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 "llvm/Support/CommandLine.h"
26 #include "llvm/System/Signals.h"
34 InputFilename(cl::Positional,cl::desc("<input llvm assembly>"),cl::init("-"));
37 OutputFilename("o", cl::desc("Override output filename"),
38 cl::value_desc("filename"));
41 Verify("verify", cl::desc("Verify each pass result"));
44 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
47 DisableOptimizations("disable-opt",
48 cl::desc("Do not run any optimization passes"));
51 StripDebug("strip-debug",
52 cl::desc("Strip debugger symbol info from translation unit"));
55 NoCompress("disable-compression", cl::init(false),
56 cl::desc("Don't compress the generated bytecode"));
58 cl::opt<bool> TF("traditional-format", cl::Hidden,
59 cl::desc("Compatibility option: ignored"));
63 static inline void addPass(PassManager &PM, Pass *P) {
64 // Add the pass to the pass manager...
67 // If we are verifying all of the intermediate steps, add the verifier...
68 if (Verify) PM.add(createVerifierPass());
72 void AddConfiguredTransformationPasses(PassManager &PM) {
73 PM.add(createVerifierPass()); // Verify that input is correct
75 addPass(PM, createLowerSetJmpPass()); // Lower llvm.setjmp/.longjmp
76 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
78 // If the -strip-debug command line option was specified, do it.
80 addPass(PM, createStripSymbolsPass(true));
82 if (DisableOptimizations) return;
84 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
85 addPass(PM, createCFGSimplificationPass()); // Clean up disgusting code
86 addPass(PM, createPromoteMemoryToRegister()); // Kill useless allocas
87 addPass(PM, createGlobalOptimizerPass()); // Optimize out global vars
88 addPass(PM, createGlobalDCEPass()); // Remove unused fns and globs
89 addPass(PM, createIPConstantPropagationPass());// IP Constant Propagation
90 addPass(PM, createDeadArgEliminationPass()); // Dead argument elimination
91 addPass(PM, createInstructionCombiningPass()); // Clean up after IPCP & DAE
92 addPass(PM, createCFGSimplificationPass()); // Clean up after IPCP & DAE
94 addPass(PM, createPruneEHPass()); // Remove dead EH info
97 addPass(PM, createFunctionInliningPass()); // Inline small functions
98 addPass(PM, createArgumentPromotionPass()); // Scalarize uninlined fn args
100 addPass(PM, createRaisePointerReferencesPass());// Recover type information
101 addPass(PM, createTailDuplicationPass()); // Simplify cfg by copying code
102 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
103 addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
104 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
106 addPass(PM, createReassociatePass()); // Reassociate expressions
107 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
108 addPass(PM, createTailCallEliminationPass()); // Eliminate tail calls
109 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
110 addPass(PM, createLICMPass()); // Hoist loop invariants
111 addPass(PM, createInstructionCombiningPass()); // Clean up after the unroller
112 addPass(PM, createIndVarSimplifyPass()); // Canonicalize indvars
113 addPass(PM, createLoopUnrollPass()); // Unroll small loops
114 addPass(PM, createInstructionCombiningPass()); // Clean up after the unroller
115 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
116 addPass(PM, createGCSEPass()); // Remove common subexprs
117 addPass(PM, createSCCPPass()); // Constant prop with SCCP
119 // Run instcombine after redundancy elimination to exploit opportunities
120 // opened up by them.
121 addPass(PM, createInstructionCombiningPass());
122 addPass(PM, createDeadStoreEliminationPass()); // Delete dead stores
123 addPass(PM, createAggressiveDCEPass()); // SSA based 'Aggressive DCE'
124 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
125 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
126 addPass(PM, createConstantMergePass()); // Merge dup global constants
130 int main(int argc, char **argv) {
132 cl::ParseCommandLineOptions(argc, argv,
133 " llvm .s -> .o assembler for GCC\n");
134 sys::PrintStackTraceOnErrorSignal();
136 std::auto_ptr<Module> M;
138 // Parse the file now...
139 M.reset(ParseAssemblyFile(InputFilename));
140 } catch (const ParseException &E) {
141 std::cerr << argv[0] << ": " << E.getMessage() << "\n";
146 std::cerr << argv[0] << ": assembly didn't read correctly.\n";
150 std::ostream *Out = 0;
151 if (OutputFilename == "") { // Didn't specify an output filename?
152 if (InputFilename == "-") {
153 OutputFilename = "-";
155 std::string IFN = InputFilename;
156 int Len = IFN.length();
157 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
158 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
160 OutputFilename = IFN; // Append a .o to it
162 OutputFilename += ".o";
166 if (OutputFilename == "-")
169 Out = new std::ofstream(OutputFilename.c_str(), std::ios::out);
171 // Make sure that the Out file gets unlinked from the disk if we get a
173 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
178 std::cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
182 // In addition to just parsing the input from GCC, we also want to spiff it up
183 // a little bit. Do this now.
187 // Add an appropriate TargetData instance for this module...
188 Passes.add(new TargetData("gccas", M.get()));
190 // Add all of the transformation passes to the pass manager to do the cleanup
191 // and optimization of the GCC output.
193 AddConfiguredTransformationPasses(Passes);
195 // Make sure everything is still good.
196 Passes.add(createVerifierPass());
198 // Write bytecode to file...
199 Passes.add(new WriteBytecodePass(Out,false,!NoCompress));
201 // Run our queue of passes all at once now, efficiently.
202 Passes.run(*M.get());
204 if (Out != &std::cout) delete Out;
206 } catch (const std::string& msg) {
207 std::cerr << argv[0] << ": " << msg << "\n";
209 std::cerr << argv[0] << ": Unexpected unknown exception occurred.\n";