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verify-uselistorder: Move shuffleUseLists() out of lib/IR
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`shuffleUseLists()` is only used in `verify-uselistorder`, so move it
there to avoid bloating other executables.  As a drive-by, update some
of the header docs.

This is part of PR5680.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214592 91177308-0d34-0410-b5e6-96231b3b80d8
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@dexonsmith
dexonsmith committed Aug 1, 2014
1 parent 65225b6 commit b2b0ad4
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Showing 3 changed files with 105 additions and 117 deletions.
11 changes: 3 additions & 8 deletions include/llvm/IR/UseListOrder.h
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
//===- llvm/IR/UseListOrder.h - LLVM Use List Order functions ---*- C++ -*-===//
//===- llvm/IR/UseListOrder.h - LLVM Use List Order -------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
Expand All @@ -7,8 +7,8 @@
//
//===----------------------------------------------------------------------===//
//
// This file has functions to modify the use-list order and to verify that it
// doesn't change after serialization.
// This file has structures and command-line options for preserving use-list
// order.
//
//===----------------------------------------------------------------------===//

Expand Down Expand Up @@ -111,11 +111,6 @@ typedef std::vector<UseListOrder> UseListOrderStack;
bool shouldPreserveBitcodeUseListOrder();
bool shouldPreserveAssemblyUseListOrder();

/// \brief Shuffle all use-lists in a module.
///
/// Adds \c SeedOffset to the default seed for the random number generator.
void shuffleUseLists(Module &M, unsigned SeedOffset = 0);

} // end namespace llvm

#endif
106 changes: 2 additions & 104 deletions lib/IR/UseListOrder.cpp
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Original file line number Diff line number Diff line change
@@ -1,4 +1,4 @@
//===- UseListOrder.cpp - Implement Use List Order functions --------------===//
//===- UseListOrder.cpp - Implement Use List Order ------------------------===//
//
// The LLVM Compiler Infrastructure
//
Expand All @@ -7,22 +7,12 @@
//
//===----------------------------------------------------------------------===//
//
// Implement use list order functions to modify use-list order and verify it
// doesn't change after serialization.
// Implement structures and command-line options for preserving use-list order.
//
//===----------------------------------------------------------------------===//

#include "llvm/IR/UseListOrder.h"

#include "llvm/ADT/DenseSet.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"

#include <random>
#include <vector>

#define DEBUG_TYPE "use-list-order"

using namespace llvm;

Expand All @@ -43,95 +33,3 @@ bool llvm::shouldPreserveBitcodeUseListOrder() {
bool llvm::shouldPreserveAssemblyUseListOrder() {
return PreserveAssemblyUseListOrder;
}

static void shuffleValueUseLists(Value *V, std::minstd_rand0 &Gen,
DenseSet<Value *> &Seen) {
if (!Seen.insert(V).second)
return;

if (auto *C = dyn_cast<Constant>(V))
if (!isa<GlobalValue>(C))
for (Value *Op : C->operands())
shuffleValueUseLists(Op, Gen, Seen);

if (V->use_empty() || std::next(V->use_begin()) == V->use_end())
// Nothing to shuffle for 0 or 1 users.
return;

// Generate random numbers between 10 and 99, which will line up nicely in
// debug output. We're not worried about collisons here.
DEBUG(dbgs() << "V = "; V->dump());
std::uniform_int_distribution<short> Dist(10, 99);
SmallDenseMap<const Use *, short, 16> Order;
auto compareUses =
[&Order](const Use &L, const Use &R) { return Order[&L] < Order[&R]; };
do {
for (const Use &U : V->uses()) {
auto I = Dist(Gen);
Order[&U] = I;
DEBUG(dbgs() << " - order: " << I << ", op = " << U.getOperandNo()
<< ", U = ";
U.getUser()->dump());
}
} while (std::is_sorted(V->use_begin(), V->use_end(), compareUses));

DEBUG(dbgs() << " => shuffle\n");
V->sortUseList(compareUses);

DEBUG({
for (const Use &U : V->uses()) {
dbgs() << " - order: " << Order.lookup(&U)
<< ", op = " << U.getOperandNo() << ", U = ";
U.getUser()->dump();
}
});
}

void llvm::shuffleUseLists(Module &M, unsigned SeedOffset) {
DEBUG(dbgs() << "*** shuffle-use-lists ***\n");
std::minstd_rand0 Gen(std::minstd_rand0::default_seed + SeedOffset);
DenseSet<Value *> Seen;

// Shuffle the use-list of each value that would be serialized to an IR file
// (bitcode or assembly).
auto shuffle = [&](Value *V) { shuffleValueUseLists(V, Gen, Seen); };

// Globals.
for (GlobalVariable &G : M.globals())
shuffle(&G);
for (GlobalAlias &A : M.aliases())
shuffle(&A);
for (Function &F : M)
shuffle(&F);

// Constants used by globals.
for (GlobalVariable &G : M.globals())
if (G.hasInitializer())
shuffle(G.getInitializer());
for (GlobalAlias &A : M.aliases())
shuffle(A.getAliasee());
for (Function &F : M)
if (F.hasPrefixData())
shuffle(F.getPrefixData());

