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/Support/Streams.h"
27 #include "llvm/System/Signals.h"
35 InputFilename(cl::Positional,cl::desc("<input llvm assembly>"),cl::init("-"));
38 OutputFilename("o", cl::desc("Override output filename"),
39 cl::value_desc("filename"));
42 Verify("verify", cl::desc("Verify each pass result"));
45 DisableInline("disable-inlining", cl::desc("Do not run the inliner pass"));
48 DisableOptimizations("disable-opt",
49 cl::desc("Do not run any optimization passes"));
52 StripDebug("strip-debug",
53 cl::desc("Strip debugger symbol info from translation unit"));
56 NoCompress("disable-compression", cl::init(false),
57 cl::desc("Don't compress the generated bytecode"));
59 cl::opt<bool> TF("traditional-format", cl::Hidden,
60 cl::desc("Compatibility option: ignored"));
64 static inline void addPass(PassManager &PM, Pass *P) {
65 // Add the pass to the pass manager...
68 // If we are verifying all of the intermediate steps, add the verifier...
69 if (Verify) PM.add(createVerifierPass());
73 void AddConfiguredTransformationPasses(PassManager &PM) {
74 PM.add(createVerifierPass()); // Verify that input is correct
76 addPass(PM, createLowerSetJmpPass()); // Lower llvm.setjmp/.longjmp
77 addPass(PM, createFunctionResolvingPass()); // Resolve (...) functions
79 // If the -strip-debug command line option was specified, do it.
81 addPass(PM, createStripSymbolsPass(true));
83 if (DisableOptimizations) return;
85 addPass(PM, createRaiseAllocationsPass()); // call %malloc -> malloc inst
86 addPass(PM, createCFGSimplificationPass()); // Clean up disgusting code
87 addPass(PM, createPromoteMemoryToRegisterPass());// Kill useless allocas
88 addPass(PM, createGlobalOptimizerPass()); // Optimize out global vars
89 addPass(PM, createGlobalDCEPass()); // Remove unused fns and globs
90 addPass(PM, createIPConstantPropagationPass());// IP Constant Propagation
91 addPass(PM, createDeadArgEliminationPass()); // Dead argument elimination
92 addPass(PM, createInstructionCombiningPass()); // Clean up after IPCP & DAE
93 addPass(PM, createCFGSimplificationPass()); // Clean up after IPCP & DAE
95 addPass(PM, createPruneEHPass()); // Remove dead EH info
98 addPass(PM, createFunctionInliningPass()); // Inline small functions
99 addPass(PM, createSimplifyLibCallsPass()); // Library Call Optimizations
100 addPass(PM, createArgumentPromotionPass()); // Scalarize uninlined fn args
102 addPass(PM, createRaisePointerReferencesPass());// Recover type information
103 addPass(PM, createTailDuplicationPass()); // Simplify cfg by copying code
104 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
105 addPass(PM, createScalarReplAggregatesPass()); // Break up aggregate allocas
106 addPass(PM, createInstructionCombiningPass()); // Combine silly seq's
107 addPass(PM, createCondPropagationPass()); // Propagate conditionals
109 addPass(PM, createTailCallEliminationPass()); // Eliminate tail calls
110 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
111 addPass(PM, createReassociatePass()); // Reassociate expressions
112 addPass(PM, createLICMPass()); // Hoist loop invariants
113 addPass(PM, createLoopUnswitchPass()); // Unswitch loops.
114 addPass(PM, createInstructionCombiningPass()); // Clean up after LICM/reassoc
115 addPass(PM, createIndVarSimplifyPass()); // Canonicalize indvars
116 addPass(PM, createLoopUnrollPass()); // Unroll small loops
117 addPass(PM, createInstructionCombiningPass()); // Clean up after the unroller
118 addPass(PM, createLoadValueNumberingPass()); // GVN for load instructions
119 addPass(PM, createGCSEPass()); // Remove common subexprs
120 addPass(PM, createSCCPPass()); // Constant prop with SCCP
122 // Run instcombine after redundancy elimination to exploit opportunities
123 // opened up by them.
124 addPass(PM, createInstructionCombiningPass());
125 addPass(PM, createCondPropagationPass()); // Propagate conditionals
127 addPass(PM, createDeadStoreEliminationPass()); // Delete dead stores
128 addPass(PM, createAggressiveDCEPass()); // SSA based 'Aggressive DCE'
129 addPass(PM, createCFGSimplificationPass()); // Merge & remove BBs
130 addPass(PM, createDeadTypeEliminationPass()); // Eliminate dead types
131 addPass(PM, createConstantMergePass()); // Merge dup global constants
135 int main(int argc, char **argv) {
137 cl::ParseCommandLineOptions(argc, argv,
138 " llvm .s -> .o assembler for GCC\n");
139 sys::PrintStackTraceOnErrorSignal();
142 std::auto_ptr<Module> M(ParseAssemblyFile(InputFilename,&Err));
144 llvm_cerr << argv[0] << ": " << Err.getMessage() << "\n";
148 std::ostream *Out = 0;
149 if (OutputFilename == "") { // Didn't specify an output filename?
150 if (InputFilename == "-") {
151 OutputFilename = "-";
153 std::string IFN = InputFilename;
154 int Len = IFN.length();
155 if (IFN[Len-2] == '.' && IFN[Len-1] == 's') { // Source ends in .s?
156 OutputFilename = std::string(IFN.begin(), IFN.end()-2);
158 OutputFilename = IFN; // Append a .o to it
160 OutputFilename += ".o";
164 if (OutputFilename == "-")
165 // FIXME: cout is not binary!
168 std::ios::openmode io_mode = std::ios::out | std::ios::trunc |
170 Out = new std::ofstream(OutputFilename.c_str(), io_mode);
172 // Make sure that the Out file gets unlinked from the disk if we get a
174 sys::RemoveFileOnSignal(sys::Path(OutputFilename));
179 llvm_cerr << argv[0] << ": error opening " << OutputFilename << "!\n";
183 // In addition to just parsing the input from GCC, we also want to spiff
184 // it up a little bit. Do this now.
187 // Add an appropriate TargetData instance for this module...
188 Passes.add(new TargetData(M.get()));
190 // Add all of the transformation passes to the pass manager to do the
191 // cleanup and optimization of the GCC output.
192 AddConfiguredTransformationPasses(Passes);
194 // Make sure everything is still good.
195 Passes.add(createVerifierPass());
197 // Write bytecode to file...
198 llvm_ostream L(*Out);
199 Passes.add(new WriteBytecodePass(&L,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 llvm_cerr << argv[0] << ": " << msg << "\n";
209 llvm_cerr << argv[0] << ": Unexpected unknown exception occurred.\n";