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 Verify("verify", cl::desc("Verify each pass result"));
45 static inline void addPass(PassManager &PM, Pass *P) {
46 static int NumPassesCreated = 0;
48 // If we haven't already created the number of passes that was requested...
49 if (RunNPasses == 0 || RunNPasses > NumPassesCreated) {
50 // Add the pass to the pass manager...
53 // If we are verifying all of the intermediate steps, add the verifier...
54 if (Verify) PM.add(createVerifierPass());
56 // Keep track of how many passes we made for -stopAfterNPasses
59 delete P; // We don't want this pass to run, just delete it now
64 void AddConfiguredTransformationPasses(PassManager &PM) {
65 if (Verify) PM.add(createVerifierPass());
67 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
68 addPass(PM, createGlobalDCEPass()); // Kill unused uinit g-vars
69 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
70 addPass(PM, createConstantMergePass()); // Merge dup global constants
71 addPass(PM, createVerifierPass()); // Verify that input is correct
72 addPass(PM, createDeadInstEliminationPass()); // Remove Dead code/vars
73 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
74 addPass(PM, createIndVarSimplifyPass()); // Simplify indvars
75 addPass(PM, createRaisePointerReferencesPass(TD));// Recover type information
76 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
77 addPass(PM, createPromoteMemoryToRegister()); // Promote alloca's to regs
78 addPass(PM, createReassociatePass()); // Reassociate expressions
79 //addPass(PM, createCorrelatedExpressionEliminationPass());// Kill corr branches
80 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
81 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
82 addPass(PM, createLICMPass()); // Hoist loop invariants
83 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
84 addPass(PM, createGCSEPass()); // Remove common subexprs
85 addPass(PM, createSCCPPass()); // Constant prop with SCCP
87 // Run instcombine after redundancy elimination to exploit opportunities
89 addPass(PM, createInstructionCombiningPass());
90 addPass(PM, createAggressiveDCEPass()); // SSA based 'Agressive DCE'
91 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
95 int main(int argc, char **argv) {
96 cl::ParseCommandLineOptions(argc, argv, " llvm .s -> .o assembler for GCC\n");
98 std::auto_ptr<Module> M;
100 // Parse the file now...
101 M.reset(ParseAssemblyFile(InputFilename));
102 } catch (const ParseException &E) {
103 cerr << argv[0] << ": " << E.getMessage() << "\n";
108 cerr << argv[0] << ": assembly didn't read correctly.\n";
112 if (OutputFilename == "") { // Didn't specify an output filename?
113 std::string IFN = InputFilename;
114 int Len = IFN.length();
115 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
116 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
118 OutputFilename = IFN; // Append a .o to it
120 OutputFilename += ".o";
123 std::ofstream Out(OutputFilename.c_str(), std::ios::out);
125 cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
129 // Make sure that the Out file gets unlink'd from the disk if we get a SIGINT
130 RemoveFileOnSignal(OutputFilename);
132 // In addition to just parsing the input from GCC, we also want to spiff it up
133 // a little bit. Do this now.
137 // Add all of the transformation passes to the pass manager to do the cleanup
138 // and optimization of the GCC output.
140 AddConfiguredTransformationPasses(Passes);
142 // Write bytecode to file...
143 Passes.add(new WriteBytecodePass(&Out));
145 // Run our queue of passes all at once now, efficiently.
146 Passes.run(*M.get());