X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=tools%2Fllc%2Fllc.cpp;h=bffa39fd9e5c5ba53b157e09c82425f61f5d2b85;hb=d26a2e75e58f56a289b911c0bf582be4f8f655f1;hp=04e5bca38550f4db540e89ae4a3cd34e60eea646;hpb=3b9a911efcf280950f878a050728450423875639;p=oota-llvm.git

diff --git a/tools/llc/llc.cpp b/tools/llc/llc.cpp
index 04e5bca3855..bffa39fd9e5 100644
--- a/tools/llc/llc.cpp
+++ b/tools/llc/llc.cpp
@@ -13,30 +13,39 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "llvm/LLVMContext.h"
-#include "llvm/DataLayout.h"
-#include "llvm/Module.h"
-#include "llvm/PassManager.h"
-#include "llvm/Pass.h"
+
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/Triple.h"
-#include "llvm/Assembly/PrintModulePass.h"
-#include "llvm/Support/IRReader.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+#include "llvm/CodeGen/CommandFlags.h"
 #include "llvm/CodeGen/LinkAllAsmWriterComponents.h"
 #include "llvm/CodeGen/LinkAllCodegenComponents.h"
+#include "llvm/CodeGen/MIRParser/MIRParser.h"
+#include "llvm/IR/DataLayout.h"
+#include "llvm/IR/IRPrintingPasses.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/IR/LegacyPassManager.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/Verifier.h"
+#include "llvm/IRReader/IRReader.h"
 #include "llvm/MC/SubtargetFeature.h"
+#include "llvm/Pass.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Debug.h"
+#include "llvm/Support/FileSystem.h"
 #include "llvm/Support/FormattedStream.h"
+#include "llvm/Support/Host.h"
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/PluginLoader.h"
 #include "llvm/Support/PrettyStackTrace.h"
-#include "llvm/Support/ToolOutputFile.h"
-#include "llvm/Support/Host.h"
 #include "llvm/Support/Signals.h"
+#include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/TargetRegistry.h"
 #include "llvm/Support/TargetSelect.h"
-#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Support/ToolOutputFile.h"
 #include "llvm/Target/TargetMachine.h"
+#include "llvm/Target/TargetSubtargetInfo.h"
+#include "llvm/Transforms/Utils/Cloning.h"
 #include <memory>
 using namespace llvm;
 
@@ -50,6 +59,15 @@ InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
 static cl::opt<std::string>
 OutputFilename("o", cl::desc("Output filename"), cl::value_desc("filename"));
 
+static cl::opt<unsigned>
+TimeCompilations("time-compilations", cl::Hidden, cl::init(1u),
+                 cl::value_desc("N"),
+                 cl::desc("Repeat compilation N times for timing"));
+
+static cl::opt<bool>
+NoIntegratedAssembler("no-integrated-as", cl::Hidden,
+                      cl::desc("Disable integrated assembler"));
+
 // Determine optimization level.
 static cl::opt<char>
 OptLevel("O",
@@ -62,243 +80,47 @@ OptLevel("O",
 static cl::opt<std::string>
 TargetTriple("mtriple", cl::desc("Override target triple for module"));
 
