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llvm/unittests/Analysis/LazyCallGraphTest.cpp
Chandler Carruth a59e5882a0 [LCG] Construct an actual call graph with call-edge SCCs nested inside 
reference-edge SCCs.

This essentially builds a more normal call graph as a subgraph of the
"reference graph" that was the old model. This allows both to exist and
the different use cases to use the aspect which addresses their needs.
Specifically, the pass manager and other *ordering* constrained logic
can use the reference graph to achieve conservative order of visit,
while analyses reasoning about attributes and other properties derived
from reachability can reason about the direct call graph.

Note that this isn't necessarily complete: it doesn't model edges to
declarations or indirect calls. Those can be found by scanning the
instructions of the function if desirable, and in fact every user
currently does this in order to handle things like calls to instrinsics.
If useful, we could consider caching this information in the call graph
to save the instruction scans, but currently that doesn't seem to be
important.

An important realization for why the representation chosen here works is
that the call graph is a formal subset of the reference graph and thus
both can live within the same data structure. All SCCs of the call graph
are necessarily contained within an SCC of the reference graph, etc.

The design is to build 'RefSCC's to model SCCs of the reference graph,
and then within them more literal SCCs for the call graph.

The formation of actual call edge SCCs is not done lazily, unlike
reference edge 'RefSCC's. Instead, once a reference SCC is formed, it
directly builds the call SCCs within it and stores them in a post-order
sequence. This is used to provide a consistent platform for mutation and
update of the graph. The post-order also allows for very efficient
updates in common cases by bounding the number of nodes (and thus edges)
considered.

There is considerable common code that I'm still looking for the best
way to factor out between the various DFS implementations here. So far,
my attempts have made the code harder to read and understand despite
reducing the duplication, which seems a poor tradeoff. I've not given up
on figuring out the right way to do this, but I wanted to wait until
I at least had the system working and tested to continue attempting to
factor it differently.

This also requires introducing several new algorithms in order to handle
all of the incremental update scenarios for the more complex structure
involving two edge colorings. I've tried to comment the algorithms
sufficiently to make it clear how this is expected to work, but they may
still need more extensive documentation.

I know that there are some changes which are not strictly necessarily
coupled here. The process of developing this started out with a very
focused set of changes for the new structure of the graph and
algorithms, but subsequent changes to bring the APIs and code into
consistent and understandable patterns also ended up touching on other
aspects. There was no good way to separate these out without causing
*massive* merge conflicts. Ultimately, to a large degree this is
a rewrite of most of the core algorithms in the LCG class and so I don't
think it really matters much.

Many thanks to the careful review by Sanjoy Das!

Differential Revision: http://reviews.llvm.org/D16802

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@261040 91177308-0d34-0410-b5e6-96231b3b80d8
2016-02-17 00:18:16 +00:00

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//===- LazyCallGraphTest.cpp - Unit tests for the lazy CG analysis --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LazyCallGraph.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
#include <memory>
using namespace llvm;
namespace {
std::unique_ptr<Module> parseAssembly(const char *Assembly) {
SMDiagnostic Error;
std::unique_ptr<Module> M =
parseAssemblyString(Assembly, Error, getGlobalContext());
std::string ErrMsg;
raw_string_ostream OS(ErrMsg);
Error.print("", OS);
// A failure here means that the test itself is buggy.
if (!M)
report_fatal_error(OS.str().c_str());
return M;
}
/*
IR forming a call graph with a diamond of triangle-shaped SCCs:
d1
/ \
d3--d2
/ \
b1 c1
/ \ / \
b3--b2 c3--c2
\ /
a1
/ \
a3--a2
All call edges go up between SCCs, and clockwise around the SCC.
*/
static const char DiamondOfTriangles[] =
"define void @a1() {\n"
"entry:\n"
" call void @a2()\n"
" call void @b2()\n"
" call void @c3()\n"
" ret void\n"
"}\n"
"define void @a2() {\n"
"entry:\n"
" call void @a3()\n"
" ret void\n"
"}\n"
"define void @a3() {\n"
"entry:\n"
" call void @a1()\n"
" ret void\n"
"}\n"
"define void @b1() {\n"
"entry:\n"
" call void @b2()\n"
" call void @d3()\n"
" ret void\n"
"}\n"
"define void @b2() {\n"
"entry:\n"
" call void @b3()\n"
" ret void\n"
"}\n"
"define void @b3() {\n"
"entry:\n"
" call void @b1()\n"
" ret void\n"
"}\n"
"define void @c1() {\n"
"entry:\n"
" call void @c2()\n"
" call void @d2()\n"
" ret void\n"
"}\n"
"define void @c2() {\n"
"entry:\n"
" call void @c3()\n"
" ret void\n"
"}\n"
"define void @c3() {\n"
"entry:\n"
" call void @c1()\n"
" ret void\n"
"}\n"
"define void @d1() {\n"
"entry:\n"
" call void @d2()\n"
" ret void\n"
"}\n"
"define void @d2() {\n"
"entry:\n"
" call void @d3()\n"
" ret void\n"
"}\n"
"define void @d3() {\n"
"entry:\n"
" call void @d1()\n"
" ret void\n"
"}\n";
TEST(LazyCallGraphTest, BasicGraphFormation) {
std::unique_ptr<Module> M = parseAssembly(DiamondOfTriangles);
LazyCallGraph CG(*M);
// The order of the entry nodes should be stable w.r.t. the source order of
// the IR, and everything in our module is an entry node, so just directly
// build variables for each node.
