Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(168)

Unified Diff: lib/Transforms/NaCl/GlobalizeConstantVectors.cpp

Issue 939073008: Rebased PNaCl localmods in LLVM to 223109 (Closed)
Patch Set: undo localmod Created 5 years, 10 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View side-by-side diff with in-line comments
Download patch
« no previous file with comments | « lib/Transforms/NaCl/GlobalCleanup.cpp ('k') | lib/Transforms/NaCl/InsertDivideCheck.cpp » ('j') | no next file with comments »
Expand Comments ('e') | Collapse Comments ('c') | Show Comments Hide Comments ('s')
Index: lib/Transforms/NaCl/GlobalizeConstantVectors.cpp
diff --git a/lib/Transforms/NaCl/GlobalizeConstantVectors.cpp b/lib/Transforms/NaCl/GlobalizeConstantVectors.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..748dfdec7f8bd42480a96fb219cc7f6c68087245
--- /dev/null
+++ b/lib/Transforms/NaCl/GlobalizeConstantVectors.cpp
@@ -0,0 +1,177 @@
+//===- GlobalizeConstantVectors.cpp - Globalize constant vector -----------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass replaces all constant vector operands by loads of the same
+// vector value from a constant global. After this pass functions don't
+// rely on ConstantVector and ConstantDataVector.
+//
+// The FlattenGlobals pass can be used to further simplify the globals
+// that this pass creates.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/NaCl.h"
+#include <utility>
+#include <vector>
+
+using namespace llvm;
+
+namespace {
+// Must be a ModulePass since it adds globals.
+class GlobalizeConstantVectors : public ModulePass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ GlobalizeConstantVectors() : ModulePass(ID), DL(0) {
+ initializeGlobalizeConstantVectorsPass(*PassRegistry::getPassRegistry());
+ }
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.setPreservesCFG();
+ AU.addRequired<DataLayoutPass>();
+ }
+ virtual bool runOnModule(Module &M);
+
+private:
+ typedef SmallPtrSet<Constant *, 64> Constants;
+ typedef std::pair<Function *, Constants> FunctionConstants;
+ typedef std::vector<FunctionConstants> FunctionConstantList;
+ typedef DenseMap<Constant *, GlobalVariable *> GlobalizedConstants;
+ const DataLayout *DL;
+
+ void findConstantVectors(const Function &F, Constants &Cs) const;
+ void createGlobalConstantVectors(Module &M, const FunctionConstantList &FCs,
+ GlobalizedConstants &GCs) const;
+ void materializeConstantVectors(Function &F, const Constants &Cs,
+ const GlobalizedConstants &GCs) const;
+};
+
+const char Name[] = "constant_vector";
+} // anonymous namespace
+
+char GlobalizeConstantVectors::ID = 0;
+INITIALIZE_PASS(GlobalizeConstantVectors, "globalize-constant-vectors",
+ "Replace constant vector operands with equivalent loads", false,
+ false)
+
+void GlobalizeConstantVectors::findConstantVectors(const Function &F,
+ Constants &Cs) const {
+ for (const_inst_iterator II = inst_begin(F), IE = inst_end(F); II != IE;
+ ++II) {
+ for (User::const_op_iterator OI = II->op_begin(), OE = II->op_end();
+ OI != OE; ++OI) {
+ Value *V = OI->get();
+ if (isa<ConstantVector>(V) || isa<ConstantDataVector>(V) ||
+ isa<ConstantAggregateZero>(V))
+ Cs.insert(cast<Constant>(V));
+ }
+ }
+}
+
+void GlobalizeConstantVectors::createGlobalConstantVectors(
+ Module &M, const FunctionConstantList &FCs,
+ GlobalizedConstants &GCs) const {
+ for (FunctionConstantList::const_iterator FCI = FCs.begin(), FCE = FCs.end();
+ FCI != FCE; ++FCI) {
+ const Constants &Cs = FCI->second;
+
+ for (Constants::const_iterator CI = Cs.begin(), CE = Cs.end(); CI != CE;
+ ++CI) {
+ Constant *C = *CI;
+ if (GCs.find(C) != GCs.end())
+ continue; // The vector has already been globalized.
