Add BasicInliner interface.

This interface allows clients to inline bunch of functions with module
level call graph information.:wq



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40486 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 171 insertions, 0 deletions

diff --git a/lib/Transforms/Utils/BasicInliner.cpp b/lib/Transforms/Utils/BasicInliner.cpp
new file mode 100644
index 0000000000..871b1a504a
--- /dev/null
+++ b/lib/Transforms/Utils/BasicInliner.cpp
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+//===- BasicInliner.cpp - Basic function level inliner --------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by Devang Patel and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines a simple function based inliner that does not use
+// call graph information. 
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "basicinliner"
+
+#include "llvm/Module.h"
+#include "llvm/Function.h"
+#include "llvm/Transforms/Utils/BasicInliner.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Support/CallSite.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include <vector>
+#include <set>
+
+using namespace llvm;
+
+namespace {
+  cl::opt<unsigned>     
+  BasicInlineThreshold("inline-threshold", cl::Hidden, cl::init(200),
+                       cl::desc("Control the amount of basic inlining to perform (default = 200)"));
+}
+
+namespace llvm {
+
+  /// BasicInlinerImpl - BasicInliner implemantation class. This hides
+  /// container info, used by basic inliner, from public interface.
+  struct VISIBILITY_HIDDEN BasicInlinerImpl {
+    
+    BasicInlinerImpl(const BasicInlinerImpl&); // DO NOT IMPLEMENT
+    void operator=(const BasicInlinerImpl&); // DO NO IMPLEMENT
+  public:
+    BasicInlinerImpl(TargetData *T) : TD(T) {}
+
+    /// addFunction - Add function into the list of functions to process.
+    /// All functions must be inserted using this interface before invoking
+    /// inlineFunctions().
+    void addFunction(Function *F) {
+      Functions.push_back(F);
+    }
+
+    /// neverInlineFunction - Sometimes a function is never to be inlined 
+    /// because of one or other reason. 
+    void neverInlineFunction(Function *F) {
+      NeverInline.insert(F);
+    }
+
+    /// inlineFuctions - Walk all call sites in all functions supplied by
+    /// client. Inline as many call sites as possible. Delete completely
+    /// inlined functions.
+    void inlineFunctions();
+    
+  private:
+    TargetData *TD;
+    std::vector<Function *> Functions;
+    std::set<const Function *> NeverInline;
+    SmallPtrSet<Function *, 8> DeadFunctions;
+    InlineCostAnalyzer CA;
+  };
+
+/// inlineFuctions - Walk all call sites in all functions supplied by
+/// client. Inline as many call sites as possible. Delete completely
+/// inlined functions.
+void BasicInlinerImpl::inlineFunctions() {
+      
+  // Scan through and identify all call sites ahead of time so that we only
+  // inline call sites in the original functions, not call sites that result
+  // from inlining other functions.
+  std::vector<CallSite> CallSites;
+  
+  for (std::vector<Function *>::iterator FI = Functions.begin(),
+         FE = Functions.end(); FI != FE; ++FI) {
+    Function *F = *FI;
+    for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
+      for (BasicBlock::iterator I = BB->begin(); I != BB->end(); ++I) {
+        CallSite CS = CallSite::get(I);
+        if (CS.getInstruction() && CS.getCalledFunction()
+            && !CS.getCalledFunction()->isDeclaration())
+          CallSites.push_back(CS);
+      }
+  }
+  
+  DOUT << ": " << CallSites.size() << " call sites.\n";
+  
+  // Inline call sites.
+  bool Changed = false;
+  do {
+    Changed = false;
+    for (unsigned index = 0; index != CallSites.size() && !CallSites.empty(); ++index) {
+      CallSite CS = CallSites[index];
+      if (Function *Callee = CS.getCalledFunction()) {
+        
+        // Eliminate calls taht are never inlinable.
+        if (Callee->isDeclaration() ||
+            CS.getInstruction()->getParent()->getParent() == Callee) {
+          CallSites.erase(CallSites.begin() + index);
+              --index;
+              continue;
+        }
+        int InlineCost = CA.getInlineCost(CS, NeverInline);
+        if (InlineCost >= (int) BasicInlineThreshold) {
+              DOUT << "  NOT Inlining: cost = " << InlineCost
+                   << ", call: " <<  *CS.getInstruction();
+              continue;
+        }
+        
+        DOUT << "  Inlining: cost=" << InlineCost
+             <<", call: " << *CS.getInstruction();
+        
+        // Inline
+        if (InlineFunction(CS, NULL, TD)) {
+          if (Callee->use_empty() && Callee->hasInternalLinkage())
+                DeadFunctions.insert(Callee);
+          Changed = true;
+          CallSites.erase(CallSites.begin() + index);
+          --index;
+        }
+      }
+    }
+  } while (Changed);
+  
+  // Remove completely inlined functions from module.
+  for(SmallPtrSet<Function *, 8>::iterator I = DeadFunctions.begin(),
+        E = DeadFunctions.end(); I != E; ++I) {
+    Function *D = *I;
+    Module *M = D->getParent();
+    M->getFunctionList().remove(D);
+  }
+}
+
+BasicInliner::BasicInliner(TargetData *TD) {
+  Impl = new BasicInlinerImpl(TD);
+}
+
+BasicInliner::~BasicInliner() {
+  delete Impl;
+}
+
+/// addFunction - Add function into the list of functions to process.
+/// All functions must be inserted using this interface before invoking
+/// inlineFunctions().
+void BasicInliner::addFunction(Function *F) {
+  Impl->addFunction(F);
+}
+
+/// neverInlineFunction - Sometimes a function is never to be inlined because
+/// of one or other reason. 
+void BasicInliner::neverInlineFunction(Function *F) {
+  Impl->neverInlineFunction(F);
+}
+
+/// inlineFuctions - Walk all call sites in all functions supplied by
+/// client. Inline as many call sites as possible. Delete completely
+/// inlined functions.
+void BasicInliner::inlineFunctions() {
+  Impl->inlineFunctions();
+}
+
+}