From fac8de1fde1dac1f78a7f2e22c536a9781f9a246 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emmanuel=20Beno=C3=AEt?= <tseeker@nocternity.net>
Date: Fri, 8 Dec 2017 22:00:43 +0100
Subject: [PATCH] Optimizer - Mostly OK use/define chain construction
In which "mostly" means that it will work, unless:
1/ something is used before being defined (will trigger assertion)
2/ a local variable is re-used before being redefined, which will
be detected as using the def from the previous execution (won't be a
problem for now as it'll crash first, due to (1))
---
c-opopt.cc | 41 ++++++++++++++++++++++++++++++++---------
1 file changed, 32 insertions(+), 9 deletions(-)
diff --git a/c-opopt.cc b/c-opopt.cc
index a0dd4c4..49c706c 100644
--- a/c-opopt.cc
+++ b/c-opopt.cc
@@ -692,6 +692,7 @@ void T_OptData::buildUseDefineChains(
auto& resource{ varUDChains[ rec.entry ] };
const auto defId{ (*activeDefs)[ rec.entry ] };
// FIXME: must be defined
+ assert( defId != T_HashIndex::INVALID_INDEX );
resource.defines[ defId ].refs.add( rec.index );
resource.uses[ rec.index ].refs.add( defId );
logger( [&](){
@@ -712,7 +713,7 @@ void T_OptData::buildUseDefineChains(
(*activeDefs)[ rec.entry ] = rec.index;
logger( [&](){
T_StringBuilder sb;
- sb << "DEF " << rec.index
+ sb << "DEF " << rec.index << ' '
<< varUDChains[ rec.entry ].var.name
<< " @ instr #" << ii;
return sb;
@@ -726,10 +727,6 @@ void T_OptData::buildUseDefineChains(
}
// Check for possible next nodes
- // -> no output nodes left -> pop stack and keep trying,
- // unless we've already processed all nodes
- // -> if there's only one, use it and don't push to stack
- // -> otherwise push to stack, use first available node
do {
auto const& rcn{ *ctrlFlowGraph[ node ] };
const uint32_t nSuccs{ [&](){
@@ -742,23 +739,49 @@ void T_OptData::buildUseDefineChains(
}
return c;
}() };
- logger( [=]() {
+ logger( [&]() {
T_StringBuilder sb;
sb << "node " << node << ": " << nSuccs
- << " successor(s) left";
+ << " successor(s) left (stack depth "
+ << stack.size( ) << ')';
return sb;
} , LL2 );
+ // -> no output nodes left -> pop stack and keep trying,
+ // unless we've already processed all nodes
if ( nSuccs == 0 ) {
assert( !stack.empty( ) );
node = stack.last( ).node;
activeDefs = std::move( stack.last( ).def );
stack.removeLast( );
+ logger( [&]() {
+ T_StringBuilder sb;
+ sb << "pop stack -> next node " << node
+ << " (stack depth "
+ << stack.size( ) << ')';
+ return sb;
+ } , LL2 );
continue;
}
- // TODO cases in which there is one or more successors
- } while ( 0 ); // XXX
+ const auto no{ rcn.outbound.size( ) };
+ uint32_t nn{ T_HashIndex::INVALID_INDEX };
+ for ( auto i = 0u ; i < no ; i ++ ) {
+ if ( !processedNodes[ rcn.outbound[ i ] ] ) {
+ nn = rcn.outbound[ i ];
+ break;
+ }
+ }
+
+ // More than one possible successor? Push to stack
+ if ( nSuccs > 1 ) {
+ M_LOGSTR_( "pushing node" , LL2 );
+ stack.addNew( activeDefs , node );
+ }
+
+ node = nn;
+ break;
+ } while ( 1 );
// 30 if next block is an end of function, kill locals
}