llvm-6502/unittests/IR/PassManagerTest.cpp
Chandler Carruth f348c9782c Introduce an AnalysisManager which is like a pass manager but with a lot
more smarts in it. This is where most of the interesting logic that used
to live in the implicit-scheduling-hackery of the old pass manager will
live.

Like the previous commits, note that this is a very early prototype!
I expect substantial changes before this is ready to use.

The core of the design is the following:

- We have an AnalysisManager which can be used across a series of
  passes over a module.
- The code setting up a pass pipeline registers the analyses available
  with the manager.
- Individual transform passes can check than an analysis manager
  provides the analyses they require in order to fail-fast.
- There is *no* implicit registration or scheduling.
- Analysis passes are different from other passes: they produce an
  analysis result that is cached and made available via the analysis
  manager.
- Cached results are invalidated automatically by the pass managers.
- When a transform pass requests an analysis result, either the analysis
  is run to produce the result or a cached result is provided.

There are a few aspects of this design that I *know* will change in
subsequent commits:
- Currently there is no "preservation" system, that needs to be added.
- All of the analysis management should move up to the analysis library.
- The analysis management needs to support at least SCC passes. Maybe
  loop passes. Living in the analysis library will facilitate this.
- Need support for analyses which are *both* module and function passes.
- Need support for pro-actively running module analyses to have cached
  results within a function pass manager.
- Need a clear design for "immutable" passes.
- Need support for requesting cached results when available and not
  re-running the pass even if that would be necessary.
- Need more thorough testing of all of this infrastructure.

There are other aspects that I view as open questions I'm hoping to
resolve as I iterate a bit on the infrastructure, and especially as
I start writing actual passes against this.
- Should we have separate management layers for function, module, and
  SCC analyses? I think "yes", but I'm not yet ready to switch the code.
  Adding SCC support will likely resolve this definitively.
- How should the 'require' functionality work? Should *that* be the only
  way to request results to ensure that passes always require things?
- How should preservation work?
- Probably some other things I'm forgetting. =]

Look forward to more patches in shorter order now that this is in place.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194538 91177308-0d34-0410-b5e6-96231b3b80d8
2013-11-13 01:12:08 +00:00

133 lines
3.3 KiB
C++

//===- llvm/unittest/IR/PassManager.cpp - PassManager tests ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Assembly/Parser.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Support/SourceMgr.h"
#include "gtest/gtest.h"
using namespace llvm;
namespace {
class TestAnalysisPass {
public:
typedef Function IRUnitT;
struct Result {
Result(int Count) : InstructionCount(Count) {}
bool invalidate(Function *) { return true; }
int InstructionCount;
};
/// \brief Returns an opaque, unique ID for this pass type.
static void *ID() { return (void *)&PassID; }
/// \brief Run the analysis pass over the function and return a result.
Result run(Function *F) {
int Count = 0;
for (Function::iterator BBI = F->begin(), BBE = F->end(); BBI != BBE; ++BBI)
for (BasicBlock::iterator II = BBI->begin(), IE = BBI->end(); II != IE;
++II)
++Count;
return Result(Count);
}
private:
/// \brief Private static data to provide unique ID.
static char PassID;
};
char TestAnalysisPass::PassID;
struct TestModulePass {
TestModulePass(int &RunCount) : RunCount(RunCount) {}
bool run(Module *M) {
++RunCount;
return true;
}
int &RunCount;
};
struct TestFunctionPass {
TestFunctionPass(AnalysisManager &AM, int &RunCount, int &AnalyzedInstrCount)
: AM(AM), RunCount(RunCount), AnalyzedInstrCount(AnalyzedInstrCount) {
AM.requireAnalysisPass<TestAnalysisPass>();
}
bool run(Function *F) {
++RunCount;
const TestAnalysisPass::Result &AR = AM.getResult<TestAnalysisPass>(F);
AnalyzedInstrCount += AR.InstructionCount;
return true;
}
AnalysisManager &AM;
int &RunCount;
int &AnalyzedInstrCount;
};
Module *parseIR(const char *IR) {
LLVMContext &C = getGlobalContext();
SMDiagnostic Err;
return ParseAssemblyString(IR, 0, Err, C);
}
class PassManagerTest : public ::testing::Test {
protected:
OwningPtr<Module> M;
public:
PassManagerTest()
: M(parseIR("define void @f() {\n"
"entry:\n"
" call void @g()\n"
" call void @h()\n"
" ret void\n"
"}\n"
"define void @g() {\n"
" ret void\n"
"}\n"
"define void @h() {\n"
" ret void\n"
"}\n")) {}
};
TEST_F(PassManagerTest, Basic) {
AnalysisManager AM(M.get());
AM.registerAnalysisPass(TestAnalysisPass());
ModulePassManager MPM(M.get(), &AM);
FunctionPassManager FPM(&AM);
// Count the runs over a module.
int ModulePassRunCount = 0;
MPM.addPass(TestModulePass(ModulePassRunCount));
// Count the runs over a Function.
int FunctionPassRunCount = 0;
int AnalyzedInstrCount = 0;
FPM.addPass(TestFunctionPass(AM, FunctionPassRunCount, AnalyzedInstrCount));
MPM.addPass(FPM);
MPM.run();
EXPECT_EQ(1, ModulePassRunCount);
EXPECT_EQ(3, FunctionPassRunCount);
EXPECT_EQ(5, AnalyzedInstrCount);
}
}