1 //===-- gccas.cpp - The "optimizing assembler" used by the GCC frontend ---===//
3 // This utility is designed to be used by the GCC frontend for creating bytecode
4 // files from its intermediate LLVM assembly. The requirements for this utility
5 // are thus slightly different than that of the standard `as' util.
7 //===----------------------------------------------------------------------===//
9 #include "llvm/Module.h"
10 #include "llvm/PassManager.h"
11 #include "llvm/Analysis/LoadValueNumbering.h"
12 #include "llvm/Analysis/Verifier.h"
13 #include "llvm/Assembly/Parser.h"
14 #include "llvm/Bytecode/WriteBytecodePass.h"
15 #include "llvm/Target/TargetData.h"
16 #include "llvm/Transforms/IPO.h"
17 #include "llvm/Transforms/Scalar.h"
18 #include "Support/CommandLine.h"
19 #include "Support/Signals.h"
25 InputFilename(cl::Positional,cl::desc("<input llvm assembly>"),cl::init("-"));
28 OutputFilename("o", cl::desc("Override output filename"),
29 cl::value_desc("filename"));
32 Verify("verify", cl::desc("Verify each pass result"));
35 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
39 static inline void addPass(PassManager &PM, Pass *P) {
40 // Add the pass to the pass manager...
43 // If we are verifying all of the intermediate steps, add the verifier...
44 if (Verify) PM.add(createVerifierPass());
48 void AddConfiguredTransformationPasses(PassManager &PM) {
49 PM.add(createVerifierPass()); // Verify that input is correct
50 addPass(PM, createLowerSetJmpPass()); // Lower llvm.setjmp/.longjmp
51 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
52 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
53 addPass(PM, createGlobalDCEPass()); // Remove unused globals
54 addPass(PM, createPruneEHPass()); // Remove dead EH info
57 addPass(PM, createFunctionInliningPass()); // Inline small functions
59 addPass(PM, createInstructionCombiningPass()); // Cleanup code for raise
60 // FIXME: levelraise pass disabled until it can be rewritten at a later date.
61 //addPass(PM, createRaisePointerReferencesPass());// Recover type information
62 addPass(PM, createTailDuplicationPass()); // Simplify cfg by copying code
63 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
64 addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
65 addPass(PM, createTailCallEliminationPass()); // Eliminate tail calls
66 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
68 addPass(PM, createReassociatePass()); // Reassociate expressions
69 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
70 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
71 addPass(PM, createLICMPass()); // Hoist loop invariants
72 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
73 addPass(PM, createGCSEPass()); // Remove common subexprs
74 addPass(PM, createSCCPPass()); // Constant prop with SCCP
76 // Run instcombine after redundancy elimination to exploit opportunities
78 addPass(PM, createInstructionCombiningPass());
79 addPass(PM, createIndVarSimplifyPass()); // Canonicalize indvars
80 addPass(PM, createAggressiveDCEPass()); // SSA based 'Aggressive DCE'
81 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
82 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
83 addPass(PM, createConstantMergePass()); // Merge dup global constants
87 int main(int argc, char **argv) {
88 cl::ParseCommandLineOptions(argc, argv, " llvm .s -> .o assembler for GCC\n");
90 std::auto_ptr<Module> M;
92 // Parse the file now...
93 M.reset(ParseAssemblyFile(InputFilename));
94 } catch (const ParseException &E) {
95 std::cerr << argv[0] << ": " << E.getMessage() << "\n";
100 std::cerr << argv[0] << ": assembly didn't read correctly.\n";
104 std::ostream *Out = 0;
105 if (OutputFilename == "") { // Didn't specify an output filename?
106 if (InputFilename == "-") {
107 OutputFilename = "-";
109 std::string IFN = InputFilename;
110 int Len = IFN.length();
111 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
112 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
114 OutputFilename = IFN; // Append a .o to it
116 OutputFilename += ".o";
120 if (OutputFilename == "-")
123 Out = new std::ofstream(OutputFilename.c_str(), std::ios::out);
125 // Make sure that the Out file gets unlinked from the disk if we get a
127 RemoveFileOnSignal(OutputFilename);
132 std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
136 // In addition to just parsing the input from GCC, we also want to spiff it up
137 // a little bit. Do this now.
141 // Add an appropriate TargetData instance for this module...
142 Passes.add(new TargetData("gccas", M.get()));
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());
155 if (Out != &std::cout) delete Out;