1 //===-- gccas.cpp - The "optimizing assembler" used by the GCC frontend ---===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by the LLVM research group and is distributed under
6 // the University of Illinois Open Source License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This utility is designed to be used by the GCC frontend for creating bytecode
11 // files from its intermediate LLVM assembly. The requirements for this utility
12 // are thus slightly different than that of the standard `as' util.
14 //===----------------------------------------------------------------------===//
16 #include "llvm/Module.h"
17 #include "llvm/PassManager.h"
18 #include "llvm/Analysis/LoadValueNumbering.h"
19 #include "llvm/Analysis/Verifier.h"
20 #include "llvm/Assembly/Parser.h"
21 #include "llvm/Bytecode/WriteBytecodePass.h"
22 #include "llvm/Target/TargetData.h"
23 #include "llvm/Transforms/IPO.h"
24 #include "llvm/Transforms/Scalar.h"
25 #include "Support/CommandLine.h"
26 #include "Support/Signals.h"
32 InputFilename(cl::Positional,cl::desc("<input llvm assembly>"),cl::init("-"));
35 OutputFilename("o", cl::desc("Override output filename"),
36 cl::value_desc("filename"));
39 Verify("verify", cl::desc("Verify each pass result"));
42 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
46 static inline void addPass(PassManager &PM, Pass *P) {
47 // Add the pass to the pass manager...
50 // If we are verifying all of the intermediate steps, add the verifier...
51 if (Verify) PM.add(createVerifierPass());
55 void AddConfiguredTransformationPasses(PassManager &PM) {
56 PM.add(createVerifierPass()); // Verify that input is correct
57 addPass(PM, createLowerSetJmpPass()); // Lower llvm.setjmp/.longjmp
58 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
59 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
60 addPass(PM, createGlobalDCEPass()); // Remove unused globals
61 addPass(PM, createPruneEHPass()); // Remove dead EH info
64 addPass(PM, createFunctionInliningPass()); // Inline small functions
66 addPass(PM, createInstructionCombiningPass()); // Cleanup code for raise
67 addPass(PM, createRaisePointerReferencesPass());// Recover type information
68 addPass(PM, createTailDuplicationPass()); // Simplify cfg by copying code
69 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
70 addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
71 addPass(PM, createTailCallEliminationPass()); // Eliminate tail calls
72 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
74 addPass(PM, createReassociatePass()); // Reassociate expressions
75 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
76 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
77 addPass(PM, createLICMPass()); // Hoist loop invariants
78 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
79 addPass(PM, createGCSEPass()); // Remove common subexprs
80 addPass(PM, createSCCPPass()); // Constant prop with SCCP
82 // Run instcombine after redundancy elimination to exploit opportunities
84 addPass(PM, createInstructionCombiningPass());
85 addPass(PM, createIndVarSimplifyPass()); // Canonicalize indvars
86 addPass(PM, createAggressiveDCEPass()); // SSA based 'Aggressive DCE'
87 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
88 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
89 addPass(PM, createConstantMergePass()); // Merge dup global constants
93 int main(int argc, char **argv) {
94 cl::ParseCommandLineOptions(argc, argv, " llvm .s -> .o assembler for GCC\n");
96 std::auto_ptr<Module> M;
98 // Parse the file now...
99 M.reset(ParseAssemblyFile(InputFilename));
100 } catch (const ParseException &E) {
101 std::cerr << argv[0] << ": " << E.getMessage() << "\n";
106 std::cerr << argv[0] << ": assembly didn't read correctly.\n";
110 std::ostream *Out = 0;
111 if (OutputFilename == "") { // Didn't specify an output filename?
112 if (InputFilename == "-") {
113 OutputFilename = "-";
115 std::string IFN = InputFilename;
116 int Len = IFN.length();
117 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
118 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
120 OutputFilename = IFN; // Append a .o to it
122 OutputFilename += ".o";
126 if (OutputFilename == "-")
129 Out = new std::ofstream(OutputFilename.c_str(), std::ios::out);
131 // Make sure that the Out file gets unlinked from the disk if we get a
133 RemoveFileOnSignal(OutputFilename);
138 std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
142 // In addition to just parsing the input from GCC, we also want to spiff it up
143 // a little bit. Do this now.
147 // Add an appropriate TargetData instance for this module...
148 Passes.add(new TargetData("gccas", M.get()));
150 // Add all of the transformation passes to the pass manager to do the cleanup
151 // and optimization of the GCC output.
153 AddConfiguredTransformationPasses(Passes);
155 // Write bytecode to file...
156 Passes.add(new WriteBytecodePass(Out));
158 // Run our queue of passes all at once now, efficiently.
159 Passes.run(*M.get());
161 if (Out != &std::cout) delete Out;