forked from OSchip/llvm-project
195 lines
6.9 KiB
C++
195 lines
6.9 KiB
C++
//===- Optimize.cpp - Optimize a complete program -------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file was developed by Reid Spencer and is distributed under the
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// University of Illinois Open Source License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements all optimization of the linked module for llvm-ld.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Module.h"
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#include "llvm/PassManager.h"
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#include "llvm/Analysis/LoadValueNumbering.h"
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#include "llvm/Analysis/Passes.h"
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#include "llvm/Analysis/Verifier.h"
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#include "llvm/Support/CommandLine.h"
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#include "llvm/System/DynamicLibrary.h"
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#include "llvm/Target/TargetData.h"
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#include "llvm/Transforms/IPO.h"
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#include "llvm/Transforms/Scalar.h"
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using namespace llvm;
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// Optimization Options
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enum OptimizationLevels {
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OPT_FAST_COMPILE = 1,
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OPT_SIMPLE = 2,
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OPT_AGGRESSIVE = 3,
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OPT_LINK_TIME = 4,
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OPT_AGGRESSIVE_LINK_TIME = 5
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};
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static cl::opt<OptimizationLevels> OptLevel(
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cl::desc("Choose level of optimization to apply:"),
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cl::init(OPT_FAST_COMPILE), cl::values(
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clEnumValN(OPT_FAST_COMPILE,"O0",
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"An alias for the -O1 option."),
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clEnumValN(OPT_FAST_COMPILE,"O1",
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"Optimize for linking speed, not execution speed."),
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clEnumValN(OPT_SIMPLE,"O2",
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"Perform only required/minimal optimizations"),
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clEnumValN(OPT_AGGRESSIVE,"O3",
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"An alias for the -O2 option."),
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clEnumValN(OPT_LINK_TIME,"O4",
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"Perform standard link time optimizations"),
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clEnumValN(OPT_AGGRESSIVE_LINK_TIME,"O5",
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"Perform aggressive link time optimizations"),
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clEnumValEnd
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)
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);
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static cl::opt<bool> DisableInline("disable-inlining",
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cl::desc("Do not run the inliner pass"));
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static cl::opt<bool>
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DisableOptimizations("disable-opt",
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cl::desc("Do not run any optimization passes"));
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static cl::opt<bool> DisableInternalize("disable-internalize",
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cl::desc("Do not mark all symbols as internal"));
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static cl::opt<bool> Verify("verify",
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cl::desc("Verify intermediate results of all passes"));
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static cl::opt<bool> Strip("s",
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cl::desc("Strip symbol info from executable"));
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static cl::alias ExportDynamic("export-dynamic",
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cl::aliasopt(DisableInternalize),
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cl::desc("Alias for -disable-internalize"));
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static cl::list<std::string> LoadableModules("load",
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cl::value_desc("path to loadable optimization module"),
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cl::desc("Load an optimization module and run it"));
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// A utility function that adds a pass to the pass manager but will also add
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// a verifier pass after if we're supposed to verify.
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static inline void addPass(PassManager &PM, Pass *P) {
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// Add the pass to the pass manager...
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PM.add(P);
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// If we are verifying all of the intermediate steps, add the verifier...
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if (Verify)
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PM.add(createVerifierPass());
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}
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namespace llvm {
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/// Optimize - Perform link time optimizations. This will run the scalar
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/// optimizations, any loaded plugin-optimization modules, and then the
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/// inter-procedural optimizations if applicable.
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void Optimize(Module* M) {
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// Instantiate the pass manager to organize the passes.
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PassManager Passes;
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// If we're verifying, start off with a verification pass.
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if (Verify)
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Passes.add(createVerifierPass());
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// Add an appropriate TargetData instance for this module...
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addPass(Passes, new TargetData("gccld", M));
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// Often if the programmer does not specify proper prototypes for the
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// functions they are calling, they end up calling a vararg version of the
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// function that does not get a body filled in (the real function has typed
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// arguments). This pass merges the two functions.
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addPass(Passes, createFunctionResolvingPass());
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if (!DisableOptimizations) {
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if (!DisableInternalize) {
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// Now that composite has been compiled, scan through the module, looking
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// for a main function. If main is defined, mark all other functions
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// internal.
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addPass(Passes, createInternalizePass());
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}
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// Now that we internalized some globals, see if we can hack on them!
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addPass(Passes, createGlobalOptimizerPass());
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// Linking modules together can lead to duplicated global constants, only
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// keep one copy of each constant...
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addPass(Passes, createConstantMergePass());
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// If the -s command line option was specified, strip the symbols out of the
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// resulting program to make it smaller. -s is a GLD option that we are
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// supporting.
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if (Strip)
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addPass(Passes, createStripSymbolsPass());
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// Propagate constants at call sites into the functions they call.
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addPass(Passes, createIPConstantPropagationPass());
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// Remove unused arguments from functions...
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addPass(Passes, createDeadArgEliminationPass());
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if (!DisableInline)
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addPass(Passes, createFunctionInliningPass()); // Inline small functions
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addPass(Passes, createPruneEHPass()); // Remove dead EH info
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addPass(Passes, createGlobalDCEPass()); // Remove dead functions
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// If we didn't decide to inline a function, check to see if we can
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// transform it to pass arguments by value instead of by reference.
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addPass(Passes, createArgumentPromotionPass());
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// The IPO passes may leave cruft around. Clean up after them.
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addPass(Passes, createInstructionCombiningPass());
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addPass(Passes, createScalarReplAggregatesPass()); // Break up allocas
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// Run a few AA driven optimizations here and now, to cleanup the code.
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addPass(Passes, createGlobalsModRefPass()); // IP alias analysis
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addPass(Passes, createLICMPass()); // Hoist loop invariants
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addPass(Passes, createLoadValueNumberingPass()); // GVN for load instrs
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addPass(Passes, createGCSEPass()); // Remove common subexprs
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addPass(Passes, createDeadStoreEliminationPass()); // Nuke dead stores
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// Cleanup and simplify the code after the scalar optimizations.
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addPass(Passes, createInstructionCombiningPass());
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// Delete basic blocks, which optimization passes may have killed...
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addPass(Passes, createCFGSimplificationPass());
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// Now that we have optimized the program, discard unreachable functions...
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addPass(Passes, createGlobalDCEPass());
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}
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std::vector<std::string> plugins = LoadableModules;
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for (std::vector<std::string>::iterator I = plugins.begin(),
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E = plugins.end(); I != E; ++I) {
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sys::DynamicLibrary dll(I->c_str());
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typedef void (*OptimizeFunc)(PassManager&,int);
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OptimizeFunc OF = OptimizeFunc(
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dll.GetAddressOfSymbol("RunOptimizations"));
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if (OF == 0) {
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throw std::string("Optimization Module '") + *I +
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"' is missing the RunOptimizations symbol";
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}
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(*OF)(Passes,OptLevel);
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}
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// Make sure everything is still good.
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Passes.add(createVerifierPass());
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// Run our queue of passes all at once now, efficiently.
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Passes.run(*M);
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}
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}
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