-static cl::opt<std::string>
-MArch("march", cl::desc("Architecture to generate code for (see --version)"));
-
-static cl::opt<std::string>
-MCPU("mcpu",
-  cl::desc("Target a specific cpu type (-mcpu=help for details)"),
-  cl::value_desc("cpu-name"),
-  cl::init(""));
-
-static cl::list<std::string>
-MAttrs("mattr",
-  cl::CommaSeparated,
-  cl::desc("Target specific attributes (-mattr=help for details)"),
-  cl::value_desc("a1,+a2,-a3,..."));
-
-static cl::opt<Reloc::Model>
-RelocModel("relocation-model",
-             cl::desc("Choose relocation model"),
-             cl::init(Reloc::Default),
-             cl::values(
-            clEnumValN(Reloc::Default, "default",
-                       "Target default relocation model"),
-            clEnumValN(Reloc::Static, "static",
-                       "Non-relocatable code"),
-            clEnumValN(Reloc::PIC_, "pic",
-                       "Fully relocatable, position independent code"),
-            clEnumValN(Reloc::DynamicNoPIC, "dynamic-no-pic",
-                       "Relocatable external references, non-relocatable code"),
-            clEnumValEnd));
-
-static cl::opt<llvm::CodeModel::Model>
-CMModel("code-model",
-        cl::desc("Choose code model"),
-        cl::init(CodeModel::Default),
-        cl::values(clEnumValN(CodeModel::Default, "default",
-                              "Target default code model"),
-                   clEnumValN(CodeModel::Small, "small",
-                              "Small code model"),
-                   clEnumValN(CodeModel::Kernel, "kernel",
-                              "Kernel code model"),
-                   clEnumValN(CodeModel::Medium, "medium",
-                              "Medium code model"),
-                   clEnumValN(CodeModel::Large, "large",
-                              "Large code model"),
-                   clEnumValEnd));
-
-static cl::opt<bool>
-RelaxAll("mc-relax-all",
-  cl::desc("When used with filetype=obj, "
-           "relax all fixups in the emitted object file"));
-
-cl::opt<TargetMachine::CodeGenFileType>
-FileType("filetype", cl::init(TargetMachine::CGFT_AssemblyFile),
-  cl::desc("Choose a file type (not all types are supported by all targets):"),
-  cl::values(
-       clEnumValN(TargetMachine::CGFT_AssemblyFile, "asm",
-                  "Emit an assembly ('.s') file"),
-       clEnumValN(TargetMachine::CGFT_ObjectFile, "obj",
-                  "Emit a native object ('.o') file"),
-       clEnumValN(TargetMachine::CGFT_Null, "null",
-                  "Emit nothing, for performance testing"),
-       clEnumValEnd));
-
-cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
-                       cl::desc("Do not verify input module"));
-
-cl::opt<bool> DisableDotLoc("disable-dot-loc", cl::Hidden,
-                            cl::desc("Do not use .loc entries"));
-
-cl::opt<bool> DisableCFI("disable-cfi", cl::Hidden,
-                         cl::desc("Do not use .cfi_* directives"));
-
-cl::opt<bool> EnableDwarfDirectory("enable-dwarf-directory", cl::Hidden,
-    cl::desc("Use .file directives with an explicit directory."));
-
-static cl::opt<bool>
-DisableRedZone("disable-red-zone",
-  cl::desc("Do not emit code that uses the red zone."),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableFPMAD("enable-fp-mad",
-  cl::desc("Enable less precise MAD instructions to be generated"),
-  cl::init(false));
-
-static cl::opt<bool>
-DisableFPElim("disable-fp-elim",
-  cl::desc("Disable frame pointer elimination optimization"),
-  cl::init(false));
-
-static cl::opt<bool>
-DisableFPElimNonLeaf("disable-non-leaf-fp-elim",
-  cl::desc("Disable frame pointer elimination optimization for non-leaf funcs"),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableUnsafeFPMath("enable-unsafe-fp-math",
-  cl::desc("Enable optimizations that may decrease FP precision"),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableNoInfsFPMath("enable-no-infs-fp-math",
-  cl::desc("Enable FP math optimizations that assume no +-Infs"),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableNoNaNsFPMath("enable-no-nans-fp-math",
-  cl::desc("Enable FP math optimizations that assume no NaNs"),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableHonorSignDependentRoundingFPMath("enable-sign-dependent-rounding-fp-math",
-  cl::Hidden,
-  cl::desc("Force codegen to assume rounding mode can change dynamically"),
-  cl::init(false));
-
-static cl::opt<bool>
-GenerateSoftFloatCalls("soft-float",
-  cl::desc("Generate software floating point library calls"),
-  cl::init(false));
-
-static cl::opt<llvm::FloatABI::ABIType>
-FloatABIForCalls("float-abi",
-  cl::desc("Choose float ABI type"),
-  cl::init(FloatABI::Default),
-  cl::values(
-    clEnumValN(FloatABI::Default, "default",
-               "Target default float ABI type"),
-    clEnumValN(FloatABI::Soft, "soft",
-               "Soft float ABI (implied by -soft-float)"),
-    clEnumValN(FloatABI::Hard, "hard",
-               "Hard float ABI (uses FP registers)"),
-    clEnumValEnd));
-
-static cl::opt<llvm::FPOpFusion::FPOpFusionMode>
-FuseFPOps("fp-contract",
-  cl::desc("Enable aggresive formation of fused FP ops"),
-  cl::init(FPOpFusion::Standard),
-  cl::values(
-    clEnumValN(FPOpFusion::Fast, "fast",
-               "Fuse FP ops whenever profitable"),
-    clEnumValN(FPOpFusion::Standard, "on",
-               "Only fuse 'blessed' FP ops."),
-    clEnumValN(FPOpFusion::Strict, "off",
-               "Only fuse FP ops when the result won't be effected."),
-    clEnumValEnd));
-
-static cl::opt<bool>
-DontPlaceZerosInBSS("nozero-initialized-in-bss",
-  cl::desc("Don't place zero-initialized symbols into bss section"),
-  cl::init(false));
-
-static cl::opt<bool>
-DisableSimplifyLibCalls("disable-simplify-libcalls",
-  cl::desc("Disable simplify-libcalls"),
-  cl::init(false));
-
-static cl::opt<bool>
-EnableGuaranteedTailCallOpt("tailcallopt",
-  cl::desc("Turn fastcc calls into tail calls by (potentially) changing ABI."),
-  cl::init(false));
-
-static cl::opt<bool>
-DisableTailCalls("disable-tail-calls",
-  cl::desc("Never emit tail calls"),
-  cl::init(false));
+static cl::opt<bool> NoVerify("disable-verify", cl::Hidden,
+                              cl::desc("Do not verify input module"));
 
