From 1bffea0341968b3b2b0106c745d4602b6804e62f Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Mon, 15 Oct 2001 17:31:51 +0000 Subject: [PATCH] Add new Pass infrastructure and some examples git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@836 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Transforms/ChangeAllocations.h | 39 ++++ include/llvm/Transforms/HoistPHIConstants.h | 20 ++ include/llvm/Transforms/Pass.h | 200 ++++++++++++++++++++ include/llvm/Transforms/PrintModulePass.h | 35 ++++ lib/Transforms/HoistPHIConstants.cpp | 61 ++++++ lib/Transforms/Utils/LowerAllocations.cpp | 121 ++++++++++++ 6 files changed, 476 insertions(+) create mode 100644 include/llvm/Transforms/ChangeAllocations.h create mode 100644 include/llvm/Transforms/HoistPHIConstants.h create mode 100644 include/llvm/Transforms/Pass.h create mode 100644 include/llvm/Transforms/PrintModulePass.h create mode 100644 lib/Transforms/HoistPHIConstants.cpp create mode 100644 lib/Transforms/Utils/LowerAllocations.cpp diff --git a/include/llvm/Transforms/ChangeAllocations.h b/include/llvm/Transforms/ChangeAllocations.h new file mode 100644 index 00000000000..08339cd64e8 --- /dev/null +++ b/include/llvm/Transforms/ChangeAllocations.h @@ -0,0 +1,39 @@ +//===- llvm/Transforms/LowerAllocations.h - Remove Malloc & Free -*- C++ -*--=// +// +// This file defines the interface to a pass that lowers malloc and free +// instructions to calls to %malloc & %free functions. This transformation is +// a target dependant tranformation because we depend on the size of data types +// and alignment constraints. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_LOWERALLOCATIONS_H +#define LLVM_TRANSFORMS_LOWERALLOCATIONS_H + +#include "llvm/Transforms/Pass.h" +class TargetData; + +class LowerAllocations : public ConcretePass { + Method *MallocMeth; // Methods in the module we are processing + Method *FreeMeth; // Initialized by doPassInitializationVirt + + const TargetData &DataLayout; +public: + inline LowerAllocations(const TargetData &TD) : DataLayout(TD) { + MallocMeth = FreeMeth = 0; + } + + // doPassInitialization - For the lower allocations pass, this ensures that a + // module contains a declaration for a malloc and a free function. + // + // This function is always successful. + // + bool doPassInitializationVirt(Module *M); + + // doPerMethodWork - This method does the actual work of converting + // instructions over, assuming that the pass has already been initialized. + // + bool doPerMethodWorkVirt(Method *M); +}; + +#endif diff --git a/include/llvm/Transforms/HoistPHIConstants.h b/include/llvm/Transforms/HoistPHIConstants.h new file mode 100644 index 00000000000..d15ead91f43 --- /dev/null +++ b/include/llvm/Transforms/HoistPHIConstants.h @@ -0,0 +1,20 @@ +//===- llvm/Transforms/HoistPHIConstants.h - Normalize PHI nodes -*- C++ -*--=// +// +// HoistPHIConstants - Remove literal constants that are arguments of PHI nodes +// by inserting cast instructions in the preceeding basic blocks, and changing +// constant references into references of the casted value. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_HOISTPHICONSTANTS_H +#define LLVM_TRANSFORMS_HOISTPHICONSTANTS_H + +#include "llvm/Transforms/Pass.h" + +struct HoistPHIConstants : public StatelessPass { + // doPerMethodWork - This method does the work. Always successful. + // + static bool doPerMethodWork(Method *M); +}; + +#endif diff --git a/include/llvm/Transforms/Pass.h b/include/llvm/Transforms/Pass.h new file mode 100644 index 00000000000..c6ba84ec5d0 --- /dev/null +++ b/include/llvm/Transforms/Pass.h @@ -0,0 +1,200 @@ +//===- llvm/Transforms/Pass.h - Base class for XForm Passes ------*- C++ -*--=// +// +// This file defines a marker class that indicates that a specified class is a +// transformation pass implementation. +// +// Pass's are designed this way so that it is possible to apply N passes to a +// module, by first doing N Pass specific initializations for the module, then +// looping over all of the methods in the module, doing method specific work +// N times for each method. Like this: +// +// for_each(Passes.begin(), Passes.end(), doPassInitialization(Module)); +// for_each(Method *M <- Module->begin(), Module->end()) +// for_each(Passes.begin(), Passes.end(), doPerMethodWork(M)); +// +// The other way to do things is like this: +// for_each(Pass *P <- Passes.begin(), Passes.end()) { +// Passes->doPassInitialization(Module) +// for_each(Module->begin(), Module->end(), P->doPerMethodWork); +// } +// +// But this can cause thrashing and poor cache performance, so we don't do it +// that way. +// +// Because a transformation does not see all methods consecutively, it should +// be careful about the state that it maintains... another pass may modify a +// method between two invokacations of doPerMethodWork. +// +// Also, implementations of doMethodWork should not remove any methods from the +// module. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_PASS_H +#define LLVM_TRANSFORMS_PASS_H + +#include "llvm/Module.h" +#include "llvm/Method.h" + +//===----------------------------------------------------------------------===// +// Pass interface - Implemented by all 'passes'. +// +struct Pass { + //===--------------------------------------------------------------------===// + // The externally useful entry points + // + + // runAllPasses - Run a bunch of passes on the specified module, efficiently. + static bool runAllPasses(Module *M, vector &Passes) { + for (unsigned i = 0; i < Passes.size(); ++i) + if (Passes[i]->doPassInitializationVirt(M)) return true; + + // Loop over all of the methods, applying all of the passes to them + for (Module::iterator I = M->begin(); I != M->end(); ++I) + for (unsigned i = 0; i < Passes.size(); ++i) + if (Passes[i]->doPerMethodWorkVirt(*I)) return true; + return false; + } + + // runAllPassesAndFree - Run a bunch of passes on the specified module, + // efficiently. When done, delete all of the passes. + // + static bool runAllPassesAndFree(Module *M, vector &Passes) { + // First run all of the passes + bool Result = runAllPasses(M, Passes); + + // Free all of the passes. + for (unsigned i = 0; i < Passes.size(); ++i) + delete Passes[i]; + return Result; + } + + + // run(Module*) - Run this pass on a module and all of the methods contained + // within it. Returns false on success. + // + bool run(Module *M) { + if (doPassInitializationVirt(M)) return true; + + // Loop over methods in the module. doPerMethodWork could add a method to + // the Module, so we have to keep checking for end of method list condition. + // + for (Module::iterator I = M->begin(); I != M->end(); ++I) + if (doPerMethodWorkVirt(*I)) return true; + return false; + } + + // run(Method*) - Run this pass on a module and one specific method. Returns + // false on success. + // + bool run(Method *M) { + if (doPassInitializationVirt(M->getParent())) return true; + return doPerMethodWorkVirt(M); + } + + + //===--------------------------------------------------------------------===// + // Functions to be implemented by subclasses + // + + // Destructor - Virtual so we can be subclassed + inline virtual ~Pass() {} + + // doPassInitializationVirt - Virtual method overridden by subclasses to do + // any neccesary per-module initialization. Returns false on success. + // + virtual bool doPassInitializationVirt(Module *M) = 0; + + // doPerMethodWorkVirt - Virtual method overriden by subclasses to do the + // per-method processing of the pass. Returns false on success. + // + virtual bool doPerMethodWorkVirt(Method *M) = 0; +}; + + +//===----------------------------------------------------------------------===// +// ConcretePass class - This is used by implementations of passes to fill in +// boiler plate code. SubClass should be a concrete class that is derived from +// ConcretePass. +// +// Deriving from this class is good because if new methods are added in the +// future, code for your pass won't have to change to stub out the unused +// functionality. +// +template +struct ConcretePass : public Pass { + + // doPassInitializationVirt - Default to success. + virtual bool doPassInitializationVirt(Module *M) { return false; } + + // doPerMethodWorkVirt - Default to success. + virtual bool doPerMethodWorkVirt(Method *M) { return false; } +}; + + + +//===----------------------------------------------------------------------===// +// StatelessPass class - This is used by implementations of passes to fill in +// boiler plate code. Subclassing this class indicates that a class has no +// state to keep around, so it's safe to invoke static versions of functions. +// This can be more efficient that using virtual function dispatch all of the +// time. +// +// SubClass should be a concrete class that is derived from StatelessPass. +// +template +struct StatelessPass : public ConcretePass { + + //===--------------------------------------------------------------------===// + // The externally useful entry points - These are specialized to avoid the + // overhead of virtual method invokations if + // + // run(Module*) - Run this pass on a module and all of the methods contained + // within it. Returns false on success. + // + static bool run(Module *M) { + if (doPassInitialization(M->getParent())) return true; + + // Loop over methods in the