auto I = CG.begin();
LazyCallGraph::Node &A1 = (I++)->getNode(CG);
EXPECT_EQ("a1", A1.getFunction().getName());
LazyCallGraph::Node &A2 = (I++)->getNode(CG);
EXPECT_EQ("a2", A2.getFunction().getName());
LazyCallGraph::Node &A3 = (I++)->getNode(CG);
EXPECT_EQ("a3", A3.getFunction().getName());
LazyCallGraph::Node &B1 = (I++)->getNode(CG);
EXPECT_EQ("b1", B1.getFunction().getName());
LazyCallGraph::Node &B2 = (I++)->getNode(CG);
EXPECT_EQ("b2", B2.getFunction().getName());
LazyCallGraph::Node &B3 = (I++)->getNode(CG);
EXPECT_EQ("b3", B3.getFunction().getName());
LazyCallGraph::Node &C1 = (I++)->getNode(CG);
EXPECT_EQ("c1", C1.getFunction().getName());
LazyCallGraph::Node &C2 = (I++)->getNode(CG);
EXPECT_EQ("c2", C2.getFunction().getName());
LazyCallGraph::Node &C3 = (I++)->getNode(CG);
EXPECT_EQ("c3", C3.getFunction().getName());
LazyCallGraph::Node &D1 = (I++)->getNode(CG);
EXPECT_EQ("d1", D1.getFunction().getName());
LazyCallGraph::Node &D2 = (I++)->getNode(CG);
EXPECT_EQ("d2", D2.getFunction().getName());
LazyCallGraph::Node &D3 = (I++)->getNode(CG);
EXPECT_EQ("d3", D3.getFunction().getName());
EXPECT_EQ(CG.end(), I);
// Build vectors and sort them for the rest of the assertions to make them
// independent of order.
std::vector<std::string> Nodes;
for (LazyCallGraph::Edge &E : A1)
Nodes.push_back(E.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ("a2", Nodes[0]);
EXPECT_EQ("b2", Nodes[1]);
EXPECT_EQ("c3", Nodes[2]);
Nodes.clear();
EXPECT_EQ(A2.end(), std::next(A2.begin()));
EXPECT_EQ("a3", A2.begin()->getFunction().getName());
EXPECT_EQ(A3.end(), std::next(A3.begin()));
EXPECT_EQ("a1", A3.begin()->getFunction().getName());
for (LazyCallGraph::Edge &E : B1)
Nodes.push_back(E.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ("b2", Nodes[0]);
EXPECT_EQ("d3", Nodes[1]);
Nodes.clear();
EXPECT_EQ(B2.end(), std::next(B2.begin()));
EXPECT_EQ("b3", B2.begin()->getFunction().getName());
EXPECT_EQ(B3.end(), std::next(B3.begin()));
EXPECT_EQ("b1", B3.begin()->getFunction().getName());
for (LazyCallGraph::Edge &E : C1)
Nodes.push_back(E.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ("c2", Nodes[0]);
EXPECT_EQ("d2", Nodes[1]);
Nodes.clear();
EXPECT_EQ(C2.end(), std::next(C2.begin()));
EXPECT_EQ("c3", C2.begin()->getFunction().getName());
EXPECT_EQ(C3.end(), std::next(C3.begin()));
EXPECT_EQ("c1", C3.begin()->getFunction().getName());
EXPECT_EQ(D1.end(), std::next(D1.begin()));
EXPECT_EQ("d2", D1.begin()->getFunction().getName());
EXPECT_EQ(D2.end(), std::next(D2.begin()));
EXPECT_EQ("d3", D2.begin()->getFunction().getName());
EXPECT_EQ(D3.end(), std::next(D3.begin()));
EXPECT_EQ("d1", D3.begin()->getFunction().getName());
// Now lets look at the RefSCCs and SCCs.
auto J = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &D = *J++;
ASSERT_EQ(1, D.size());
for (LazyCallGraph::Node &N : *D.begin())
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("d1", Nodes[0]);
EXPECT_EQ("d2", Nodes[1]);
EXPECT_EQ("d3", Nodes[2]);
Nodes.clear();
EXPECT_FALSE(D.isParentOf(D));
EXPECT_FALSE(D.isChildOf(D));
EXPECT_FALSE(D.isAncestorOf(D));
EXPECT_FALSE(D.isDescendantOf(D));
LazyCallGraph::RefSCC &C = *J++;
ASSERT_EQ(1, C.size());
for (LazyCallGraph::Node &N : *C.begin())
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("c1", Nodes[0]);
EXPECT_EQ("c2", Nodes[1]);
EXPECT_EQ("c3", Nodes[2]);
Nodes.clear();
EXPECT_TRUE(C.isParentOf(D));
EXPECT_FALSE(C.isChildOf(D));
EXPECT_TRUE(C.isAncestorOf(D));
EXPECT_FALSE(C.isDescendantOf(D));
LazyCallGraph::RefSCC &B = *J++;
ASSERT_EQ(1, B.size());
for (LazyCallGraph::Node &N : *B.begin())
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("b1", Nodes[0]);
EXPECT_EQ("b2", Nodes[1]);
EXPECT_EQ("b3", Nodes[2]);
Nodes.clear();
EXPECT_TRUE(B.isParentOf(D));
EXPECT_FALSE(B.isChildOf(D));
EXPECT_TRUE(B.isAncestorOf(D));
EXPECT_FALSE(B.isDescendantOf(D));
EXPECT_FALSE(B.isAncestorOf(C));
EXPECT_FALSE(C.isAncestorOf(B));
LazyCallGraph::RefSCC &A = *J++;
ASSERT_EQ(1, A.size());
for (LazyCallGraph::Node &N : *A.begin())
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("a1", Nodes[0]);
EXPECT_EQ("a2", Nodes[1]);
EXPECT_EQ("a3", Nodes[2]);
Nodes.clear();
EXPECT_TRUE(A.isParentOf(B));
EXPECT_TRUE(A.isParentOf(C));
EXPECT_FALSE(A.isParentOf(D));
EXPECT_TRUE(A.isAncestorOf(B));
EXPECT_TRUE(A.isAncestorOf(C));
EXPECT_TRUE(A.isAncestorOf(D));
EXPECT_EQ(CG.postorder_ref_scc_end(), J);
}
static Function &lookupFunction(Module &M, StringRef Name) {
for (Function &F : M)
if (F.getName() == Name)
return F;
report_fatal_error("Couldn't find function!");
}
TEST(LazyCallGraphTest, BasicGraphMutation) {
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b()\n"
" call void @c()\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
LazyCallGraph::Node &A = CG.get(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = CG.get(lookupFunction(*M, "b"));
EXPECT_EQ(2, std::distance(A.begin(), A.end()));
EXPECT_EQ(0, std::distance(B.begin(), B.end()));
CG.insertEdge(B, lookupFunction(*M, "c"), LazyCallGraph::Edge::Call);
EXPECT_EQ(1, std::distance(B.begin(), B.end()));
LazyCallGraph::Node &C = B.begin()->getNode(CG);
EXPECT_EQ(0, std::distance(C.begin(), C.end()));
CG.insertEdge(C, B.getFunction(), LazyCallGraph::Edge::Call);
EXPECT_EQ(1, std::distance(C.begin(), C.end()));
EXPECT_EQ(&B, C.begin()->getNode());
CG.insertEdge(C, C.getFunction(), LazyCallGraph::Edge::Call);
EXPECT_EQ(2, std::distance(C.begin(), C.end()));
EXPECT_EQ(&B, C.begin()->getNode());
EXPECT_EQ(&C, std::next(C.begin())->getNode());
CG.removeEdge(C, B.getFunction());
EXPECT_EQ(1, std::distance(C.begin(), C.end()));
EXPECT_EQ(&C, C.begin()->getNode());
CG.removeEdge(C, C.getFunction());
EXPECT_EQ(0, std::distance(C.begin(), C.end()));
CG.removeEdge(B, C.getFunction());
EXPECT_EQ(0, std::distance(B.begin(), B.end()));
}
TEST(LazyCallGraphTest, InnerSCCFormation) {
std::unique_ptr<Module> M = parseAssembly(DiamondOfTriangles);
LazyCallGraph CG(*M);
// Now mutate the graph to connect every node into a single RefSCC to ensure
// that our inner SCC formation handles the rest.