-static cl::opt<unsigned>
-OverrideStackAlignment("stack-alignment",
-  cl::desc("Override default stack alignment"),
-  cl::init(0));
+static cl::opt<bool> DisableSimplifyLibCalls("disable-simplify-libcalls",
+                                             cl::desc("Disable simplify-libcalls"));
 
-static cl::opt<bool>
-EnableRealignStack("realign-stack",
-  cl::desc("Realign stack if needed"),
-  cl::init(true));
+static cl::opt<bool> ShowMCEncoding("show-mc-encoding", cl::Hidden,
+                                    cl::desc("Show encoding in .s output"));
 
-static cl::opt<std::string>
-TrapFuncName("trap-func", cl::Hidden,
-  cl::desc("Emit a call to trap function rather than a trap instruction"),
-  cl::init(""));
+static cl::opt<bool> EnableDwarfDirectory(
+    "enable-dwarf-directory", cl::Hidden,
+    cl::desc("Use .file directives with an explicit directory."));
 
-static cl::opt<bool>
-EnablePIE("enable-pie",
-  cl::desc("Assume the creation of a position independent executable."),
-  cl::init(false));
+static cl::opt<bool> AsmVerbose("asm-verbose",
+                                cl::desc("Add comments to directives."),
+                                cl::init(true));
 
 static cl::opt<bool>
-SegmentedStacks("segmented-stacks",
-  cl::desc("Use segmented stacks if possible."),
-  cl::init(false));
+    CompileTwice("compile-twice", cl::Hidden,
+                 cl::desc("Run everything twice, re-using the same pass "
+                          "manager and verify the result is the same."),
+                 cl::init(false));
 
-static cl::opt<bool>
-UseInitArray("use-init-array",
-  cl::desc("Use .init_array instead of .ctors."),
-  cl::init(false));
-
-static cl::opt<std::string> StopAfter("stop-after",
-  cl::desc("Stop compilation after a specific pass"),
-  cl::value_desc("pass-name"),
-  cl::init(""));
-static cl::opt<std::string> StartAfter("start-after",
-  cl::desc("Resume compilation after a specific pass"),
-  cl::value_desc("pass-name"),
-  cl::init(""));
+static int compileModule(char **, LLVMContext &);
 
