llvm-6502/tools/llvm-dis/llvm-dis.cpp
Rafael Espindola 68016e0a6e Use the DiagnosticHandler to print diagnostics when reading bitcode.
The bitcode reading interface used std::error_code to report an error to the
callers and it is the callers job to print diagnostics.

This is not ideal for error handling or diagnostic reporting:

* For error handling, all that the callers care about is 3 possibilities:
  * It worked
  * The bitcode file is corrupted/invalid.
  * The file is not bitcode at all.

* For diagnostic, it is user friendly to include far more information
  about the invalid case so the user can find out what is wrong with the
  bitcode file. This comes up, for example, when a developer introduces a
  bug while extending the format.

The compromise we had was to have a lot of error codes.

With this patch we use the DiagnosticHandler to communicate with the
human and std::error_code to communicate with the caller.

This allows us to have far fewer error codes and adds the infrastructure to
print better diagnostics. This is so because the diagnostics are printed when
he issue is found. The code that detected the problem in alive in the stack and
can pass down as much context as needed. As an example the patch updates
test/Bitcode/invalid.ll.

Using a DiagnosticHandler also moves the fatal/non-fatal error decision to the
caller. A simple one like llvm-dis can just use fatal errors. The gold plugin
needs a bit more complex treatment because of being passed non-bitcode files. An
hypothetical interactive tool would make all bitcode errors non-fatal.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@225562 91177308-0d34-0410-b5e6-96231b3b80d8
2015-01-10 00:07:30 +00:00

196 lines
5.9 KiB
C++

//===-- llvm-dis.cpp - The low-level LLVM disassembler --------------------===//
//
// 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-dis [options] - Read LLVM bitcode from stdin, write asm to stdout
// llvm-dis [options] x.bc - Read LLVM bitcode from the x.bc file, write asm
// to the x.ll file.
// Options:
// --help - Output information about command line switches
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/LLVMContext.h"
#include "llvm/Bitcode/ReaderWriter.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/DiagnosticPrinter.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/DataStream.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/Signals.h"
#include "llvm/Support/ToolOutputFile.h"
#include <system_error>
using namespace llvm;
static cl::opt<std::string>
InputFilename(cl::Positional, cl::desc("<input bitcode>"), 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>
DontPrint("disable-output", cl::desc("Don't output the .ll file"), cl::Hidden);
static cl::opt<bool>
ShowAnnotations("show-annotations",
cl::desc("Add informational comments to the .ll file"));
namespace {
static void printDebugLoc(const DebugLoc &DL, formatted_raw_ostream &OS) {
OS << DL.getLine() << ":" << DL.getCol();
if (MDNode *N = DL.getInlinedAt(getGlobalContext())) {
DebugLoc IDL = DebugLoc::getFromDILocation(N);
if (!IDL.isUnknown()) {
OS << "@";
printDebugLoc(IDL,OS);
}
}
}
class CommentWriter : public AssemblyAnnotationWriter {
public:
void emitFunctionAnnot(const Function *F,
formatted_raw_ostream &OS) override {
OS << "; [#uses=" << F->getNumUses() << ']'; // Output # uses
OS << '\n';
}
void printInfoComment(const Value &V, formatted_raw_ostream &OS) override {
bool Padded = false;
if (!V.getType()->isVoidTy()) {
OS.PadToColumn(50);
Padded = true;
OS << "; [#uses=" << V.getNumUses() << " type=" << *V.getType() << "]"; // Output # uses and type
}
if (const Instruction *I = dyn_cast<Instruction>(&V)) {
const DebugLoc &DL = I->getDebugLoc();
if (!DL.isUnknown()) {
if (!Padded) {
OS.PadToColumn(50);
Padded = true;
OS << ";";
}
OS << " [debug line = ";
printDebugLoc(DL,OS);
OS << "]";
}
if (const DbgDeclareInst *DDI = dyn_cast<DbgDeclareInst>(I)) {
DIVariable Var(DDI->getVariable());
if (!Padded) {
OS.PadToColumn(50);
OS << ";";
}
OS << " [debug variable = " << Var.getName() << "]";
}
else if (const DbgValueInst *DVI = dyn_cast<DbgValueInst>(I)) {
DIVariable Var(DVI->getVariable());
if (!Padded) {
OS.PadToColumn(50);
OS << ";";
}
OS << " [debug variable = " << Var.getName() << "]";
}
}
}
};
} // end anon namespace
static void diagnosticHandler(const DiagnosticInfo &DI, void *Context) {
assert(DI.getSeverity() == DS_Error && "Only expecting errors");
raw_ostream &OS = errs();
OS << (char *)Context << ": ";
DiagnosticPrinterRawOStream DP(OS);
DI.print(DP);
OS << '\n';
exit(1);
}
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.
Context.setDiagnosticHandler(diagnosticHandler, argv[0]);
cl::ParseCommandLineOptions(argc, argv, "llvm .bc -> .ll disassembler\n");
std::string ErrorMessage;
std::unique_ptr<Module> M;
// Use the bitcode streaming interface
DataStreamer *Streamer = getDataFileStreamer(InputFilename, &ErrorMessage);
if (Streamer) {
std::string DisplayFilename;
if (InputFilename == "-")
DisplayFilename = "<stdin>";
else
DisplayFilename = InputFilename;
ErrorOr<std::unique_ptr<Module>> MOrErr =
getStreamedBitcodeModule(DisplayFilename, Streamer, Context);
M = std::move(*MOrErr);
M->materializeAllPermanently();
}
// Just use stdout. We won't actually print anything on it.
if (DontPrint)
OutputFilename = "-";
if (OutputFilename.empty()) { // Unspecified output, infer it.
if (InputFilename == "-") {
OutputFilename = "-";
} else {
const std::string &IFN = InputFilename;
int Len = IFN.length();
// If the source ends in .bc, strip it off.
if (IFN[Len-3] == '.' && IFN[Len-2] == 'b' && IFN[Len-1] == 'c')
OutputFilename = std::string(IFN.begin(), IFN.end()-3)+".ll";
else
OutputFilename = IFN+".ll";
}
}
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';
return 1;
}
std::unique_ptr<AssemblyAnnotationWriter> Annotator;
if (ShowAnnotations)
Annotator.reset(new CommentWriter());
// All that llvm-dis does is write the assembly to a file.
if (!DontPrint)
M->print(Out->os(), Annotator.get());
// Declare success.
Out->keep();
return 0;
}