CG.insertEdge(lookupFunction(*M, "d1"), lookupFunction(*M, "a1"),
LazyCallGraph::Edge::Ref);
// Build vectors and sort them for the rest of the assertions to make them
// independent of order.
std::vector<std::string> Nodes;
// We should build a single RefSCC for the entire graph.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
// Now walk the four SCCs which should be in post-order.
auto J = RC.begin();
LazyCallGraph::SCC &D = *J++;
for (LazyCallGraph::Node &N : D)
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("d1", Nodes[0]);
EXPECT_EQ("d2", Nodes[1]);
EXPECT_EQ("d3", Nodes[2]);
Nodes.clear();
LazyCallGraph::SCC &B = *J++;
for (LazyCallGraph::Node &N : B)
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("b1", Nodes[0]);
EXPECT_EQ("b2", Nodes[1]);
EXPECT_EQ("b3", Nodes[2]);
Nodes.clear();
LazyCallGraph::SCC &C = *J++;
for (LazyCallGraph::Node &N : C)
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("c1", Nodes[0]);
EXPECT_EQ("c2", Nodes[1]);
EXPECT_EQ("c3", Nodes[2]);
Nodes.clear();
LazyCallGraph::SCC &A = *J++;
for (LazyCallGraph::Node &N : A)
Nodes.push_back(N.getFunction().getName());
std::sort(Nodes.begin(), Nodes.end());
EXPECT_EQ(3u, Nodes.size());
EXPECT_EQ("a1", Nodes[0]);
EXPECT_EQ("a2", Nodes[1]);
EXPECT_EQ("a3", Nodes[2]);
Nodes.clear();
EXPECT_EQ(RC.end(), J);
}
TEST(LazyCallGraphTest, MultiArmSCC) {
// Two interlocking cycles. The really useful thing about this SCC is that it
// will require Tarjan's DFS to backtrack and finish processing all of the
// children of each node in the SCC. Since this involves call edges, both
// Tarjan implementations will have to successfully navigate the structure.
std::unique_ptr<Module> M = parseAssembly(
"define void @f1() {\n"
"entry:\n"
" call void @f2()\n"
" call void @f4()\n"
" ret void\n"
"}\n"
"define void @f2() {\n"
"entry:\n"
" call void @f3()\n"
" ret void\n"
"}\n"
"define void @f3() {\n"
"entry:\n"
" call void @f1()\n"
" ret void\n"
"}\n"
"define void @f4() {\n"
"entry:\n"
" call void @f5()\n"
" ret void\n"
"}\n"
"define void @f5() {\n"
"entry:\n"
" call void @f1()\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &N1 = *CG.lookup(lookupFunction(*M, "f1"));
LazyCallGraph::Node &N2 = *CG.lookup(lookupFunction(*M, "f2"));
LazyCallGraph::Node &N3 = *CG.lookup(lookupFunction(*M, "f3"));
LazyCallGraph::Node &N4 = *CG.lookup(lookupFunction(*M, "f4"));
LazyCallGraph::Node &N5 = *CG.lookup(lookupFunction(*M, "f4"));
EXPECT_EQ(&RC, CG.lookupRefSCC(N1));
EXPECT_EQ(&RC, CG.lookupRefSCC(N2));
EXPECT_EQ(&RC, CG.lookupRefSCC(N3));
EXPECT_EQ(&RC, CG.lookupRefSCC(N4));
EXPECT_EQ(&RC, CG.lookupRefSCC(N5));
ASSERT_EQ(1, RC.size());
LazyCallGraph::SCC &C = *RC.begin();
EXPECT_EQ(&C, CG.lookupSCC(N1));
EXPECT_EQ(&C, CG.lookupSCC(N2));
EXPECT_EQ(&C, CG.lookupSCC(N3));
EXPECT_EQ(&C, CG.lookupSCC(N4));
EXPECT_EQ(&C, CG.lookupSCC(N5));
}
TEST(LazyCallGraphTest, OutgoingEdgeMutation) {
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b()\n"
" call void @c()\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @d() {\n"
"entry:\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
for (LazyCallGraph::RefSCC &RC : CG.postorder_ref_sccs())
(void)RC;
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
LazyCallGraph::Node &D = *CG.lookup(lookupFunction(*M, "d"));
LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
LazyCallGraph::SCC &BC = *CG.lookupSCC(B);
LazyCallGraph::SCC &CC = *CG.lookupSCC(C);
LazyCallGraph::SCC &DC = *CG.lookupSCC(D);
LazyCallGraph::RefSCC &ARC = *CG.lookupRefSCC(A);
LazyCallGraph::RefSCC &BRC = *CG.lookupRefSCC(B);
LazyCallGraph::RefSCC &CRC = *CG.lookupRefSCC(C);
LazyCallGraph::RefSCC &DRC = *CG.lookupRefSCC(D);
EXPECT_TRUE(ARC.isParentOf(BRC));
EXPECT_TRUE(ARC.isParentOf(CRC));
EXPECT_FALSE(ARC.isParentOf(DRC));
EXPECT_TRUE(ARC.isAncestorOf(DRC));
EXPECT_FALSE(DRC.isChildOf(ARC));
EXPECT_TRUE(DRC.isDescendantOf(ARC));
EXPECT_TRUE(DRC.isChildOf(BRC));
EXPECT_TRUE(DRC.isChildOf(CRC));
EXPECT_EQ(2, std::distance(A.begin(), A.end()));
ARC.insertOutgoingEdge(A, D, LazyCallGraph::Edge::Call);
EXPECT_EQ(3, std::distance(A.begin(), A.end()));
const LazyCallGraph::Edge &NewE = A[D];
EXPECT_TRUE(NewE);
EXPECT_TRUE(NewE.isCall());
EXPECT_EQ(&D, NewE.getNode());
// Only the parent and child tests sholud have changed. The rest of the graph
// remains the same.
