || !tree->gtNext->gtNext->OperIsIndir())))
{
assert(tree->IsLocal()); // Can only take the address of a local.
// The ADDR might occur in a context where the address it contributes is eventually
// dereferenced, so we can't say that this is not a use or def.
}
}
#endif // !_TARGET_AMD64_
#endif // DEBUG
compiler->compCurLifeTree = tree;
VarSetOps::Assign(compiler, newLife, compiler->compCurLife);
// By codegen, a struct may not be TYP_STRUCT, so we have to
// check lvPromoted, for the case where the fields are being
// tracked.
if (!varDsc->lvTracked && !varDsc->lvPromoted)
{
return;
}
// if it's a partial definition then variable "x" must have had a previous, original, site to be born.
bool isBorn = ((tree->gtFlags & GTF_VAR_DEF) != 0 && (tree->gtFlags & GTF_VAR_USEASG) == 0);
bool isDying = ((tree->gtFlags & GTF_VAR_DEATH) != 0);
bool spill = ((tree->gtFlags & GTF_SPILL) != 0);
// Since all tracked vars are register candidates, but not all are in registers at all times,
// we maintain two separate sets of variables - the total set of variables that are either
// born or dying here, and the subset of those that are on the stack
VarSetOps::ClearD(compiler, stackVarDeltaSet);
if (isBorn || isDying)
{
VarSetOps::ClearD(compiler, varDeltaSet);
if (varDsc->lvTracked)
{
VarSetOps::AddElemD(compiler, varDeltaSet, varDsc->lvVarIndex);
if (ForCodeGen)
{
if (isBorn && varDsc->lvIsRegCandidate() && tree->gtHasReg())
{
compiler->codeGen->genUpdateVarReg(varDsc, tree);
}
if (varDsc->lvIsInReg() && tree->gtRegNum != REG_NA)
{
compiler->codeGen->genUpdateRegLife(varDsc, isBorn, isDying DEBUGARG(tree));
}
else
{
VarSetOps::AddElemD(compiler, stackVarDeltaSet, varDsc->lvVarIndex);
}
}
}
else if (varDsc->lvPromoted)
{
// If hasDeadTrackedFieldVars is true, then, for a LDOBJ(ADDR(<promoted struct local>)),
// *deadTrackedFieldVars indicates which tracked field vars are dying.
bool hasDeadTrackedFieldVars = false;
if (indirAddrLocal != nullptr && isDying)
{
assert(!isBorn); // GTF_VAR_DEATH only set for LDOBJ last use.
VARSET_TP* deadTrackedFieldVars = nullptr;
hasDeadTrackedFieldVars =
compiler->LookupPromotedStructDeathVars(indirAddrLocal, &deadTrackedFieldVars);
if (hasDeadTrackedFieldVars)
{
VarSetOps::Assign(compiler, varDeltaSet, *deadTrackedFieldVars);
}
}
for (unsigned i = varDsc->lvFieldLclStart; i < varDsc->lvFieldLclStart + varDsc->lvFieldCnt; ++i)
{
LclVarDsc* fldVarDsc = &(compiler->lvaTable[i]);
noway_assert(fldVarDsc->lvIsStructField);
if (fldVarDsc->lvTracked)
{
unsigned fldVarIndex = fldVarDsc->lvVarIndex;
noway_assert(fldVarIndex < compiler->lvaTrackedCount);
if (!hasDeadTrackedFieldVars)
{
VarSetOps::AddElemD(compiler, varDeltaSet, fldVarIndex);
if (ForCodeGen)
{
// We repeat this call here and below to avoid the VarSetOps::IsMember
// test in this, the common case, where we have no deadTrackedFieldVars.
