It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/StripSymbols.cpp b/lib/Transforms/IPO/StripSymbols.cpp
new file mode 100644
index 0000000..c8f8926
--- /dev/null
+++ b/lib/Transforms/IPO/StripSymbols.cpp
@@ -0,0 +1,206 @@
+//===- StripSymbols.cpp - Strip symbols and debug info from a module ------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements stripping symbols out of symbol tables.
+//
+// Specifically, this allows you to strip all of the symbols out of:
+//   * All functions in a module
+//   * All non-essential symbols in a module (all function symbols + all module
+//     scope symbols)
+//   * Debug information.
+//
+// Notice that:
+//   * This pass makes code much less readable, so it should only be used in
+//     situations where the 'strip' utility would be used (such as reducing
+//     code size, and making it harder to reverse engineer code).
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/ValueSymbolTable.h"
+#include "llvm/TypeSymbolTable.h"
+#include "llvm/Support/Compiler.h"
+using namespace llvm;
+
+namespace {
+  class VISIBILITY_HIDDEN StripSymbols : public ModulePass {
+    bool OnlyDebugInfo;
+  public:
+    static char ID; // Pass identification, replacement for typeid
+    StripSymbols(bool ODI = false) 
+      : ModulePass((intptr_t)&ID), OnlyDebugInfo(ODI) {}
+
+    virtual bool runOnModule(Module &M);
+
+    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+      AU.setPreservesAll();
+    }
+  };
+
+  char StripSymbols::ID = 0;
+  RegisterPass<StripSymbols> X("strip", "Strip all symbols from a module");
+}
+
+ModulePass *llvm::createStripSymbolsPass(bool OnlyDebugInfo) {
+  return new StripSymbols(OnlyDebugInfo);
+}
+
+static void RemoveDeadConstant(Constant *C) {
+  assert(C->use_empty() && "Constant is not dead!");
+  std::vector<Constant*> Operands;
+  for (unsigned i = 0, e = C->getNumOperands(); i != e; ++i)
+    if (isa<DerivedType>(C->getOperand(i)->getType()) &&
+        C->getOperand(i)->hasOneUse())
+      Operands.push_back(C->getOperand(i));
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C)) {
+    if (!GV->hasInternalLinkage()) return;   // Don't delete non static globals.
+    GV->eraseFromParent();
+  }
+  else if (!isa<Function>(C))
+    C->destroyConstant();
+
+  // If the constant referenced anything, see if we can delete it as well.
+  while (!Operands.empty()) {
+    RemoveDeadConstant(Operands.back());
+    Operands.pop_back();
+  }
+}
+
+// Strip the symbol table of its names.
+//
+static void StripSymtab(ValueSymbolTable &ST) {
+  for (ValueSymbolTable::iterator VI = ST.begin(), VE = ST.end(); VI != VE; ) {
+    Value *V = VI->getValue();
+    ++VI;
+    if (!isa<GlobalValue>(V) || cast<GlobalValue>(V)->hasInternalLinkage()) {
+      // Set name to "", removing from symbol table!
+      V->setName("");
+    }
+  }
+}
+
+// Strip the symbol table of its names.
+static void StripTypeSymtab(TypeSymbolTable &ST) {
+  for (TypeSymbolTable::iterator TI = ST.begin(), E = ST.end(); TI != E; )
+    ST.remove(TI++);
+}
+
+
+
+bool StripSymbols::runOnModule(Module &M) {
+  // If we're not just stripping debug info, strip all symbols from the
+  // functions and the names from any internal globals.
+  if (!OnlyDebugInfo) {
+    for (Module::global_iterator I = M.global_begin(), E = M.global_end();
+         I != E; ++I)
+      if (I->hasInternalLinkage())
+        I->setName("");     // Internal symbols can't participate in linkage
+
+    for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
+      if (I->hasInternalLinkage())
+        I->setName("");     // Internal symbols can't participate in linkage
+      StripSymtab(I->getValueSymbolTable());
+    }
+    
+    // Remove all names from types.
+    StripTypeSymtab(M.getTypeSymbolTable());
+  }
+
+  // Strip debug info in the module if it exists.  To do this, we remove
+  // llvm.dbg.func.start, llvm.dbg.stoppoint, and llvm.dbg.region.end calls, and
+  // any globals they point to if now dead.
+  Function *FuncStart = M.getFunction("llvm.dbg.func.start");
+  Function *StopPoint = M.getFunction("llvm.dbg.stoppoint");
+  Function *RegionStart = M.getFunction("llvm.dbg.region.start");
+  Function *RegionEnd = M.getFunction("llvm.dbg.region.end");
+  Function *Declare = M.getFunction("llvm.dbg.declare");
+  if (!FuncStart && !StopPoint && !RegionStart && !RegionEnd && !Declare)
+    return true;
+
+  std::vector<GlobalVariable*> DeadGlobals;
+
+  // Remove all of the calls to the debugger intrinsics, and remove them from
+  // the module.
+  if (FuncStart) {
+    while (!FuncStart->use_empty()) {
+      CallInst *CI = cast<CallInst>(FuncStart->use_back());
+      Value *Arg = CI->getOperand(1);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg->use_empty())
+        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
+          DeadGlobals.push_back(GV);
+    }
+    FuncStart->eraseFromParent();
+  }
+  if (StopPoint) {
+    while (!StopPoint->use_empty()) {
+      CallInst *CI = cast<CallInst>(StopPoint->use_back());
+      Value *Arg = CI->getOperand(3);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg->use_empty())
+        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
+          DeadGlobals.push_back(GV);
+    }
+    StopPoint->eraseFromParent();
+  }
+  if (RegionStart) {
+    while (!RegionStart->use_empty()) {
+      CallInst *CI = cast<CallInst>(RegionStart->use_back());
+      Value *Arg = CI->getOperand(1);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg->use_empty())
+        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
+          DeadGlobals.push_back(GV);
+    }
+    RegionStart->eraseFromParent();
+  }
+  if (RegionEnd) {
+    while (!RegionEnd->use_empty()) {
+      CallInst *CI = cast<CallInst>(RegionEnd->use_back());
+      Value *Arg = CI->getOperand(1);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg->use_empty())
+        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
+          DeadGlobals.push_back(GV);
+    }
+    RegionEnd->eraseFromParent();
+  }
+  if (Declare) {
+    while (!Declare->use_empty()) {
+      CallInst *CI = cast<CallInst>(Declare->use_back());
+      Value *Arg = CI->getOperand(2);
+      assert(CI->use_empty() && "llvm.dbg intrinsic should have void result");
+      CI->eraseFromParent();
+      if (Arg->use_empty())
+        if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Arg))
+          DeadGlobals.push_back(GV);
+    }
+    Declare->eraseFromParent();
+  }
+
+  // Finally, delete any internal globals that were only used by the debugger
+  // intrinsics.
+  while (!DeadGlobals.empty()) {
+    GlobalVariable *GV = DeadGlobals.back();
+    DeadGlobals.pop_back();
+    if (GV->hasInternalLinkage())
+      RemoveDeadConstant(GV);
+  }
+
+  return true;
+}