llvm/lib/Target/NVPTX/NVPTXAllocaHoisting.h
Chandler Carruth 52334f2ad8 [LPM] Stop using the string based preservation API. It is an
abomination.

For starters, this API is incredibly slow. In order to lookup the name
of a pass it must take a memory fence to acquire a pointer to the
managed static pass registry, and then potentially acquire locks while
it consults this registry for information about what passes exist by
that name. This stops the world of LLVMs in your process no matter
how little they cared about the result.

To make this more joyful, you'll note that we are preserving many passes
which *do not exist* any more, or are not even analyses which one might
wish to have be preserved. This means we do all the work only to say
"nope" with no error to the user.

String-based APIs are a *bad idea*. String-based APIs that cannot
produce any meaningful error are an even worse idea. =/

I have a patch that simply removes this API completely, but I'm hesitant
to commit it as I don't really want to perniciously break out-of-tree
users of the old pass manager. I'd rather they just have to migrate to
the new one at some point. If others disagree and would like me to kill
it with fire, just say the word. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@227294 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-28 04:57:56 +00:00

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//===-- AllocaHoisting.h - Hosist allocas to the entry block ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Hoist the alloca instructions in the non-entry blocks to the entry blocks.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_LIB_TARGET_NVPTX_NVPTXALLOCAHOISTING_H
#define LLVM_LIB_TARGET_NVPTX_NVPTXALLOCAHOISTING_H
#include "llvm/CodeGen/MachineFunctionAnalysis.h"
#include "llvm/CodeGen/StackProtector.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/Pass.h"
namespace llvm {
class FunctionPass;
class Function;
// Hoisting the alloca instructions in the non-entry blocks to the entry
// block.
class NVPTXAllocaHoisting : public FunctionPass {
public:
static char ID; // Pass ID
NVPTXAllocaHoisting() : FunctionPass(ID) {}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<DataLayoutPass>();
AU.addPreserved<MachineFunctionAnalysis>();
AU.addPreserved<StackProtector>();
}
const char *getPassName() const override {
return "NVPTX specific alloca hoisting";
}
bool runOnFunction(Function &function) override;
};
extern FunctionPass *createAllocaHoisting();
} // end namespace llvm
#endif