// Function bodies.
for (Function &F : M) {
for (Argument &A : F.args())
shuffle(&A);
for (BasicBlock &BB : F)
shuffle(&BB);
for (BasicBlock &BB : F)
for (Instruction &I : BB)
shuffle(&I);

// Constants used by instructions.
for (BasicBlock &BB : F)
for (Instruction &I : BB)
for (Value *Op : I.operands())
if ((isa<Constant>(Op) && !isa<GlobalValue>(*Op)) ||
isa<InlineAsm>(Op))
shuffle(Op);
}

DEBUG(dbgs() << "\n");
}
105 changes: 100 additions & 5 deletions tools/verify-uselistorder/verify-uselistorder.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -11,8 +11,8 @@
// provided IR, this tool shuffles the use-lists and then writes and reads to a
// separate Module whose use-list orders are compared to the original.
//
// The shuffles are deterministic and somewhat naive. On a given shuffle, some
// use-lists will not change at all. The algorithm per iteration is as follows:
// The shuffles are deterministic, but guarantee that use-lists will change.
// The algorithm per iteration is as follows:
//
// 1. Seed the random number generator. The seed is different for each
// shuffle. Shuffle 0 uses default+0, shuffle 1 uses default+1, and so on.
Expand All @@ -21,14 +21,14 @@
//
// 3. Assign a random number to each Use in the Value's use-list in order.
//
// 4. Sort the use-list using Value::sortUseList(), which is a stable sort.
// 4. If the numbers are already in order, reassign numbers until they aren't.
//
// Shuffling a larger number of times provides a better statistical guarantee
// that each use-list has changed at least once.
// 5. Sort the use-list using Value::sortUseList(), which is a stable sort.
//
//===----------------------------------------------------------------------===//

#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/LLVMContext.h"
Expand All @@ -46,6 +46,8 @@
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/SystemUtils.h"
#include <random>
#include <vector>

using namespace llvm;

Expand Down Expand Up @@ -368,6 +370,99 @@ static void verifyUseListOrder(const Module &M) {
report_fatal_error("assembly use-list order changed");
}

static void shuffleValueUseLists(Value *V, std::minstd_rand0 &Gen,
DenseSet<Value *> &Seen) {
if (!Seen.insert(V).second)
return;

if (auto *C = dyn_cast<Constant>(V))
if (!isa<GlobalValue>(C))
for (Value *Op : C->operands())
shuffleValueUseLists(Op, Gen, Seen);

if (V->use_empty() || std::next(V->use_begin()) == V->use_end())
// Nothing to shuffle for 0 or 1 users.
return;

// Generate random numbers between 10 and 99, which will line up nicely in
// debug output. We're not worried about collisons here.
DEBUG(dbgs() << "V = "; V->dump());
std::uniform_int_distribution<short> Dist(10, 99);
SmallDenseMap<const Use *, short, 16> Order;
auto compareUses =
[&Order](const Use &L, const Use &R) { return Order[&L] < Order[&R]; };
do {
for (const Use &U : V->uses()) {
auto I = Dist(Gen);
Order[&U] = I;
DEBUG(dbgs() << " - order: " << I << ", op = " << U.getOperandNo()
<< ", U = ";
U.getUser()->dump());
}
} while (std::is_sorted(V->use_begin(), V->use_end(), compareUses));

DEBUG(dbgs() << " => shuffle\n");
V->sortUseList(compareUses);

DEBUG({
for (const Use &U : V->uses()) {
dbgs() << " - order: " << Order.lookup(&U)
<< ", op = " << U.getOperandNo() << ", U = ";
U.getUser()->dump();
}
});
}

/// Shuffle all use-lists in a module.
void shuffleUseLists(Module &M, unsigned SeedOffset) {
DEBUG(dbgs() << "*** shuffle-use-lists ***\n");
std::minstd_rand0 Gen(std::minstd_rand0::default_seed + SeedOffset);
DenseSet<Value *> Seen;

// Shuffle the use-list of each value that would be serialized to an IR file
// (bitcode or assembly).
auto shuffle = [&](Value *V) { shuffleValueUseLists(V, Gen, Seen); };

// Globals.
for (GlobalVariable &G : M.globals())
shuffle(&G);
for (GlobalAlias &A : M.aliases())
shuffle(&A);
for (Function &F : M)
shuffle(&F);

// Constants used by globals.
for (GlobalVariable &G : M.globals())
if (G.hasInitializer())
shuffle(G.getInitializer());
for (GlobalAlias &A : M.aliases())
shuffle(A.getAliasee());
for (Function &F : M)
if (F.hasPrefixData())
shuffle(F.getPrefixData());

// Function bodies.
for (Function &F : M) {
for (Argument &A : F.args())
shuffle(&A);
for (BasicBlock &BB : F)
shuffle(&BB);
for (BasicBlock &BB : F)
for (Instruction &I : BB)
shuffle(&I);

// Constants used by instructions.
for (BasicBlock &BB : F)
for (Instruction &I : BB)
for (Value *Op : I.operands())
if ((isa<Constant>(Op) && !isa<GlobalValue>(*Op)) ||
isa<InlineAsm>(Op))
shuffle(Op);
}

DEBUG(dbgs() << "\n");
}

int main(int argc, char **argv) {
sys::PrintStackTraceOnErrorSignal();
llvm::PrettyStackTraceProgram X(argc, argv);
Expand Down

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