-static cl::opt<unsigned>
-SSPBufferSize("stack-protector-buffer-size", cl::init(8),
-              cl::desc("Lower bound for a buffer to be considered for "
-                       "stack protection"));
-
-// GetFileNameRoot - Helper function to get the basename of a filename.
-static inline std::string
-GetFileNameRoot(const std::string &InputFilename) {
-  std::string IFN = InputFilename;
-  std::string outputFilename;
-  int Len = IFN.length();
-  if ((Len > 2) &&
-      IFN[Len-3] == '.' &&
-      ((IFN[Len-2] == 'b' && IFN[Len-1] == 'c') ||
-       (IFN[Len-2] == 'l' && IFN[Len-1] == 'l'))) {
-    outputFilename = std::string(IFN.begin(), IFN.end()-3); // s/.bc/.s/
-  } else {
-    outputFilename = IFN;
-  }
-  return outputFilename;
-}
-
-static tool_output_file *GetOutputStream(const char *TargetName,
-                                         Triple::OSType OS,
-                                         const char *ProgName) {
+static std::unique_ptr<tool_output_file>
+GetOutputStream(const char *TargetName, Triple::OSType OS,
+                const char *ProgName) {
   // If we don't yet have an output filename, make one.
   if (OutputFilename.empty()) {
     if (InputFilename == "-")
       OutputFilename = "-";
     else {
-      OutputFilename = GetFileNameRoot(InputFilename);
+      // If InputFilename ends in .bc or .ll, remove it.
+      StringRef IFN = InputFilename;
+      if (IFN.endswith(".bc") || IFN.endswith(".ll"))
+        OutputFilename = IFN.drop_back(3);
+      else if (IFN.endswith(".mir"))
+        OutputFilename = IFN.drop_back(4);
+      else
+        OutputFilename = IFN;
 
       switch (FileType) {
       case TargetMachine::CGFT_AssemblyFile:
@@ -337,15 +159,15 @@ static tool_output_file *GetOutputStream(const char *TargetName,
   }
 
   // Open the file.
-  std::string error;
-  unsigned OpenFlags = 0;
-  if (Binary) OpenFlags |= raw_fd_ostream::F_Binary;
-  tool_output_file *FDOut = new tool_output_file(OutputFilename.c_str(), error,
-                                                 OpenFlags);
-  if (!error.empty()) {
-    errs() << error << '\n';
-    delete FDOut;
-    return 0;
+  std::error_code EC;
+  sys::fs::OpenFlags OpenFlags = sys::fs::F_None;
+  if (!Binary)
+    OpenFlags |= sys::fs::F_Text;
+  auto FDOut = llvm::make_unique<tool_output_file>(OutputFilename, EC,
+                                                   OpenFlags);
+  if (EC) {
+    errs() << EC.message() << '\n';
+    return nullptr;
   }
 
   return FDOut;
@@ -383,10 +205,19 @@ int main(int argc, char **argv) {
 
   cl::ParseCommandLineOptions(argc, argv, "llvm system compiler\n");
 
+  // Compile the module TimeCompilations times to give better compile time
+  // metrics.
+  for (unsigned I = TimeCompilations; I; --I)
+    if (int RetVal = compileModule(argv, Context))
+      return RetVal;
+  return 0;
+}
+
+static int compileModule(char **argv, LLVMContext &Context) {
   // Load the module to be compiled...
   SMDiagnostic Err;
-  std::auto_ptr<Module> M;
-  Module *mod = 0;
+  std::unique_ptr<Module> M;
+  std::unique_ptr<MIRParser> MIR;
   Triple TheTriple;
 
   bool SkipModule = MCPU == "help" ||
@@ -394,17 +225,31 @@ int main(int argc, char **argv) {
 
   // If user just wants to list available options, skip module loading
   if (!SkipModule) {
-    M.reset(ParseIRFile(InputFilename, Err, Context));
-    mod = M.get();
-    if (mod == 0) {
+    if (StringRef(InputFilename).endswith_lower(".mir")) {
+      MIR = createMIRParserFromFile(InputFilename, Err, Context);
+      if (MIR) {
+        M = MIR->parseLLVMModule();
+        assert(M && "parseLLVMModule should exit on failure");
+      }
+    } else
+      M = parseIRFile(InputFilename, Err, Context);
+    if (!M) {
       Err.print(argv[0], errs());
       return 1;
     }
 