module. doPerMethodWork could add a method to + // the Module, so we have to keep checking for end of method list condition. + // + for (Module::iterator I = M->begin(); I != M->end(); ++I) + if (doPerMethodWork(*I)) return true; + return false; + } + + // run(Method*) - Run this pass on a module and one specific method. Returns + // false on success. + // + static bool run(Method *M) { + if (doPassInitialization(M->getParent())) return true; + return doPerMethodWork(M); + } + + //===--------------------------------------------------------------------===// + // Default static method implementations, these should be defined in SubClass + + static bool doPassInitialization(Module *M) { return false; } + static bool doPerMethodWork(Method *M) { return false; } + + + //===--------------------------------------------------------------------===// + // Virtual method forwarders... + + // doPassInitializationVirt - For a StatelessPass, default to implementing in + // terms of the static method. + // + virtual bool doPassInitializationVirt(Module *M) { + return SubClass::doPassInitialization(M); + } + + // doPerMethodWorkVirt - For a StatelessPass, default to implementing in + // terms of the static method. + // + virtual bool doPerMethodWorkVirt(Method *M) { + return SubClass::doPerMethodWork(M); + } +}; + +#endif + diff --git a/include/llvm/Transforms/PrintModulePass.h b/include/llvm/Transforms/PrintModulePass.h new file mode 100644 index 00000000000..90cd369f7b6 --- /dev/null +++ b/include/llvm/Transforms/PrintModulePass.h @@ -0,0 +1,35 @@ +//===- llvm/Transforms/PrintModulePass.h - Printing Pass ---------*- C++ -*--=// +// +// This file defines a simple pass to print out methods of a module as they are +// processed. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_TRANSFORMS_PRINTMODULE_H +#define LLVM_TRANSFORMS_PRINTMODULE_H + +#include "llvm/Transforms/Pass.h" +#include "llvm/Assembly/Writer.h" + +class PrintModulePass : public ConcretePass { + string Banner; // String to print before each method + ostream *Out; // ostream to print on + bool DeleteStream; // Delete the ostream in our dtor? +public: + inline PrintModulePass(const string &B, ostream *o = &cout, bool DS = false) + : Banner(B), Out(o), DeleteStream(DS) {} + + ~PrintModulePass() { + if (DeleteStream) delete Out; + } + + // doPerMethodWork - This pass just prints a banner followed by the method as + // it's processed. + // + bool doPerMethodWorkVirt(Method *M) { + (*Out) << Banner << M; + return false; + } +}; + +#endif diff --git a/lib/Transforms/HoistPHIConstants.cpp b/lib/Transforms/HoistPHIConstants.cpp new file mode 100644 index 00000000000..de806fc4098 --- /dev/null +++ b/lib/Transforms/HoistPHIConstants.cpp @@ -0,0 +1,61 @@ +//===- llvm/Transforms/HoistPHIConstants.h - Normalize PHI nodes ------------=// +// +// HoistPHIConstants - Remove literal constants that are arguments of PHI nodes +// by inserting cast instructions in the preceeding basic blocks, and changing +// constant references into references of the casted value. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Transforms/HoistPHIConstants.h" +#include "llvm/iOther.h" +#include "llvm/BasicBlock.h" +#include "llvm/Method.h" +#include + +typedef pair BBConstTy; +typedef map CachedCopyMap; + +static Value *NormalizePhiOperand(PHINode *PN, Value *CPV, + BasicBlock *Pred, CachedCopyMap &CopyCache) { + + // Check if we've already inserted a copy for this constant in Pred + // Note that `copyCache[Pred]' will create an empty vector the first time + // + CachedCopyMap::iterator CCI = CopyCache.find(BBConstTy(Pred, CPV)); + if (CCI != CopyCache.end()) return CCI->second; + + // Create a copy instruction and add it to the cache... + CastInst *Inst = new CastInst(CPV, CPV->getType()); + CopyCache.insert(make_pair(BBConstTy(Pred, CPV), Inst)); + + // Insert the copy just before the terminator inst of the predecessor BB + assert(Pred->getTerminator() && "Degenerate BB encountered!"); + Pred->getInstList().insert(Pred->getInstList().end()-1, Inst); + + return Inst; +} + + +//--------------------------------------------------------------------------- +// Entry point for normalizing constant args in PHIs +//--------------------------------------------------------------------------- + +bool HoistPHIConstants::doPerMethodWork(Method *M) { + CachedCopyMap Cache; + + for (Method::iterator BI = M->begin(), BE = M->end(); BI != BE; ++BI) + for (BasicBlock::iterator II = (*BI)->begin(); II != (*BI)->end(); ++II) { + Instruction *Inst = *II; + if (!isa(Inst)) break; // All PHIs occur at top of BB! + + PHINode *PN = cast(Inst); + for (unsigned i = 0; i < PN->getNumIncomingValues(); ++i) { + Value *Op = PN->getIncomingValue(i); + if (isa(Op)) + PN->setIncomingValue(i, + NormalizePhiOperand(PN, Op, PN->getIncomingBlock(i), Cache)); + } + } + + return false; +} diff --git a/lib/Transforms/Utils/LowerAllocations.cpp b/lib/Transforms/Utils/LowerAllocations.cpp new file mode 100644 index 00000000000..ba78ce18fd5 --- /dev/null +++ b/lib/Transforms/Utils/LowerAllocations.cpp @@ -0,0 +1,121 @@ +//===- llvm/Transforms/LowerAllocations.h - Remove Malloc & Free Insts ------=// +// +// This file implements a pass that lowers malloc and free instructions to +// calls to %malloc & %free functions. This transformation is a target +// dependant tranformation because we depend on the size of data types and +// alignment constraints. +// +//===----------------------------------------------------------------------===// + +#include "llvm/Transforms/LowerAllocations.h" +#include "llvm/Target/TargetData.h" +#include "llvm/DerivedTypes.h" +#include "llvm/iMemory.h" +#include "llvm/iOther.h" +#include "llvm/SymbolTable.h" + +// doPassInitialization - For the lower allocations pass, this ensures that a +// module contains a declaration for a malloc and a free function. +// +// This function is always successful. +// +bool LowerAllocations::doPassInitializationVirt(Module *M) { + const MethodType *MallocType = + MethodType::get(PointerType::get(Type::UByteTy), + vector(1, Type::UIntTy), false); + + SymbolTable *SymTab = M->getSymbolTableSure(); + + // Check for a definition of malloc + if (Value *V = SymTab->lookup(PointerType::get(MallocType), "malloc")) { + MallocMeth = cast(V); // Yup, got it + } else { // Nope, add one + M->getMethodList().push_back(MallocMeth = new Method(MallocType, "malloc")); + } + + const MethodType *FreeType = + MethodType::get(Type::VoidTy, + vector(1, PointerType::get(Type::UByteTy)), + false); + + // Check for a definition of free + if (Value *V = SymTab->lookup(PointerType::get(FreeType), "free")) { + FreeMeth = cast(V); // Yup, got it + } else { // Nope, add one + M->getMethodList().push_back(FreeMeth = new Method(FreeType, "free")); + } + + return false; // Always successful +} + +// doPerMethodWork - This method does the actual work of converting +// instructions over, assuming that the pass has already been initialized. +// +bool LowerAllocations::doPerMethodWorkVirt(Method *M) { + assert(MallocMeth && FreeMeth && M && "Pass not initialized!"); + + // Loop over all of the instructions, looking for malloc or free instructions + for (Method::iterator BBI = M->begin(), BBE = M->end(); BBI != BBE; ++BBI) { + BasicBlock *BB = *BBI; + for (unsigned i = 0; i < BB->size(); ++i) { + BasicBlock::InstListType &BBIL = BB->getInstList(); + if (MallocInst *MI = dyn_cast(*(BBIL.begin()+i))) { + BBIL.remove(BBIL.begin()+i); // remove the malloc instr... + + const Type *AllocTy = cast(MI->getType())->getValueType(); + + // If the user is allocating an unsized array with a dynamic size arg, + // start by getting the size of one element. + // + if (const ArrayType *ATy = dyn_cast(AllocTy)) + if (ATy->isUnsized()) AllocTy = ATy->getElementType(); + + // Get the number of bytes to be allocated for one element of the + // requested type... + unsigned Size = DataLayout.getTypeSize(AllocTy); + + // malloc(type) becomes sbyte *malloc(constint) + Value *MallocArg = ConstPoolUInt::get(Type::UIntTy, Size); + if (MI->getNumOperands() && Size == 1) { + MallocArg = MI->getOperand(0); // Operand * 1 = Operand + } else if (MI->getNumOperands()) { + // Multiply it by the array size if neccesary... + MallocArg = BinaryOperator::create(Instruction::Mul,MI->getOperand(0), + MallocArg); + BBIL.insert(BBIL.begin()+i++, cast(MallocArg)); + } + + // Create the call to Malloc... + CallInst *MCall = new CallInst(MallocMeth, + vector(1, MallocArg)); + BBIL.insert(BBIL.begin()+i, MCall); + + // Create a cast instruction to convert to the right type... + CastInst *MCast = new CastInst(MCall, MI->getType()); + BBIL.insert(BBIL.begin()+i+1, MCast); + + // Replace all uses of the old malloc inst with the cast inst + MI->replaceAllUsesWith(MCast); + delete MI; // Delete the malloc inst + } else if (FreeInst *FI = dyn_cast(*(BBIL.begin()+i))) { + BBIL.remove(BB->getInstList().begin()+i); + + // Cast the argument to free into a ubyte*... + CastInst *MCast = new CastInst(FI->getOperand(0), + PointerType::get(Type::UByteTy)); + BBIL.insert(BBIL.begin()+i, MCast); + + // Insert a call to the free function... + CallInst *FCall = new CallInst(FreeMeth, + vector(1, MCast)); + BBIL.insert(BBIL.begin()+i+1, FCall); + + // Delete the old free instruction + delete FI; + } + } + } + + return false; // Always successful +} +