EXPECT_TRUE(ARC.isParentOf(DRC));
EXPECT_TRUE(ARC.isAncestorOf(DRC));
EXPECT_TRUE(DRC.isChildOf(ARC));
EXPECT_TRUE(DRC.isDescendantOf(ARC));
EXPECT_EQ(&AC, CG.lookupSCC(A));
EXPECT_EQ(&BC, CG.lookupSCC(B));
EXPECT_EQ(&CC, CG.lookupSCC(C));
EXPECT_EQ(&DC, CG.lookupSCC(D));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C));
EXPECT_EQ(&DRC, CG.lookupRefSCC(D));
ARC.switchOutgoingEdgeToRef(A, D);
EXPECT_FALSE(NewE.isCall());
// Verify the graph remains the same.
EXPECT_TRUE(ARC.isParentOf(DRC));
EXPECT_TRUE(ARC.isAncestorOf(DRC));
EXPECT_TRUE(DRC.isChildOf(ARC));
EXPECT_TRUE(DRC.isDescendantOf(ARC));
EXPECT_EQ(&AC, CG.lookupSCC(A));
EXPECT_EQ(&BC, CG.lookupSCC(B));
EXPECT_EQ(&CC, CG.lookupSCC(C));
EXPECT_EQ(&DC, CG.lookupSCC(D));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C));
EXPECT_EQ(&DRC, CG.lookupRefSCC(D));
ARC.switchOutgoingEdgeToCall(A, D);
EXPECT_TRUE(NewE.isCall());
// Verify the graph remains the same.
EXPECT_TRUE(ARC.isParentOf(DRC));
EXPECT_TRUE(ARC.isAncestorOf(DRC));
EXPECT_TRUE(DRC.isChildOf(ARC));
EXPECT_TRUE(DRC.isDescendantOf(ARC));
EXPECT_EQ(&AC, CG.lookupSCC(A));
EXPECT_EQ(&BC, CG.lookupSCC(B));
EXPECT_EQ(&CC, CG.lookupSCC(C));
EXPECT_EQ(&DC, CG.lookupSCC(D));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C));
EXPECT_EQ(&DRC, CG.lookupRefSCC(D));
ARC.removeOutgoingEdge(A, D);
EXPECT_EQ(2, std::distance(A.begin(), A.end()));
// Now the parent and child tests fail again but the rest remains the same.
EXPECT_FALSE(ARC.isParentOf(DRC));
EXPECT_TRUE(ARC.isAncestorOf(DRC));
EXPECT_FALSE(DRC.isChildOf(ARC));
EXPECT_TRUE(DRC.isDescendantOf(ARC));
EXPECT_EQ(&AC, CG.lookupSCC(A));
EXPECT_EQ(&BC, CG.lookupSCC(B));
EXPECT_EQ(&CC, CG.lookupSCC(C));
EXPECT_EQ(&DC, CG.lookupSCC(D));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C));
EXPECT_EQ(&DRC, CG.lookupRefSCC(D));
}
TEST(LazyCallGraphTest, IncomingEdgeInsertion) {
// We want to ensure we can add edges even across complex diamond graphs, so
// we use the diamond of triangles graph defined above. The ascii diagram is
// repeated here for easy reference.
//
// d1 |
// / \ |
// d3--d2 |
// / \ |
// b1 c1 |
// / \ / \ |
// b3--b2 c3--c2 |
// \ / |
// a1 |
// / \ |
// a3--a2 |
//
std::unique_ptr<Module> M = parseAssembly(DiamondOfTriangles);
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
for (LazyCallGraph::RefSCC &RC : CG.postorder_ref_sccs())
(void)RC;
LazyCallGraph::Node &A1 = *CG.lookup(lookupFunction(*M, "a1"));
LazyCallGraph::Node &A2 = *CG.lookup(lookupFunction(*M, "a2"));
LazyCallGraph::Node &A3 = *CG.lookup(lookupFunction(*M, "a3"));
LazyCallGraph::Node &B1 = *CG.lookup(lookupFunction(*M, "b1"));
LazyCallGraph::Node &B2 = *CG.lookup(lookupFunction(*M, "b2"));
LazyCallGraph::Node &B3 = *CG.lookup(lookupFunction(*M, "b3"));
LazyCallGraph::Node &C1 = *CG.lookup(lookupFunction(*M, "c1"));
LazyCallGraph::Node &C2 = *CG.lookup(lookupFunction(*M, "c2"));
LazyCallGraph::Node &C3 = *CG.lookup(lookupFunction(*M, "c3"));
LazyCallGraph::Node &D1 = *CG.lookup(lookupFunction(*M, "d1"));
LazyCallGraph::Node &D2 = *CG.lookup(lookupFunction(*M, "d2"));
LazyCallGraph::Node &D3 = *CG.lookup(lookupFunction(*M, "d3"));
LazyCallGraph::RefSCC &ARC = *CG.lookupRefSCC(A1);
LazyCallGraph::RefSCC &BRC = *CG.lookupRefSCC(B1);
LazyCallGraph::RefSCC &CRC = *CG.lookupRefSCC(C1);
LazyCallGraph::RefSCC &DRC = *CG.lookupRefSCC(D1);
ASSERT_EQ(&ARC, CG.lookupRefSCC(A2));
ASSERT_EQ(&ARC, CG.lookupRefSCC(A3));
ASSERT_EQ(&BRC, CG.lookupRefSCC(B2));
ASSERT_EQ(&BRC, CG.lookupRefSCC(B3));
ASSERT_EQ(&CRC, CG.lookupRefSCC(C2));
ASSERT_EQ(&CRC, CG.lookupRefSCC(C3));
ASSERT_EQ(&DRC, CG.lookupRefSCC(D2));
ASSERT_EQ(&DRC, CG.lookupRefSCC(D3));
ASSERT_EQ(1, std::distance(D2.begin(), D2.end()));
// Add an edge to make the graph:
//
// d1 |
// / \ |
// d3--d2---. |
// / \ | |
// b1 c1 | |
// / \ / \ / |
// b3--b2 c3--c2 |
// \ / |
// a1 |
// / \ |
// a3--a2 |
auto MergedRCs = CRC.insertIncomingRefEdge(D2, C2);
// Make sure we connected the nodes.