if (fldVarDsc->lvIsInReg())
{
if (isBorn)
{
compiler->codeGen->genUpdateVarReg(fldVarDsc, tree);
}
compiler->codeGen->genUpdateRegLife(fldVarDsc, isBorn, isDying DEBUGARG(tree));
}
else
{
VarSetOps::AddElemD(compiler, stackVarDeltaSet, fldVarIndex);
}
}
}
else if (ForCodeGen && VarSetOps::IsMember(compiler, varDeltaSet, fldVarIndex))
{
if (compiler->lvaTable[i].lvIsInReg())
{
if (isBorn)
{
compiler->codeGen->genUpdateVarReg(fldVarDsc, tree);
}
compiler->codeGen->genUpdateRegLife(fldVarDsc, isBorn, isDying DEBUGARG(tree));
}
else
{
VarSetOps::AddElemD(compiler, stackVarDeltaSet, fldVarIndex);
}
}
}
}
}
// First, update the live set
if (isDying)
{
// We'd like to be able to assert the following, however if we are walking
// through a qmark/colon tree, we may encounter multiple last-use nodes.
// assert (VarSetOps::IsSubset(compiler, regVarDeltaSet, newLife));
VarSetOps::DiffD(compiler, newLife, varDeltaSet);
}
else
{
// This shouldn't be in newLife, unless this is debug code, in which
// case we keep vars live everywhere, OR the variable is address-exposed,
// OR this block is part of a try block, in which case it may be live at the handler
// Could add a check that, if it's in newLife, that it's also in
// fgGetHandlerLiveVars(compCurBB), but seems excessive
//
// For a dead store, it can be the case that we set both isBorn and isDying to true.
// (We don't eliminate dead stores under MinOpts, so we can't assume they're always
// eliminated.) If it's both, we handled it above.
VarSetOps::UnionD(compiler, newLife, varDeltaSet);
}
}
if (!VarSetOps::Equal(compiler, compiler->compCurLife, newLife))
{
#ifdef DEBUG
if (compiler->verbose)
{
printf("\t\t\t\t\t\t\tLive vars: ");
dumpConvertedVarSet(compiler, compiler->compCurLife);
printf(" => ");
dumpConvertedVarSet(compiler, newLife);
printf("\n");
}
#endif // DEBUG
VarSetOps::Assign(compiler, compiler->compCurLife, newLife);
if (ForCodeGen)
{
// Only add vars to the gcInfo.gcVarPtrSetCur if they are currently on stack, since the
// gcInfo.gcTrkStkPtrLcls
// includes all TRACKED vars that EVER live on the stack (i.e. are not always in a register).
VarSetOps::Assign(compiler, gcTrkStkDeltaSet, compiler->codeGen->gcInfo.gcTrkStkPtrLcls);
VarSetOps::IntersectionD(compiler, gcTrkStkDeltaSet, stackVarDeltaSet);
if (!VarSetOps::IsEmpty(compiler, gcTrkStkDeltaSet))
{
#ifdef DEBUG
if (compiler->verbose)
{
printf("\t\t\t\t\t\t\tGCvars: ");
dumpConvertedVarSet(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur);
printf(" => ");
}
#endif // DEBUG
if (isBorn)
{
VarSetOps::UnionD(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur, gcTrkStkDeltaSet);
}
else
{
VarSetOps::DiffD(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur, gcTrkStkDeltaSet);
}
#ifdef DEBUG
if (compiler->verbose)
{
dumpConvertedVarSet(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur);
printf("\n");
}
#endif // DEBUG
}
#ifdef USING_SCOPE_INFO
compiler->codeGen->siUpdate();
#endif // USING_SCOPE_INFO
}
}
if (ForCodeGen && spill)
{
assert(!varDsc->lvPromoted);
compiler->codeGen->genSpillVar(tree);
if (VarSetOps::IsMember(compiler, compiler->codeGen->gcInfo.gcTrkStkPtrLcls, varDsc->lvVarIndex))
{
if (!VarSetOps::IsMember(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur, varDsc->lvVarIndex))
{
VarSetOps::AddElemD(compiler, compiler->codeGen->gcInfo.gcVarPtrSetCur, varDsc->lvVarIndex);
#ifdef DEBUG
if (compiler->verbose)
{
printf("\t\t\t\t\t\t\tVar V%02u becoming live\n", varDsc - compiler->lvaTable);
}
#endif // DEBUG
}
}
}
}
