Loop invariant code motion now depends on the LoopPreheader pass. Dead code

[oota-llvm.git] / lib / Transforms / IPO / DeadTypeElimination.cpp

diff --git a/lib/Transforms/IPO/DeadTypeElimination.cpp b/lib/Transforms/IPO/DeadTypeElimination.cpp
index 9fd912a1adc9461dc289795f6fdcb1bea0bd023e..58fe7f0a595b7d7014285b8fd4013e9056460dc7 100644 (file)
--- a/lib/Transforms/IPO/DeadTypeElimination.cpp
+++ b/lib/Transforms/IPO/DeadTypeElimination.cpp
@@ -1,67 +1,97 @@
-//===- CleanupGCCOutput.cpp - Cleanup GCC Output ----------------------------=//
+//===- DeadTypeElimination.cpp - Eliminate unused types for symbol table --===//
 //
-// This pass is used to cleanup the output of GCC.  GCC's output is
-// unneccessarily gross for a couple of reasons. This pass does the following
-// things to try to clean it up:
-//
-// Note:  This code produces dead declarations, it is a good idea to run DCE
-//        after this pass.
+// This pass is used to cleanup the output of GCC.  It eliminate names for types
+// that are unused in the entire translation unit, using the FindUsedTypes pass.
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/Transforms/CleanupGCCOutput.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Analysis/FindUsedTypes.h"
+#include "llvm/Module.h"
 #include "llvm/SymbolTable.h"
+#include "llvm/DerivedTypes.h"
+#include "Support/StatisticReporter.h"
+
+using std::vector;
+
+namespace {
+  struct DTE : public Pass {
+    // doPassInitialization - For this pass, it removes global symbol table
+    // entries for primitive types.  These are never used for linking in GCC and
+    // they make the output uglier to look at, so we nuke them.
+    //
+    // Also, initialize instance variables.
+    //
+    bool run(Module &M);
+
+    // getAnalysisUsage - This function needs FindUsedTypes to do its job...
+    //
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.addRequired<FindUsedTypes>();
+    }
+  };
+  RegisterOpt<DTE> X("deadtypeelim", "Dead Type Elimination");
+  Statistic<> NumKilled("deadtypeelim\t- Number of unused typenames removed from symtab");
+}
+
+Pass *createDeadTypeEliminationPass() {
+  return new DTE();
+}
+
+
 
-static inline bool ShouldNukeSymtabEntry(const pair<string, Value*> &E) {
+// ShouldNukSymtabEntry - Return true if this module level symbol table entry
+// should be eliminated.
+//
+static inline bool ShouldNukeSymtabEntry(const std::pair<std::string,Value*>&E){
   // Nuke all names for primitive types!
   if (cast<Type>(E.second)->isPrimitiveType()) return true;
 
-  // The only types that could contain .'s in the program are things generated
-  // by GCC itself, including "complex.float" and friends.  Nuke them too.
-  if (E.first.find('.') != string::npos) return true;
+  // Nuke all pointers to primitive types as well...
+  if (const PointerType *PT = dyn_cast<PointerType>(E.second))
+    if (PT->getElementType()->isPrimitiveType()) return true;
 
   return false;
 }
 
-
-// doPassInitialization - For this pass, it removes global symbol table
-// entries for primitive types.  These are never used for linking in GCC and
-// they make the output uglier to look at, so we nuke them.
+// run - For this pass, it removes global symbol table entries for primitive
+// types.  These are never used for linking in GCC and they make the output
+// uglier to look at, so we nuke them.  Also eliminate types that are never used
+// in the entire program as indicated by FindUsedTypes.
 //
-bool CleanupGCCOutput::doPassInitialization(Module *M) {
+bool DTE::run(Module &M) {
   bool Changed = false;
 
-  if (M->hasSymbolTable()) {
-    // Grab the type plane of the module...
-    SymbolTable *ST = M->getSymbolTable();
+  if (SymbolTable *ST = M.getSymbolTable()) {
+    const std::set<const Type *> &UsedTypes =
+      getAnalysis<FindUsedTypes>().getTypes();
+
+    // Check the symbol table for superfluous type entries...
+    //
+    // Grab the 'type' plane of the module symbol...
     SymbolTable::iterator STI = ST->find(Type::TypeTy);
     if (STI != ST->end()) {
       // Loop over all entries in the type plane...
       SymbolTable::VarMap &Plane = STI->second;
       for (SymbolTable::VarMap::iterator PI = Plane.begin(); PI != Plane.end();)
-        if (ShouldNukeSymtabEntry(*PI)) {    // Should we remove this entry?
+        // If this entry should be unconditionally removed, or if we detect that
+        // the type is not used, remove it.
+        //
+        if (ShouldNukeSymtabEntry(*PI) ||
+            !UsedTypes.count(cast<Type>(PI->second))) {
 #if MAP_IS_NOT_BRAINDEAD
           PI = Plane.erase(PI);     // STD C++ Map should support this!
 #else
           Plane.erase(PI);          // Alas, GCC 2.95.3 doesn't  *SIGH*
           PI = Plane.begin();
 #endif
+          ++NumKilled;
           Changed = true;
         } else {
           ++PI;
         }
     }
-    
   }
 
   return Changed;
 }
-
-
-// doPerMethodWork - This method simplifies the specified method hopefully.
-//
-bool CleanupGCCOutput::doPerMethodWork(Method *M) {
-  bool Changed = false;
-
-  return Changed;
-}