[llvm-commits] CVS: llvm/tools/llvm-ld/Optimize.cpp

[Reid Spencer]

Changes in directory llvm/tools/llvm-ld:

Optimize.cpp added (r1.1)
---
Log message:

First cut at implementing generic link-time Optimization

---
Diffs of the changes:  (+194 -0)

Index: llvm/tools/llvm-ld/Optimize.cpp
diff -c /dev/null llvm/tools/llvm-ld/Optimize.cpp:1.1
*** /dev/null	Sat Nov 20 13:49:39 2004
--- llvm/tools/llvm-ld/Optimize.cpp	Sat Nov 20 13:43:28 2004
***************
*** 0 ****
--- 1,194 ----
+ //===- 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/Verifier.h"
+ #include "llvm/Support/CommandLine.h"
+ #include "llvm/System/DynamicLibrary.h"
+ #include "llvm/Target/TargetData.h"
+ #include "llvm/Transforms/IPO.h"
+ #include "llvm/Transforms/Scalar.h"
+ using namespace llvm;
+ 
+ // Optimization Options
+ 
+ enum OptimizationLevels {
+   OPT_FAST_COMPILE         = 1,
+   OPT_SIMPLE               = 2,
+   OPT_AGGRESSIVE           = 3,
+   OPT_LINK_TIME            = 4,
+   OPT_AGGRESSIVE_LINK_TIME = 5
+ };
+ 
+ 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> Verify("verify", 
+   cl::desc("Verify intermediate results of all passes"));
+ 
+ static cl::opt<bool> Strip("s", 
+   cl::desc("Strip symbol info from executable"));
+ 
+ static cl::alias ExportDynamic("export-dynamic", 
+   cl::aliasopt(DisableInternalize),
+   cl::desc("Alias for -disable-internalize"));
+ 
+ static cl::list<std::string> LoadableModules("load",
+   cl::value_desc("path to loadable optimization module"),
+   cl::desc("Load an optimization module and run it"));
+ 
+ // 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 (Verify) 
+     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 (Verify) 
+     Passes.add(createVerifierPass());
+ 
+   // Add an appropriate TargetData instance for this module...
+   addPass(Passes, new TargetData("gccld", M));
+ 
+   // Often if the programmer does not specify proper prototypes for the
+   // functions they are calling, they end up calling a vararg version of the
+   // function that does not get a body filled in (the real function has typed
+   // arguments).  This pass merges the two functions.
+   addPass(Passes, createFunctionResolvingPass());
+ 
+   if (!DisableOptimizations) {
+     if (!DisableInternalize) {
+       // Now that composite has been compiled, scan through the module, looking
+       // for a main function.  If main is defined, mark all other functions
+       // internal.
+       addPass(Passes, createInternalizePass());
+     }
+ 
+     // 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());
+ 
+     // If the -s command line option was specified, strip the symbols out of the
+     // resulting program to make it smaller.  -s is a GCC option that we are
+     // supporting.
+     if (Strip)
+       addPass(Passes, createSymbolStrippingPass());
+ 
+     // Propagate constants at call sites into the functions they call.
+     addPass(Passes, createIPConstantPropagationPass());
+ 
+     // Remove unused arguments from functions...
+     addPass(Passes, createDeadArgEliminationPass());
+ 
+     if (!DisableInline)
+       addPass(Passes, createFunctionInliningPass()); // Inline small functions
+ 
+     addPass(Passes, createPruneEHPass());            // Remove dead EH info
+     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, createDeadStoreEliminationPass()); // 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());
+   }
+ 
+   std::vector<std::string> plugins = LoadableModules;
+   for (std::vector<std::string>::iterator I = plugins.begin(), 
+       E = plugins.end(); I != E; ++I) {
+     sys::DynamicLibrary dll(I->c_str());
+     typedef void (*OptimizeFunc)(PassManager&,int);
+     OptimizeFunc OF = OptimizeFunc(
+         dll.GetAddressOfSymbol("RunOptimizations"));
+     if (OF == 0) {
+       throw std::string("Optimization Module '") + *I + 
+         "' is missing the RunOptimizations symbol";
+     }
+     (*OF)(Passes,OptLevel);
+   }
+ 
+   // Make sure everything is still good.
+   Passes.add(createVerifierPass());
+ 
+   // Run our queue of passes all at once now, efficiently.
+   Passes.run(*M);
+ }
+ 
+ }