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6809798: SafePointScalarObject node placed into incorrect block during GCM

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Replace the control edge of a pinned node before scheduling.

Reviewed-by: never
This commit is contained in:
Vladimir Kozlov 2009-02-26 14:26:02 -08:00
parent f7098831dd
commit 9b31d58b98
6 changed files with 52 additions and 27 deletions
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67
hotspot/src/share/vm/opto/gcm.cpp
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@ -57,6 +57,37 @@ void PhaseCFG::schedule_node_into_block( Node *n, Block *b ) {
}
}
//----------------------------replace_block_proj_ctrl-------------------------
// Nodes that have is_block_proj() nodes as their control need to use
// the appropriate Region for their actual block as their control since
// the projection will be in a predecessor block.
void PhaseCFG::replace_block_proj_ctrl( Node *n ) {
const Node *in0 = n->in(0);
assert(in0 != NULL, "Only control-dependent");
const Node *p = in0->is_block_proj();
if (p != NULL && p != n) { // Control from a block projection?
assert(!n->pinned() || n->is_SafePointScalarObject(), "only SafePointScalarObject pinned node is expected here");
// Find trailing Region
Block *pb = _bbs[in0->_idx]; // Block-projection already has basic block
uint j = 0;
if (pb->_num_succs != 1) { // More then 1 successor?
// Search for successor
uint max = pb->_nodes.size();
assert( max > 1, "" );
uint start = max - pb->_num_succs;
// Find which output path belongs to projection
for (j = start; j < max; j++) {
if( pb->_nodes[j] == in0 )
break;
}
assert( j < max, "must find" );
// Change control to match head of successor basic block
j -= start;
}
n->set_req(0, pb->_succs[j]->head());
}
}
//------------------------------schedule_pinned_nodes--------------------------
// Set the basic block for Nodes pinned into blocks
@ -68,8 +99,10 @@ void PhaseCFG::schedule_pinned_nodes( VectorSet &visited ) {
Node *n = spstack.pop();
if( !visited.test_set(n->_idx) ) { // Test node and flag it as visited
if( n->pinned() && !_bbs.lookup(n->_idx) ) { // Pinned? Nail it down!
assert( n->in(0), "pinned Node must have Control" );
// Before setting block replace block_proj control edge
replace_block_proj_ctrl(n);
Node *input = n->in(0);
assert( input, "pinned Node must have Control" );
while( !input->is_block_start() )
input = input->in(0);
Block *b = _bbs[input->_idx]; // Basic block of controlling input
@ -158,34 +191,12 @@ bool PhaseCFG::schedule_early(VectorSet &visited, Node_List &roots) {
uint i = nstack_top_i;
if (i == 0) {
// Special control input processing.
// While I am here, go ahead and look for Nodes which are taking control
// from a is_block_proj Node. After I inserted RegionNodes to make proper
// blocks, the control at a is_block_proj more properly comes from the
// Region being controlled by the block_proj Node.
// Fixup some control. Constants without control get attached
// to root and nodes that use is_block_proj() nodes should be attached
// to the region that starts their block.
const Node *in0 = n->in(0);
if (in0 != NULL) { // Control-dependent?
const Node *p = in0->is_block_proj();
if (p != NULL && p != n) { // Control from a block projection?
// Find trailing Region
Block *pb = _bbs[in0->_idx]; // Block-projection already has basic block
uint j = 0;
if (pb->_num_succs != 1) { // More then 1 successor?
// Search for successor
uint max = pb->_nodes.size();
assert( max > 1, "" );
uint start = max - pb->_num_succs;
// Find which output path belongs to projection
for (j = start; j < max; j++) {
if( pb->_nodes[j] == in0 )
break;
}
assert( j < max, "must find" );
// Change control to match head of successor basic block
j -= start;
}
n->set_req(0, pb->_succs[j]->head());
}
replace_block_proj_ctrl(n);
} else { // n->in(0) == NULL
if (n->req() == 1) { // This guy is a constant with NO inputs?
n->set_req(0, _root);
@ -226,6 +237,8 @@ bool PhaseCFG::schedule_early(VectorSet &visited, Node_List &roots) {
if (!n->pinned()) {
// Set earliest legal block.
_bbs.map(n->_idx, find_deepest_input(n, _bbs));
} else {
assert(_bbs[n->_idx] == _bbs[n->in(0)->_idx], "Pinned Node should be at the same block as its control edge");
}
if (nstack.is_empty()) {