Revert "Revert r347596 "Support for inserting profile-directed cache prefetches""
Summary:
This reverts commit d8517b96dfbd42e6a8db33c50d1fa1e58e63fbb9.
Fix: correct the use of DenseMap.
Reviewers: davidxl, hans, wmi
Reviewed By: wmi
Subscribers: mgorny, eraman, llvm-commits
Differential Revision: https://reviews.llvm.org/D55088
llvm-svn: 347938
diff --git a/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp b/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp
new file mode 100644
index 0000000..4935896
--- /dev/null
+++ b/llvm/lib/Target/X86/X86DiscriminateMemOps.cpp
@@ -0,0 +1,132 @@
+//===- X86DiscriminateMemOps.cpp - Unique IDs for Mem Ops -----------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+///
+/// This pass aids profile-driven cache prefetch insertion by ensuring all
+/// instructions that have a memory operand are distinguishible from each other.
+///
+//===----------------------------------------------------------------------===//
+
+#include "X86.h"
+#include "X86InstrBuilder.h"
+#include "X86InstrInfo.h"
+#include "X86MachineFunctionInfo.h"
+#include "X86Subtarget.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+#include "llvm/ProfileData/SampleProf.h"
+#include "llvm/ProfileData/SampleProfReader.h"
+#include "llvm/Transforms/IPO/SampleProfile.h"
+using namespace llvm;
+
+namespace {
+
+using Location = std::pair<StringRef, unsigned>;
+
+Location diToLocation(const DILocation *Loc) {
+ return std::make_pair(Loc->getFilename(), Loc->getLine());
+}
+
+/// Ensure each instruction having a memory operand has a distinct <LineNumber,
+/// Discriminator> pair.
+void updateDebugInfo(MachineInstr *MI, const DILocation *Loc) {
+ DebugLoc DL(Loc);
+ MI->setDebugLoc(DL);
+}
+
+class X86DiscriminateMemOps : public MachineFunctionPass {
+ bool runOnMachineFunction(MachineFunction &MF) override;
+ StringRef getPassName() const override {
+ return "X86 Discriminate Memory Operands";
+ }
+
+public:
+ static char ID;
+
+ /// Default construct and initialize the pass.
+ X86DiscriminateMemOps();
+};
+
+} // end anonymous namespace
+
+//===----------------------------------------------------------------------===//
+// Implementation
+//===----------------------------------------------------------------------===//
+
+char X86DiscriminateMemOps::ID = 0;
+
+/// Default construct and initialize the pass.
+X86DiscriminateMemOps::X86DiscriminateMemOps() : MachineFunctionPass(ID) {}
+
+bool X86DiscriminateMemOps::runOnMachineFunction(MachineFunction &MF) {
+ DISubprogram *FDI = MF.getFunction().getSubprogram();
+ if (!FDI || !FDI->getUnit()->getDebugInfoForProfiling())
+ return false;
+
+ // Have a default DILocation, if we find instructions with memops that don't
+ // have any debug info.
+ const DILocation *ReferenceDI =
+ DILocation::get(FDI->getContext(), FDI->getLine(), 0, FDI);
+
+ DenseMap<Location, unsigned> MemOpDiscriminators;
+ MemOpDiscriminators[diToLocation(ReferenceDI)] = 0;
+
+ // Figure out the largest discriminator issued for each Location. When we
+ // issue new discriminators, we can thus avoid issuing discriminators
+ // belonging to instructions that don't have memops. This isn't a requirement
+ // for the goals of this pass, however, it avoids unnecessary ambiguity.
+ for (auto &MBB : MF) {
+ for (auto &MI : MBB) {
+ const auto &DI = MI.getDebugLoc();
+ if (!DI)
+ continue;
+ Location Loc = diToLocation(DI);
+ MemOpDiscriminators[Loc] =
+ std::max(MemOpDiscriminators[Loc], DI->getBaseDiscriminator());
+ }
+ }
+
+ // Keep track of the discriminators seen at each Location. If an instruction's
+ // DebugInfo has a Location and discriminator we've already seen, replace its
+ // discriminator with a new one, to guarantee uniqueness.
+ DenseMap<Location, DenseSet<unsigned>> Seen;
+
+ bool Changed = false;
+ for (auto &MBB : MF) {
+ for (auto &MI : MBB) {
+ if (X86II::getMemoryOperandNo(MI.getDesc().TSFlags) < 0)
+ continue;
+ const DILocation *DI = MI.getDebugLoc();
+ if (!DI) {
+ DI = ReferenceDI;
+ }
+ DenseSet<unsigned> &Set = Seen[diToLocation(DI)];
+ const std::pair<DenseSet<unsigned>::iterator, bool> TryInsert =
+ Set.insert(DI->getBaseDiscriminator());
+ if (!TryInsert.second) {
+ DI = DI->setBaseDiscriminator(++MemOpDiscriminators[diToLocation(DI)]);
+ updateDebugInfo(&MI, DI);
+ Changed = true;
+ const std::pair<DenseSet<unsigned>::iterator, bool> MustInsert =
+ Set.insert(DI->getBaseDiscriminator());
+ assert(MustInsert.second);
+ }
+
+ // Bump the reference DI to avoid cramming discriminators on line 0.
+ // FIXME(mtrofin): pin ReferenceDI on blocks or first instruction with DI
+ // in a block. It's more consistent than just relying on the last memop
+ // instruction we happened to see.
+ ReferenceDI = DI;
+ }
+ }
+ return Changed;
+}
+
+FunctionPass *llvm::createX86DiscriminateMemOpsPass() {
+ return new X86DiscriminateMemOps();
+}