for (LazyCallGraph::Edge E : D2) {
if (E.getNode() == &D3)
continue;
EXPECT_EQ(&C2, E.getNode());
}
// And marked the D ref-SCC as no longer valid.
EXPECT_EQ(1u, MergedRCs.size());
EXPECT_EQ(&DRC, MergedRCs[0]);
// Make sure we have the correct nodes in the SCC sets.
EXPECT_EQ(&ARC, CG.lookupRefSCC(A1));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A2));
EXPECT_EQ(&ARC, CG.lookupRefSCC(A3));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B1));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B2));
EXPECT_EQ(&BRC, CG.lookupRefSCC(B3));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C1));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C2));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C3));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D1));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D2));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D3));
// And that ancestry tests have been updated.
EXPECT_TRUE(ARC.isParentOf(CRC));
EXPECT_TRUE(BRC.isParentOf(CRC));
}
TEST(LazyCallGraphTest, IncomingEdgeInsertionMidTraversal) {
// This is the same fundamental test as the previous, but we perform it
// having only partially walked the RefSCCs of the graph.
std::unique_ptr<Module> M = parseAssembly(DiamondOfTriangles);
LazyCallGraph CG(*M);
// Walk the RefSCCs until we find the one containing 'c1'.
auto I = CG.postorder_ref_scc_begin(), E = CG.postorder_ref_scc_end();
ASSERT_NE(I, E);
LazyCallGraph::RefSCC &DRC = *I;
ASSERT_NE(&DRC, nullptr);
++I;
ASSERT_NE(I, E);
LazyCallGraph::RefSCC &CRC = *I;
ASSERT_NE(&CRC, nullptr);
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "a1")));
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "a2")));
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "a3")));
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "b1")));
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "b2")));
ASSERT_EQ(nullptr, CG.lookup(lookupFunction(*M, "b3")));
LazyCallGraph::Node &C1 = *CG.lookup(lookupFunction(*M, "c1"));
LazyCallGraph::Node &C2 = *CG.lookup(lookupFunction(*M, "c2"));
LazyCallGraph::Node &C3 = *CG.lookup(lookupFunction(*M, "c3"));
LazyCallGraph::Node &D1 = *CG.lookup(lookupFunction(*M, "d1"));
LazyCallGraph::Node &D2 = *CG.lookup(lookupFunction(*M, "d2"));
LazyCallGraph::Node &D3 = *CG.lookup(lookupFunction(*M, "d3"));
ASSERT_EQ(&CRC, CG.lookupRefSCC(C1));
ASSERT_EQ(&CRC, CG.lookupRefSCC(C2));
ASSERT_EQ(&CRC, CG.lookupRefSCC(C3));
ASSERT_EQ(&DRC, CG.lookupRefSCC(D1));
ASSERT_EQ(&DRC, CG.lookupRefSCC(D2));
ASSERT_EQ(&DRC, CG.lookupRefSCC(D3));
ASSERT_EQ(1, std::distance(D2.begin(), D2.end()));
auto MergedRCs = CRC.insertIncomingRefEdge(D2, C2);
// Make sure we connected the nodes.
for (LazyCallGraph::Edge E : D2) {
if (E.getNode() == &D3)
continue;
EXPECT_EQ(&C2, E.getNode());
}
// And marked the D ref-SCC as no longer valid.
EXPECT_EQ(1u, MergedRCs.size());
EXPECT_EQ(&DRC, MergedRCs[0]);
// Make sure we have the correct nodes in the RefSCCs.
EXPECT_EQ(&CRC, CG.lookupRefSCC(C1));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C2));
EXPECT_EQ(&CRC, CG.lookupRefSCC(C3));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D1));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D2));
EXPECT_EQ(&CRC, CG.lookupRefSCC(D3));
// Check that we can form the last two RefSCCs now in a coherent way.
++I;
EXPECT_NE(I, E);
LazyCallGraph::RefSCC &BRC = *I;
EXPECT_NE(&BRC, nullptr);
EXPECT_EQ(&BRC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "b1"))));
EXPECT_EQ(&BRC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "b2"))));
EXPECT_EQ(&BRC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "b3"))));
EXPECT_TRUE(BRC.isParentOf(CRC));
++I;
EXPECT_NE(I, E);
LazyCallGraph::RefSCC &ARC = *I;
EXPECT_NE(&ARC, nullptr);
EXPECT_EQ(&ARC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "a1"))));
EXPECT_EQ(&ARC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "a2"))));
EXPECT_EQ(&ARC, CG.lookupRefSCC(*CG.lookup(lookupFunction(*M, "a3"))));
EXPECT_TRUE(ARC.isParentOf(CRC));
++I;
EXPECT_EQ(E, I);
}
TEST(LazyCallGraphTest, InternalEdgeMutation) {
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b()\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" call void @c()\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" call void @a()\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(&RC, CG.lookupRefSCC(B));
EXPECT_EQ(&RC, CG.lookupRefSCC(C));
EXPECT_EQ(1, RC.size());
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(A));
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(B));
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(C));
// Insert an edge from 'a' to 'c'. Nothing changes about the graph.
