llvm/tools/llvm-as/llvm-as.cpp
Teresa Johnson b97baa5fe5 Support for function summary index bitcode sections and files.
Summary:
The bitcode format is described in this document:
  https://drive.google.com/file/d/0B036uwnWM6RWdnBLakxmeDdOeXc/view
For more info on ThinLTO see:
  https://sites.google.com/site/llvmthinlto

The first customer is ThinLTO, however the data structures are designed
and named more generally based on prior feedback. There are a few
comments regarding how certain interfaces are used by ThinLTO, and the
options added here to gold currently have ThinLTO-specific names as the
behavior they provoke is currently ThinLTO-specific.

This patch includes support for generating per-module function indexes,
the combined index file via the gold plugin, and several tests
(more are included with the associated clang patch D11908).

Reviewers: dexonsmith, davidxl, joker.eph

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D13107

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249270 91177308-0d34-0410-b5e6-96231b3b80d8
2015-10-04 14:33:43 +00:00

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3.9 KiB
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//===--- llvm-as.cpp - The low-level LLVM assembler -----------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This utility may be invoked in the following manner:
// llvm-as --help - Output information about command line switches
// llvm-as [options] - Read LLVM asm from stdin, write bitcode to stdout
// llvm-as [options] x.ll - Read LLVM asm from the x.ll file, write bitcode
// to the x.bc file.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/LLVMContext.h"
#include "llvm/AsmParser/Parser.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/SourceMgr.h"
#include "llvm/Support/SystemUtils.h"
#include "llvm/Support/ToolOutputFile.h"
#include <memory>
using namespace llvm;
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input .llvm file>"), cl::init("-"));
static cl::opt<std::string>
OutputFilename("o", cl::desc("Override output filename"),
cl::value_desc("filename"));
static cl::opt<bool>
Force("f", cl::desc("Enable binary output on terminals"));
static cl::opt<bool>
DisableOutput("disable-output", cl::desc("Disable output"), cl::init(false));
static cl::opt<bool>
EmitFunctionSummary("function-summary", cl::desc("Emit function summary index"),
cl::init(false));
static cl::opt<bool>
DumpAsm("d", cl::desc("Print assembly as parsed"), cl::Hidden);
static cl::opt<bool>
DisableVerify("disable-verify", cl::Hidden,
cl::desc("Do not run verifier on input LLVM (dangerous!)"));
static cl::opt<bool> PreserveBitcodeUseListOrder(
"preserve-bc-uselistorder",
cl::desc("Preserve use-list order when writing LLVM bitcode."),
cl::init(true), cl::Hidden);
static void WriteOutputFile(const Module *M) {
// Infer the output filename if needed.
if (OutputFilename.empty()) {
if (InputFilename == "-") {
OutputFilename = "-";
} else {
StringRef IFN = InputFilename;
OutputFilename = (IFN.endswith(".ll") ? IFN.drop_back(3) : IFN).str();
OutputFilename += ".bc";
}
}
std::error_code EC;
std::unique_ptr<tool_output_file> Out(
new tool_output_file(OutputFilename, EC, sys::fs::F_None));
if (EC) {
errs() << EC.message() << '\n';
exit(1);
}
if (Force || !CheckBitcodeOutputToConsole(Out->os(), true))
WriteBitcodeToFile(M, Out->os(), PreserveBitcodeUseListOrder,
EmitFunctionSummary);
// Declare success.
Out->keep();
}
int main(int argc, char **argv) {
// Print a stack trace if we signal out.
sys::PrintStackTraceOnErrorSignal();
PrettyStackTraceProgram X(argc, argv);
LLVMContext &Context = getGlobalContext();
llvm_shutdown_obj Y; // Call llvm_shutdown() on exit.
cl::ParseCommandLineOptions(argc, argv, "llvm .ll -> .bc assembler\n");
// Parse the file now...
SMDiagnostic Err;
std::unique_ptr<Module> M = parseAssemblyFile(InputFilename, Err, Context);
if (!M.get()) {
Err.print(argv[0], errs());
return 1;
}
if (!DisableVerify) {
std::string ErrorStr;
raw_string_ostream OS(ErrorStr);
if (verifyModule(*M.get(), &OS)) {
errs() << argv[0]
<< ": assembly parsed, but does not verify as correct!\n";
errs() << OS.str();
return 1;
}
}
if (DumpAsm) errs() << "Here's the assembly:\n" << *M.get();
if (!DisableOutput)
WriteOutputFile(M.get());
return 0;
}