[llvm] r254583 - Refactor FunctionImporter::importFunctions with a helper function to process the Worklist (NFC)

[Mehdi Amini via llvm-commits]

Author: mehdi_amini
Date: Wed Dec  2 20:37:33 2015
New Revision: 254583

URL: http://llvm.org/viewvc/llvm-project?rev=254583&view=rev
Log:
Refactor FunctionImporter::importFunctions with a helper function to process the Worklist (NFC)

This precludes some more functional changes to perform bulk imports.

From: Mehdi Amini <mehdi.amini at apple.com>

Modified:
    llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp

Modified: llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp?rev=254583&r1=254582&r2=254583&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp (original)
+++ llvm/trunk/lib/Transforms/IPO/FunctionImport.cpp Wed Dec  2 20:37:33 2015
@@ -66,7 +66,6 @@ static void findExternalCalls(const Func
   for (auto &BB : F) {
     for (auto &I : BB) {
       if (isa<CallInst>(I)) {
-        DEBUG(dbgs() << "Found a call: '" << I << "'\n");
         auto CalledFunction = cast<CallInst>(I).getCalledFunction();
         // Insert any new external calls that have not already been
         // added to set/worklist.
@@ -81,28 +80,14 @@ static void findExternalCalls(const Func
   }
 }
 
-// Automatically import functions in Module \p M based on the summaries index.
-//
-// The current implementation imports every called functions that exists in the
-// summaries index.
-bool FunctionImporter::importFunctions(Module &M) {
-
-  bool Changed = false;
-
-  /// First step is collecting the called external functions.
-  StringSet<> CalledFunctions;
-  SmallVector<StringRef, 64> Worklist;
-  for (auto &F : M) {
-    if (F.isDeclaration() || F.hasFnAttribute(Attribute::OptimizeNone))
-      continue;
-    findExternalCalls(F, CalledFunctions, Worklist);
-  }
-
-  /// Second step: for every call to an external function, try to import it.
-
-  // Linker that will be used for importing function
-  Linker L(M, DiagnosticHandler);
 
+// Helper function: given a worklist and an index, will process all the worklist
+// and import them based on the summary information
+static unsigned ProcessImportWorklist(Module &DestModule, SmallVector<StringRef, 64> &Worklist,
+                                      StringSet<> &CalledFunctions,
+                            Linker &TheLinker, const FunctionInfoIndex &Index,
+                            std::function<Module &(StringRef FileName)> &LazyModuleLoader) {
+  unsigned ImportCount = 0;
   while (!Worklist.empty()) {
     auto CalledFunctionName = Worklist.pop_back_val();
     DEBUG(dbgs() << "Process import for " << CalledFunctionName << "\n");
@@ -141,14 +126,14 @@ bool FunctionImporter::importFunctions(M
                  << "\n");
 
     // Get the module for the import (potentially from the cache).
-    auto &Module = getLazyModule(FileName);
-    assert(&Module.getContext() == &M.getContext());
+    auto &Module = LazyModuleLoader(FileName);
+    assert(&Module.getContext() == &DestModule.getContext());
 
     // The function that we will import!
     GlobalValue *SGV = Module.getNamedValue(CalledFunctionName);
     StringRef ImportFunctionName = CalledFunctionName;
     if (!SGV) {
-      // Might be local in source Module, promoted/renamed in dest Module M.
+      // Might be local in source Module, promoted/renamed in DestModule.
       std::pair<StringRef, StringRef> Split =
           CalledFunctionName.split(".llvm.");
       SGV = Module.getNamedValue(Split.first);
@@ -184,21 +169,52 @@ bool FunctionImporter::importFunctions(M
     // Link in the specified function.
     DenseSet<const GlobalValue *> FunctionsToImport;
     FunctionsToImport.insert(F);
-    if (L.linkInModule(Module, Linker::Flags::None, &Index,
+    if (TheLinker.linkInModule(Module, Linker::Flags::None, &Index,
                        &FunctionsToImport))
       report_fatal_error("Function Import: link error");
 
     // Process the newly imported function and add callees to the worklist.
-    GlobalValue *NewGV = M.getNamedValue(ImportFunctionName);
+    GlobalValue *NewGV = DestModule.getNamedValue(ImportFunctionName);
     assert(NewGV);
     Function *NewF = dyn_cast<Function>(NewGV);
     assert(NewF);
     findExternalCalls(*NewF, CalledFunctions, Worklist);
+    ++ImportCount;
+  }
+  return ImportCount;
+}
+
+// Automatically import functions in Module \p DestModule based on the summaries
+// index.
+//
+// The current implementation imports every called functions that exists in the
+// summaries index.
+bool FunctionImporter::importFunctions(Module &DestModule) {
+  DEBUG(errs() << "Starting import for Module " << DestModule.getModuleIdentifier()
+               << "\n");
+  unsigned ImportedCount = 0;
 
-    Changed = true;
+  /// First step is collecting the called external functions.
+  StringSet<> CalledFunctions;
+  SmallVector<StringRef, 64> Worklist;
+  for (auto &F : DestModule) {
+    if (F.isDeclaration() || F.hasFnAttribute(Attribute::OptimizeNone))
+      continue;
+    findExternalCalls(F, CalledFunctions, Worklist);
   }
+  if (Worklist.empty())
+    return false;
+
+  /// Second step: for every call to an external function, try to import it.
+
+  // Linker that will be used for importing function
+  Linker TheLinker(DestModule, DiagnosticHandler);
+
+  ImportedCount += ProcessImportWorklist(DestModule, Worklist, CalledFunctions, TheLinker, Index, getLazyModule );
 
-  return Changed;
+  DEBUG(errs() << "Imported " << ImportedCount << " functions for Module "
+               << DestModule.getModuleIdentifier() << "\n");
+  return ImportedCount;
 }
 
 /// Summary file to use for function importing when using -function-import from