1 //===----------------------------------------------------------------------===//
2 // LLVM 'GCCAS' UTILITY
4 // This utility is designed to be used by the GCC frontend for creating
5 // bytecode files from it's intermediate llvm assembly. The requirements for
6 // this utility are thus slightly different than that of the standard as util.
8 //===----------------------------------------------------------------------===//
10 #include "llvm/Module.h"
11 #include "llvm/PassManager.h"
12 #include "llvm/Assembly/Parser.h"
13 #include "llvm/Transforms/RaisePointerReferences.h"
14 #include "llvm/Transforms/IPO.h"
15 #include "llvm/Transforms/Scalar.h"
16 #include "llvm/Analysis/LoadValueNumbering.h"
17 #include "llvm/Analysis/Verifier.h"
18 #include "llvm/Bytecode/WriteBytecodePass.h"
19 #include "llvm/Target/TargetData.h"
20 #include "Support/CommandLine.h"
21 #include "Support/Signals.h"
26 // FIXME: This should eventually be parameterized...
27 static TargetData TD("opt target");
29 static cl::opt<std::string>
30 InputFilename(cl::Positional, cl::desc("<input llvm assembly>"), cl::Required);
32 static cl::opt<std::string>
33 OutputFilename("o", cl::desc("Override output filename"),
34 cl::value_desc("filename"));
37 RunNPasses("stopAfterNPasses",
38 cl::desc("Only run the first N passes of gccas"), cl::Hidden,
39 cl::value_desc("# passes"));
42 StopAtLevelRaise("stopraise", cl::desc("Stop optimization before level raise"),
46 Verify("verify", cl::desc("Verify each pass result"));
49 static inline void addPass(PassManager &PM, Pass *P) {
50 static int NumPassesCreated = 0;
52 // If we haven't already created the number of passes that was requested...
53 if (RunNPasses == 0 || RunNPasses > NumPassesCreated) {
54 // Add the pass to the pass manager...
57 // If we are verifying all of the intermediate steps, add the verifier...
58 if (Verify) PM.add(createVerifierPass());
60 // Keep track of how many passes we made for -stopAfterNPasses
63 delete P; // We don't want this pass to run, just delete it now
68 void AddConfiguredTransformationPasses(PassManager &PM) {
69 if (Verify) PM.add(createVerifierPass());
71 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
72 addPass(PM, createGlobalDCEPass()); // Kill unused uinit g-vars
73 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
74 addPass(PM, createConstantMergePass()); // Merge dup global constants
75 addPass(PM, createDeadInstEliminationPass()); // Remove Dead code/vars
76 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
77 addPass(PM, createIndVarSimplifyPass()); // Simplify indvars
79 // Level raise is eternally buggy/in need of enhancements. Allow
80 // transformation to stop right before it runs.
81 if (StopAtLevelRaise) return;
83 addPass(PM, createRaisePointerReferencesPass(TD));// Eliminate casts
84 addPass(PM, createPromoteMemoryToRegister()); // Promote alloca's to regs
85 // Disabling until this is fixed -- Vikram, 7/7/02.
86 // addPass(PM, createReassociatePass()); // Reassociate expressions
87 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
88 addPass(PM, createDeadInstEliminationPass()); // Kill InstCombine remnants
89 addPass(PM, createLICMPass()); // Hoist loop invariants
90 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
91 addPass(PM, createGCSEPass()); // Remove common subexprs
92 addPass(PM, createSCCPPass()); // Constant prop with SCCP
94 // Run instcombine after redundancy elimination to exploit opportunities
96 addPass(PM, createInstructionCombiningPass());
97 addPass(PM, createAggressiveDCEPass()); // SSA based 'Agressive DCE'
98 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
102 int main(int argc, char **argv) {
103 cl::ParseCommandLineOptions(argc, argv, " llvm .s -> .o assembler for GCC\n");
105 std::auto_ptr<Module> M;
107 // Parse the file now...
108 M.reset(ParseAssemblyFile(InputFilename));
109 } catch (const ParseException &E) {
110 cerr << argv[0] << ": " << E.getMessage() << "\n";
115 cerr << argv[0] << ": assembly didn't read correctly.\n";
119 if (OutputFilename == "") { // Didn't specify an output filename?
120 std::string IFN = InputFilename;
121 int Len = IFN.length();
122 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
123 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
125 OutputFilename = IFN; // Append a .o to it
127 OutputFilename += ".o";
130 std::ofstream Out(OutputFilename.c_str(), std::ios::out);
132 cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
136 // Make sure that the Out file gets unlink'd from the disk if we get a SIGINT
137 RemoveFileOnSignal(OutputFilename);
139 // In addition to just parsing the input from GCC, we also want to spiff it up
140 // a little bit. Do this now.
144 // Add all of the transformation passes to the pass manager to do the cleanup
145 // and optimization of the GCC output.
147 AddConfiguredTransformationPasses(Passes);
149 // Write bytecode to file...
150 Passes.add(new WriteBytecodePass(&Out));
152 // Run our queue of passes all at once now, efficiently.
153 Passes.run(*M.get());