RC.insertInternalRefEdge(A, C);
EXPECT_EQ(2, std::distance(A.begin(), A.end()));
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(&RC, CG.lookupRefSCC(B));
EXPECT_EQ(&RC, CG.lookupRefSCC(C));
EXPECT_EQ(1, RC.size());
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(A));
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(B));
EXPECT_EQ(&*RC.begin(), CG.lookupSCC(C));
// Switch the call edge from 'b' to 'c' to a ref edge. This will break the
// call cycle and cause us to form more SCCs. The RefSCC will remain the same
// though.
RC.switchInternalEdgeToRef(B, C);
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(&RC, CG.lookupRefSCC(B));
EXPECT_EQ(&RC, CG.lookupRefSCC(C));
auto J = RC.begin();
// The SCCs must be in *post-order* which means successors before
// predecessors. At this point we have call edges from C to A and from A to
// B. The only valid postorder is B, A, C.
EXPECT_EQ(&*J++, CG.lookupSCC(B));
EXPECT_EQ(&*J++, CG.lookupSCC(A));
EXPECT_EQ(&*J++, CG.lookupSCC(C));
EXPECT_EQ(RC.end(), J);
// Test turning the ref edge from A to C into a call edge. This will form an
// SCC out of A and C. Since we previously had a call edge from C to A, the
// C SCC should be preserved and have A merged into it while the A SCC should
// be invalidated.
LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
LazyCallGraph::SCC &CC = *CG.lookupSCC(C);
auto InvalidatedSCCs = RC.switchInternalEdgeToCall(A, C);
ASSERT_EQ(1u, InvalidatedSCCs.size());
EXPECT_EQ(&AC, InvalidatedSCCs[0]);
EXPECT_EQ(2, CC.size());
EXPECT_EQ(&CC, CG.lookupSCC(A));
EXPECT_EQ(&CC, CG.lookupSCC(C));
J = RC.begin();
EXPECT_EQ(&*J++, CG.lookupSCC(B));
EXPECT_EQ(&*J++, CG.lookupSCC(C));
EXPECT_EQ(RC.end(), J);
}
TEST(LazyCallGraphTest, InternalEdgeRemoval) {
// A nice fully connected (including self-edges) RefSCC.
std::unique_ptr<Module> M = parseAssembly(
"define void @a(i8** %ptr) {\n"
"entry:\n"
" store i8* bitcast (void(i8**)* @a to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @b to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @c to i8*), i8** %ptr\n"
" ret void\n"
"}\n"
"define void @b(i8** %ptr) {\n"
"entry:\n"
" store i8* bitcast (void(i8**)* @a to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @b to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @c to i8*), i8** %ptr\n"
" ret void\n"
"}\n"
"define void @c(i8** %ptr) {\n"
"entry:\n"
" store i8* bitcast (void(i8**)* @a to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @b to i8*), i8** %ptr\n"
" store i8* bitcast (void(i8**)* @c to i8*), i8** %ptr\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(&RC, CG.lookupRefSCC(B));
EXPECT_EQ(&RC, CG.lookupRefSCC(C));
// Remove the edge from b -> a, which should leave the 3 functions still in
// a single connected component because of a -> b -> c -> a.
SmallVector<LazyCallGraph::RefSCC *, 1> NewRCs =
RC.removeInternalRefEdge(B, A);
EXPECT_EQ(0u, NewRCs.size());
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(&RC, CG.lookupRefSCC(B));
EXPECT_EQ(&RC, CG.lookupRefSCC(C));
// Remove the edge from c -> a, which should leave 'a' in the original RefSCC
// and form a new RefSCC for 'b' and 'c'.
NewRCs = RC.removeInternalRefEdge(C, A);
EXPECT_EQ(1u, NewRCs.size());
EXPECT_EQ(&RC, CG.lookupRefSCC(A));
EXPECT_EQ(1, std::distance(RC.begin(), RC.end()));
LazyCallGraph::RefSCC *RC2 = CG.lookupRefSCC(B);
EXPECT_EQ(RC2, CG.lookupRefSCC(C));
EXPECT_EQ(RC2, NewRCs[0]);
}
TEST(LazyCallGraphTest, InternalCallEdgeToRef) {
// A nice fully connected (including self-edges) SCC (and RefSCC)
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @a()\n"
" call void @b()\n"
" call void @c()\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" call void @a()\n"
" call void @b()\n"
" call void @c()\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" call void @a()\n"
" call void @b()\n"
" call void @c()\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
EXPECT_EQ(1, RC.size());
LazyCallGraph::SCC &CallC = *RC.begin();
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
EXPECT_EQ(&CallC, CG.lookupSCC(A));
EXPECT_EQ(&CallC, CG.lookupSCC(B));
EXPECT_EQ(&CallC, CG.lookupSCC(C));
// Remove the call edge from b -> a to a ref edge, which should leave the
// 3 functions still in a single connected component because of a -> b ->
// c -> a.
RC.switchInternalEdgeToRef(B, A);
EXPECT_EQ(1, RC.size());
EXPECT_EQ(&CallC, CG.lookupSCC(A));
EXPECT_EQ(&CallC, CG.lookupSCC(B));
EXPECT_EQ(&CallC, CG.lookupSCC(C));
// Remove the edge from c -> a, which should leave 'a' in the original SCC
// and form a new SCC for 'b' and 'c'.
RC.switchInternalEdgeToRef(C, A);
EXPECT_EQ(2, RC.size());
EXPECT_EQ(&CallC, CG.lookupSCC(A));
LazyCallGraph::SCC &BCallC = *CG.lookupSCC(B);
EXPECT_NE(&BCallC, &CallC);
EXPECT_EQ(&BCallC, CG.lookupSCC(C));
auto J = RC.find(CallC);
EXPECT_EQ(&CallC, &*J);
--J;
EXPECT_EQ(&BCallC, &*J);
EXPECT_EQ(RC.begin(), J);
// Remove the edge from c -> b, which should leave 'b' in the original SCC
// and form a new SCC for 'c'. It shouldn't change 'a's SCC.