+ GlobalVariable *GV =
+ new GlobalVariable(M, C->getType(), /* isConstant= */ true,
+ GlobalValue::InternalLinkage, C, Name);
+ GV->setAlignment(DL->getPrefTypeAlignment(C->getType()));
+ GV->setUnnamedAddr(true); // The content is significant, not the address.
+ GCs[C] = GV;
+ }
+ }
+}
+
+void GlobalizeConstantVectors::materializeConstantVectors(
+ Function &F, const Constants &Cs, const GlobalizedConstants &GCs) const {
+ // The first instruction in a function dominates all others, it is therefore a
+ // safe insertion point.
+ Instruction *FirstInst = F.getEntryBlock().getFirstNonPHI();
+
+ for (Constants::const_iterator CI = Cs.begin(), CE = Cs.end(); CI != CE;
+ ++CI) {
+ Constant *C = *CI;
+ GlobalizedConstants::const_iterator GVI = GCs.find(C);
+ assert(GVI != GCs.end());
+ GlobalVariable *GV = GVI->second;
+ LoadInst *MaterializedGV = new LoadInst(GV, Name, /* isVolatile= */ false,
+ GV->getAlignment(), FirstInst);
+
+ // Find users of the constant vector.
+ typedef SmallVector<User *, 64> UserList;
+ UserList CVUsers;
+ for (auto U : C->users()) {
+ if (Instruction *I = dyn_cast<Instruction>(U))
+ if (I->getParent()->getParent() != &F)
+ // Skip uses of the constant vector in other functions: we need to
+ // materialize it in every function which has a use.
+ continue;
+ if (isa<Constant>(U))
+ // Don't replace global uses of the constant vector: we just created a
+ // new one. This avoid recursive references.
+ // Also, it's not legal to replace a constant's operand with
+ // a non-constant (the load instruction).
+ continue;
+ CVUsers.push_back(U);
+ }
+
+ // Replace these Users. Must be done separately to avoid invalidating the
+ // User iterator.
+ for (UserList::iterator UI = CVUsers.begin(), UE = CVUsers.end(); UI != UE;
+ ++UI) {
+ User *U = *UI;
+ for (User::op_iterator OI = U->op_begin(), OE = U->op_end(); OI != OE;
+ ++OI)
+ if (dyn_cast<Constant>(*OI) == C)
+ // The current operand is a use of the constant vector, replace it
+ // with the materialized one.
+ *OI = MaterializedGV;
+ }
+ }
+}
+
+bool GlobalizeConstantVectors::runOnModule(Module &M) {
+ DL = &getAnalysis<DataLayoutPass>().getDataLayout();
+
+ FunctionConstantList FCs;
+ FCs.reserve(M.size());
+ for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
+ Constants Cs;
+ findConstantVectors(*FI, Cs);
+ if (!Cs.empty())
+ FCs.push_back(std::make_pair(&*FI, Cs));
+ }
+
+ GlobalizedConstants GCs;
+ createGlobalConstantVectors(M, FCs, GCs);
+
+ for (FunctionConstantList::const_iterator FCI = FCs.begin(), FCE = FCs.end();
+ FCI != FCE; ++FCI)
+ materializeConstantVectors(*FCI->first, FCI->second, GCs);
+
+ return FCs.empty();
+}
+
+ModulePass *llvm::createGlobalizeConstantVectorsPass() {
+ return new GlobalizeConstantVectors();
+}
« no previous file with comments | « lib/Transforms/NaCl/GlobalCleanup.cpp ('k') | lib/Transforms/NaCl/InsertDivideCheck.cpp » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698