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#include <cassert>
#include <iostream>
#include <cfg/domtree.h>
#include <wasm.h>
using namespace wasm;
struct BasicBlock {
std::vector<BasicBlock*> in;
void addPred(BasicBlock* pred) { in.push_back(pred); }
};
struct CFG : public std::vector<std::unique_ptr<BasicBlock>> {
BasicBlock* add() {
emplace_back(std::make_unique<BasicBlock>());
return back().get();
}
void connect(BasicBlock* pred, BasicBlock* succ) { succ->addPred(pred); }
};
int main() {
// An empty CFG.
{
CFG cfg;
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.empty());
}
// An CFG with just an entry.
{
CFG cfg;
cfg.add();
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 1);
assert(domTree.iDoms[0] == Index(-1)); // the entry has no parent.
}
// entry -> a.
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
cfg.connect(entry, a);
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 2);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == 0); // a is dominated by the entry.
}
// entry and a non-connected (unreachable) block.
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 2);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == Index(-1)); // unreachables have no parent.
}
// entry -> a -> b -> c.
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
auto* b = cfg.add();
auto* c = cfg.add();
cfg.connect(entry, a);
cfg.connect(a, b);
cfg.connect(b, c);
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 4);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == 0);
assert(domTree.iDoms[2] == 1);
assert(domTree.iDoms[3] == 2);
}
// An if:
// b
// / \
// entry -> a d
// \ /
// c
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
auto* b = cfg.add();
auto* c = cfg.add();
auto* d = cfg.add();
cfg.connect(entry, a);
cfg.connect(a, b);
cfg.connect(a, c);
cfg.connect(b, d);
cfg.connect(c, d);
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 5);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == 0); // a
assert(domTree.iDoms[2] == 1); // b
assert(domTree.iDoms[3] == 1); // c
assert(domTree.iDoms[4] == 1); // d is also dominated by a.
}
// A loop:
//
// entry -> a -> b -> c -> d
// ^ |
// | |
// \---------/
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
auto* b = cfg.add();
auto* c = cfg.add();
auto* d = cfg.add();
cfg.connect(entry, a);
cfg.connect(a, b);
cfg.connect(b, c);
cfg.connect(c, d);
cfg.connect(d, b);
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 5);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == 0); // a
assert(domTree.iDoms[2] == 1); // b, the loop entry, is dominated by a
assert(domTree.iDoms[3] == 2); // c, the loop "middle", is dominated by b
assert(domTree.iDoms[4] == 3); // d, the loop "end", is dominated by c
}
// Subsequent blocks after an unreachable one.
//
// entry a -> b
//
// (a is unreachable, and b is reached by a, but in unreachable code)
{
CFG cfg;
auto* entry = cfg.add();
auto* a = cfg.add();
auto* b = cfg.add();
cfg.connect(a, b);
DomTree<BasicBlock> domTree(cfg);
assert(domTree.iDoms.size() == 3);
assert(domTree.iDoms[0] == Index(-1));
assert(domTree.iDoms[1] == Index(-1)); // a
assert(domTree.iDoms[2] == Index(-1)); // b
}
std::cout << "success.\n";
}
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