RC.switchInternalEdgeToRef(C, B);
EXPECT_EQ(3, RC.size());
EXPECT_EQ(&CallC, CG.lookupSCC(A));
EXPECT_EQ(&BCallC, CG.lookupSCC(B));
LazyCallGraph::SCC &CCallC = *CG.lookupSCC(C);
EXPECT_NE(&CCallC, &CallC);
EXPECT_NE(&CCallC, &BCallC);
J = RC.find(CallC);
EXPECT_EQ(&CallC, &*J);
--J;
EXPECT_EQ(&BCallC, &*J);
--J;
EXPECT_EQ(&CCallC, &*J);
EXPECT_EQ(RC.begin(), J);
}
TEST(LazyCallGraphTest, InternalRefEdgeToCall) {
// Basic tests for making a ref edge a call. This hits the basics of the
// process only.
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b()\n"
" call void @c()\n"
" store void()* @d, void()** undef\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" store void()* @c, void()** undef\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" store void()* @b, void()** undef\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @d() {\n"
"entry:\n"
" store void()* @a, void()** undef\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
LazyCallGraph::Node &D = *CG.lookup(lookupFunction(*M, "d"));
LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
LazyCallGraph::SCC &BC = *CG.lookupSCC(B);
LazyCallGraph::SCC &CC = *CG.lookupSCC(C);
LazyCallGraph::SCC &DC = *CG.lookupSCC(D);
// Check the initial post-order. Note that B and C could be flipped here (and
// in our mutation) without changing the nature of this test.
ASSERT_EQ(4, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&BC, &RC[1]);
EXPECT_EQ(&CC, &RC[2]);
EXPECT_EQ(&AC, &RC[3]);
// Switch the ref edge from A -> D to a call edge. This should have no
// effect as it is already in postorder and no new cycles are formed.
auto MergedCs = RC.switchInternalEdgeToCall(A, D);
EXPECT_EQ(0u, MergedCs.size());
ASSERT_EQ(4, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&BC, &RC[1]);
EXPECT_EQ(&CC, &RC[2]);
EXPECT_EQ(&AC, &RC[3]);
// Switch B -> C to a call edge. This doesn't form any new cycles but does
// require reordering the SCCs.
MergedCs = RC.switchInternalEdgeToCall(B, C);
EXPECT_EQ(0u, MergedCs.size());
ASSERT_EQ(4, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&CC, &RC[1]);
EXPECT_EQ(&BC, &RC[2]);
EXPECT_EQ(&AC, &RC[3]);
// Switch C -> B to a call edge. This forms a cycle and forces merging SCCs.
MergedCs = RC.switchInternalEdgeToCall(C, B);
ASSERT_EQ(1u, MergedCs.size());
EXPECT_EQ(&CC, MergedCs[0]);
ASSERT_EQ(3, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&BC, &RC[1]);
EXPECT_EQ(&AC, &RC[2]);
EXPECT_EQ(2, BC.size());
EXPECT_EQ(&BC, CG.lookupSCC(B));
EXPECT_EQ(&BC, CG.lookupSCC(C));
}
TEST(LazyCallGraphTest, InternalRefEdgeToCallNoCycleInterleaved) {
// Test for having a post-order prior to changing a ref edge to a call edge
// with SCCs connecting to the source and connecting to the target, but not
// connecting to both, interleaved between the source and target. This
// ensures we correctly partition the range rather than simply moving one or
// the other.
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b1()\n"
" call void @c1()\n"
" ret void\n"
"}\n"
"define void @b1() {\n"
"entry:\n"
" call void @c1()\n"
" call void @b2()\n"
" ret void\n"
"}\n"
"define void @c1() {\n"
"entry:\n"
" call void @b2()\n"
" call void @c2()\n"
" ret void\n"
"}\n"
"define void @b2() {\n"
"entry:\n"
" call void @c2()\n"
" call void @b3()\n"
" ret void\n"
"}\n"
"define void @c2() {\n"
"entry:\n"
" call void @b3()\n"
" call void @c3()\n"
" ret void\n"
"}\n"
"define void @b3() {\n"
"entry:\n"
" call void @c3()\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @c3() {\n"
"entry:\n"
" store void()* @b1, void()** undef\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @d() {\n"
"entry:\n"
" store void()* @a, void()** undef\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B1 = *CG.lookup(lookupFunction(*M, "b1"));
LazyCallGraph::Node &B2 = *CG.lookup(lookupFunction(*M, "b2"));
LazyCallGraph::Node &B3 = *CG.lookup(lookupFunction(*M, "b3"));
LazyCallGraph::Node &C1 = *CG.lookup(lookupFunction(*M, "c1"));
LazyCallGraph::Node &C2 = *CG.lookup(lookupFunction(*M, "c2"));
LazyCallGraph::Node &C3 = *CG.lookup(lookupFunction(*M, "c3"));
LazyCallGraph::Node &D = *CG.lookup(lookupFunction(*M, "d"));
LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
LazyCallGraph::SCC &B1C = *CG.lookupSCC(B1);
LazyCallGraph::SCC &B2C = *CG.lookupSCC(B2);
LazyCallGraph::SCC &B3C = *CG.lookupSCC(B3);
LazyCallGraph::SCC &C1C = *CG.lookupSCC(C1);
LazyCallGraph::SCC &C2C = *CG.lookupSCC(C2);
LazyCallGraph::SCC &C3C = *CG.lookupSCC(C3);
LazyCallGraph::SCC &DC = *CG.lookupSCC(D);
// Several call edges are initially present to force a particual post-order.
// Remove them now, leaving an interleaved post-order pattern.
RC.switchInternalEdgeToRef(B3, C3);
RC.switchInternalEdgeToRef(C2, B3);
RC.switchInternalEdgeToRef(B2, C2);
RC.switchInternalEdgeToRef(C1, B2);
RC.switchInternalEdgeToRef(B1, C1);
// Check the initial post-order. We ensure this order with the extra edges
// that are nuked above.
