-//===- UseListOrder.cpp - Implement Use List Order functions --------------===//
+//===- UseListOrder.cpp - Implement Use List Order ------------------------===//
//
// The LLVM Compiler Infrastructure
//
//
//===----------------------------------------------------------------------===//
//
-// 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;
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");
-}
// 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.
//
// 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"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/SystemUtils.h"
+#include <random>
+#include <vector>
using namespace llvm;
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);
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