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+//===- Optimize.cpp - Optimize a complete program -------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Reid Spencer and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements all optimization of the linked module for llvm-ld.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Module.h"
+#include "llvm/PassManager.h"
+#include "llvm/Analysis/LoadValueNumbering.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/Verifier.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/System/DynamicLibrary.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Support/PassNameParser.h"
+#include "llvm/Support/PluginLoader.h"
+#include <iostream>
+using namespace llvm;
+
+// Pass Name Options as generated by the PassNameParser
+static cl::list<const PassInfo*, bool, PassNameParser>
+ OptimizationList(cl::desc("Optimizations available:"));
+
+// Optimization Enumeration
+enum OptimizationLevels {
+ OPT_FAST_COMPILE = 1,
+ OPT_SIMPLE = 2,
+ OPT_AGGRESSIVE = 3,
+ OPT_LINK_TIME = 4,
+ OPT_AGGRESSIVE_LINK_TIME = 5
+};
+
+// Optimization Options
+static cl::opt<OptimizationLevels> OptLevel(
+ cl::desc("Choose level of optimization to apply:"),
+ cl::init(OPT_FAST_COMPILE), cl::values(
+ clEnumValN(OPT_FAST_COMPILE,"O0",
+ "An alias for the -O1 option."),
+ clEnumValN(OPT_FAST_COMPILE,"O1",
+ "Optimize for linking speed, not execution speed."),
+ clEnumValN(OPT_SIMPLE,"O2",
+ "Perform only required/minimal optimizations"),
+ clEnumValN(OPT_AGGRESSIVE,"O3",
+ "An alias for the -O2 option."),
+ clEnumValN(OPT_LINK_TIME,"O4",
+ "Perform standard link time optimizations"),
+ clEnumValN(OPT_AGGRESSIVE_LINK_TIME,"O5",
+ "Perform aggressive link time optimizations"),
+ clEnumValEnd
+ )
+);
+
+static cl::opt<bool> DisableInline("disable-inlining",
+ cl::desc("Do not run the inliner pass"));
+
+static cl::opt<bool>
+DisableOptimizations("disable-opt",
+ cl::desc("Do not run any optimization passes"));
+
+static cl::opt<bool> DisableInternalize("disable-internalize",
+ cl::desc("Do not mark all symbols as internal"));
+
+static cl::opt<bool> VerifyEach("verify-each",
+ cl::desc("Verify intermediate results of all passes"));
+
+static cl::alias ExportDynamic("export-dynamic",
+ cl::aliasopt(DisableInternalize),
+ cl::desc("Alias for -disable-internalize"));
+
+static cl::opt<bool> Strip("strip-all",
+ cl::desc("Strip all symbol info from executable"));
+
+static cl::alias A0("s", cl::desc("Alias for --strip-all"),
+ cl::aliasopt(Strip));
+
+static cl::opt<bool> StripDebug("strip-debug",
+ cl::desc("Strip debugger symbol info from executable"));
+
+static cl::alias A1("S", cl::desc("Alias for --strip-debug"),
+ cl::aliasopt(StripDebug));
+
+// A utility function that adds a pass to the pass manager but will also add
+// a verifier pass after if we're supposed to verify.
+static inline void addPass(PassManager &PM, Pass *P) {
+ // Add the pass to the pass manager...
+ PM.add(P);
+
+ // If we are verifying all of the intermediate steps, add the verifier...
+ if (VerifyEach)
+ PM.add(createVerifierPass());
+}
+
+namespace llvm {
+
+/// Optimize - Perform link time optimizations. This will run the scalar
+/// optimizations, any loaded plugin-optimization modules, and then the
+/// inter-procedural optimizations if applicable.
+void Optimize(Module* M) {
+
+ // Instantiate the pass manager to organize the passes.
+ PassManager Passes;
+
+ // If we're verifying, start off with a verification pass.
+ if (VerifyEach)
+ Passes.add(createVerifierPass());
+
+ // Add an appropriate TargetData instance for this module...
+ addPass(Passes, new TargetData(M));
+
+ if (!DisableOptimizations) {
+ // Now that composite has been compiled, scan through the module, looking
+ // for a main function. If main is defined, mark all other functions
+ // internal.
