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Add EdgeBundles to SplitKit.

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Edge bundles is an annotation on the CFG that turns it into a bipartite directed
graph where each basic block is connected to an outgoing and an ingoing bundle.
These bundles are useful for identifying regions of the CFG for live range
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122301 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2010-12-21 01:50:21 +00:00
parent b907e8a2d4
commit 8d0963f72c
2 changed files with 85 additions and 1 deletions
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47
lib/CodeGen/SplitKit.cpp
View File

@ -24,6 +24,7 @@
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/GraphWriter.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/Target/TargetMachine.h"
@ -34,6 +35,52 @@ static cl::opt<bool>
AllowSplit("spiller-splits-edges",
cl::desc("Allow critical edge splitting during spilling"));
//===----------------------------------------------------------------------===//
// Edge Bundles
//===----------------------------------------------------------------------===//
/// compute - Compute the edge bundles for MF. Bundles depend only on the CFG.
void EdgeBundles::compute(const MachineFunction *mf) {
MF = mf;
EC.clear();
EC.grow(2 * MF->size());
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end(); I != E;
++I) {
const MachineBasicBlock &MBB = *I;
unsigned OutE = 2 * MBB.getNumber() + 1;
// Join the outgoing bundle with the ingoing bundles of all successors.
for (MachineBasicBlock::const_succ_iterator SI = MBB.succ_begin(),
SE = MBB.succ_end(); SI != SE; ++SI)
EC.join(OutE, 2 * (*SI)->getNumber());
}
EC.compress();
}
/// view - Visualize the annotated bipartite CFG with Graphviz.
void EdgeBundles::view() const {
ViewGraph(*this, "EdgeBundles");
}
/// Specialize WriteGraph, the standard implementation won't work.
raw_ostream &llvm::WriteGraph(raw_ostream &O, const EdgeBundles &G,
bool ShortNames,
const std::string &Title) {
const MachineFunction *MF = G.getMachineFunction();
O << "digraph {\n";
for (MachineFunction::const_iterator I = MF->begin(), E = MF->end();
I != E; ++I) {
unsigned BB = I->getNumber();
O << "\t\"BB#" << BB << "\" [ shape=box ]\n"
<< '\t' << G.getBundle(BB, false) << " -> \"BB#" << BB << "\"\n"
<< "\t\"BB#" << BB << "\" -> " << G.getBundle(BB, true) << '\n';
}
O << "}\n";
return O;
}
//===----------------------------------------------------------------------===//
// Split Analysis
//===----------------------------------------------------------------------===//