ASSERT_EQ(8, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&C3C, &RC[1]);
EXPECT_EQ(&B3C, &RC[2]);
EXPECT_EQ(&C2C, &RC[3]);
EXPECT_EQ(&B2C, &RC[4]);
EXPECT_EQ(&C1C, &RC[5]);
EXPECT_EQ(&B1C, &RC[6]);
EXPECT_EQ(&AC, &RC[7]);
// Switch C3 -> B1 to a call edge. This doesn't form any new cycles but does
// require reordering the SCCs in the face of tricky internal node
// structures.
auto MergedCs = RC.switchInternalEdgeToCall(C3, B1);
EXPECT_EQ(0u, MergedCs.size());
ASSERT_EQ(8, RC.size());
EXPECT_EQ(&DC, &RC[0]);
EXPECT_EQ(&B3C, &RC[1]);
EXPECT_EQ(&B2C, &RC[2]);
EXPECT_EQ(&B1C, &RC[3]);
EXPECT_EQ(&C3C, &RC[4]);
EXPECT_EQ(&C2C, &RC[5]);
EXPECT_EQ(&C1C, &RC[6]);
EXPECT_EQ(&AC, &RC[7]);
}
TEST(LazyCallGraphTest, InternalRefEdgeToCallBothPartitionAndMerge) {
// Test for having a postorder where between the source and target are all
// three kinds of other SCCs:
// 1) One connected to the target only that have to be shifted below the
// source.
// 2) One connected to the source only that have to be shifted below the
// target.
// 3) One connected to both source and target that has to remain and get
// merged away.
//
// To achieve this we construct a heavily connected graph to force
// a particular post-order. Then we remove the forcing edges and connect
// a cycle.
//
// Diagram for the graph we want on the left and the graph we use to force
// the ordering on the right. Edges ponit down or right.
//
// A | A |
// / \ | / \ |
// B E | B \ |
// |\ | | |\ | |
// | D | | C-D-E |
// | \| | | \| |
// C F | \ F |
// \ / | \ / |
// G | G |
//
// And we form a cycle by connecting F to B.
std::unique_ptr<Module> M = parseAssembly(
"define void @a() {\n"
"entry:\n"
" call void @b()\n"
" call void @e()\n"
" ret void\n"
"}\n"
"define void @b() {\n"
"entry:\n"
" call void @c()\n"
" call void @d()\n"
" ret void\n"
"}\n"
"define void @c() {\n"
"entry:\n"
" call void @d()\n"
" call void @g()\n"
" ret void\n"
"}\n"
"define void @d() {\n"
"entry:\n"
" call void @e()\n"
" call void @f()\n"
" ret void\n"
"}\n"
"define void @e() {\n"
"entry:\n"
" call void @f()\n"
" ret void\n"
"}\n"
"define void @f() {\n"
"entry:\n"
" store void()* @b, void()** undef\n"
" call void @g()\n"
" ret void\n"
"}\n"
"define void @g() {\n"
"entry:\n"
" store void()* @a, void()** undef\n"
" ret void\n"
"}\n");
LazyCallGraph CG(*M);
// Force the graph to be fully expanded.
auto I = CG.postorder_ref_scc_begin();
LazyCallGraph::RefSCC &RC = *I++;
EXPECT_EQ(CG.postorder_ref_scc_end(), I);
LazyCallGraph::Node &A = *CG.lookup(lookupFunction(*M, "a"));
LazyCallGraph::Node &B = *CG.lookup(lookupFunction(*M, "b"));
LazyCallGraph::Node &C = *CG.lookup(lookupFunction(*M, "c"));
LazyCallGraph::Node &D = *CG.lookup(lookupFunction(*M, "d"));
LazyCallGraph::Node &E = *CG.lookup(lookupFunction(*M, "e"));
LazyCallGraph::Node &F = *CG.lookup(lookupFunction(*M, "f"));
LazyCallGraph::Node &G = *CG.lookup(lookupFunction(*M, "g"));
LazyCallGraph::SCC &AC = *CG.lookupSCC(A);
LazyCallGraph::SCC &BC = *CG.lookupSCC(B);
LazyCallGraph::SCC &CC = *CG.lookupSCC(C);
LazyCallGraph::SCC &DC = *CG.lookupSCC(D);
LazyCallGraph::SCC &EC = *CG.lookupSCC(E);
LazyCallGraph::SCC &FC = *CG.lookupSCC(F);
LazyCallGraph::SCC &GC = *CG.lookupSCC(G);
// Remove the extra edges that were used to force a particular post-order.
RC.switchInternalEdgeToRef(C, D);
RC.switchInternalEdgeToRef(D, E);
// Check the initial post-order. We ensure this order with the extra edges
// that are nuked above.
ASSERT_EQ(7, RC.size());
EXPECT_EQ(&GC, &RC[0]);
EXPECT_EQ(&FC, &RC[1]);
EXPECT_EQ(&EC, &RC[2]);
EXPECT_EQ(&DC, &RC[3]);
EXPECT_EQ(&CC, &RC[4]);
EXPECT_EQ(&BC, &RC[5]);
EXPECT_EQ(&AC, &RC[6]);
// Switch F -> B to a call edge. This merges B, D, and F into a single SCC,
// and has to place the C and E SCCs on either side of it:
// A A |
// / \ / \ |
// B E | E |
// |\ | \ / |
// | D | -> B |
// | \| / \ |
// C F C | |
// \ / \ / |
// G G |
auto MergedCs = RC.switchInternalEdgeToCall(F, B);
ASSERT_EQ(2u, MergedCs.size());
EXPECT_EQ(&FC, MergedCs[0]);
EXPECT_EQ(&DC, MergedCs[1]);
EXPECT_EQ(3, BC.size());
// And make sure the postorder was updated.
ASSERT_EQ(5, RC.size());
EXPECT_EQ(&GC, &RC[0]);
EXPECT_EQ(&CC, &RC[1]);
EXPECT_EQ(&BC, &RC[2]);
EXPECT_EQ(&EC, &RC[3]);
EXPECT_EQ(&AC, &RC[4]);
}
}
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