+ if (!DisableInternalize)
+ addPass(Passes, createInternalizePass(true));
+
+ // Propagate constants at call sites into the functions they call. This
+ // opens opportunities for globalopt (and inlining) by substituting function
+ // pointers passed as arguments to direct uses of functions.
+ addPass(Passes, createIPSCCPPass());
+
+ // Now that we internalized some globals, see if we can hack on them!
+ addPass(Passes, createGlobalOptimizerPass());
+
+ // Linking modules together can lead to duplicated global constants, only
+ // keep one copy of each constant...
+ addPass(Passes, createConstantMergePass());
+
+ // Remove unused arguments from functions...
+ addPass(Passes, createDeadArgEliminationPass());
+
+ // Reduce the code after globalopt and ipsccp. Both can open up significant
+ // simplification opportunities, and both can propagate functions through
+ // function pointers. When this happens, we often have to resolve varargs
+ // calls, etc, so let instcombine do this.
+ addPass(Passes, createInstructionCombiningPass());
+
+ if (!DisableInline)
+ addPass(Passes, createFunctionInliningPass()); // Inline small functions
+
+ addPass(Passes, createPruneEHPass()); // Remove dead EH info
+ addPass(Passes, createGlobalOptimizerPass()); // Optimize globals again.
+ addPass(Passes, createGlobalDCEPass()); // Remove dead functions
+
+ // If we didn't decide to inline a function, check to see if we can
+ // transform it to pass arguments by value instead of by reference.
+ addPass(Passes, createArgumentPromotionPass());
+
+ // The IPO passes may leave cruft around. Clean up after them.
+ addPass(Passes, createInstructionCombiningPass());
+
+ addPass(Passes, createScalarReplAggregatesPass()); // Break up allocas
+
+ // Run a few AA driven optimizations here and now, to cleanup the code.
+ addPass(Passes, createGlobalsModRefPass()); // IP alias analysis
+
+ addPass(Passes, createLICMPass()); // Hoist loop invariants
+ addPass(Passes, createLoadValueNumberingPass()); // GVN for load instrs
+ addPass(Passes, createGCSEPass()); // Remove common subexprs
+ addPass(Passes, createFastDeadStoreEliminationPass()); // Nuke dead stores
+
+ // Cleanup and simplify the code after the scalar optimizations.
+ addPass(Passes, createInstructionCombiningPass());
+
+ // Delete basic blocks, which optimization passes may have killed...
+ addPass(Passes, createCFGSimplificationPass());
+
+ // Now that we have optimized the program, discard unreachable functions...
+ addPass(Passes, createGlobalDCEPass());
+ }
+
+ // If the -s or -S command line options were specified, strip the symbols out
+ // of the resulting program to make it smaller. -s and -S are GNU ld options
+ // that we are supporting; they alias -strip-all and -strip-debug.
+ if (Strip || StripDebug)
+ addPass(Passes, createStripSymbolsPass(StripDebug && !Strip));
+
+ // Create a new optimization pass for each one specified on the command line
+ std::auto_ptr<TargetMachine> target;
+ for (unsigned i = 0; i < OptimizationList.size(); ++i) {
+ const PassInfo *Opt = OptimizationList[i];
+ if (Opt->getNormalCtor())
+ addPass(Passes, Opt->getNormalCtor()());
+ else
+ std::cerr << "llvm-ld: cannot create pass: " << Opt->getPassName()
+ << "\n";
+ }
+
+ // The user's passes may leave cruft around. Clean up after them them but
+ // only if we haven't got DisableOptimizations set
+ if (!DisableOptimizations) {
+ addPass(Passes, createInstructionCombiningPass());
+ addPass(Passes, createCFGSimplificationPass());
+ addPass(Passes, createDeadCodeEliminationPass());
+ addPass(Passes, createGlobalDCEPass());
+ }
+
+ // Make sure everything is still good.
+ Passes.add(createVerifierPass());
+
+ // Run our queue of passes all at once now, efficiently.
+ Passes.run(*M);
+}
+
+}