+    // Verify module immediately to catch problems before doInitialization() is
+    // called on any passes.
+    if (!NoVerify && verifyModule(*M, &errs())) {
+      errs() << argv[0] << ": " << InputFilename
+             << ": error: input module is broken!\n";
+      return 1;
+    }
+
     // If we are supposed to override the target triple, do so now.
     if (!TargetTriple.empty())
-      mod->setTargetTriple(Triple::normalize(TargetTriple));
-    TheTriple = Triple(mod->getTargetTriple());
+      M->setTargetTriple(Triple::normalize(TargetTriple));
+    TheTriple = Triple(M->getTargetTriple());
   } else {
     TheTriple = Triple(Triple::normalize(TargetTriple));
   }
@@ -421,14 +266,7 @@ int main(int argc, char **argv) {
     return 1;
   }
 
-  // Package up features to be passed to target/subtarget
-  std::string FeaturesStr;
-  if (MAttrs.size()) {
-    SubtargetFeatures Features;
-    for (unsigned i = 0; i != MAttrs.size(); ++i)
-      Features.AddFeature(MAttrs[i]);
-    FeaturesStr = Features.getString();
-  }
+  std::string CPUStr = getCPUStr(), FeaturesStr = getFeaturesStr();
 
   CodeGenOpt::Level OLvl = CodeGenOpt::Default;
   switch (OptLevel) {
@@ -442,112 +280,108 @@ int main(int argc, char **argv) {
   case '3': OLvl = CodeGenOpt::Aggressive; break;
   }
 
-  TargetOptions Options;
-  Options.LessPreciseFPMADOption = EnableFPMAD;
-  Options.NoFramePointerElim = DisableFPElim;
-  Options.NoFramePointerElimNonLeaf = DisableFPElimNonLeaf;
-  Options.AllowFPOpFusion = FuseFPOps;
-  Options.UnsafeFPMath = EnableUnsafeFPMath;
-  Options.NoInfsFPMath = EnableNoInfsFPMath;
-  Options.NoNaNsFPMath = EnableNoNaNsFPMath;
-  Options.HonorSignDependentRoundingFPMathOption =
-      EnableHonorSignDependentRoundingFPMath;
-  Options.UseSoftFloat = GenerateSoftFloatCalls;
+  TargetOptions Options = InitTargetOptionsFromCodeGenFlags();
+  Options.DisableIntegratedAS = NoIntegratedAssembler;
+  Options.MCOptions.ShowMCEncoding = ShowMCEncoding;
+  Options.MCOptions.MCUseDwarfDirectory = EnableDwarfDirectory;
+  Options.MCOptions.AsmVerbose = AsmVerbose;
+
+  std::unique_ptr<TargetMachine> Target(
+      TheTarget->createTargetMachine(TheTriple.getTriple(), CPUStr, FeaturesStr,
+                                     Options, RelocModel, CMModel, OLvl));
+
+  assert(Target && "Could not allocate target machine!");
+
+  // If we don't have a module then just exit now. We do this down
+  // here since the CPU/Feature help is underneath the target machine
+  // creation.
+  if (SkipModule)
+    return 0;
+
+  assert(M && "Should have exited if we didn't have a module!");
   if (FloatABIForCalls != FloatABI::Default)
     Options.FloatABIType = FloatABIForCalls;
-  Options.NoZerosInBSS = DontPlaceZerosInBSS;
-  Options.GuaranteedTailCallOpt = EnableGuaranteedTailCallOpt;
-  Options.DisableTailCalls = DisableTailCalls;
-  Options.StackAlignmentOverride = OverrideStackAlignment;
-  Options.RealignStack = EnableRealignStack;
-  Options.TrapFuncName = TrapFuncName;
-  Options.PositionIndependentExecutable = EnablePIE;
-  Options.EnableSegmentedStacks = SegmentedStacks;
-  Options.UseInitArray = UseInitArray;
-  Options.SSPBufferSize = SSPBufferSize;
-
-  std::auto_ptr<TargetMachine>
-    target(TheTarget->createTargetMachine(TheTriple.getTriple(),
-                                          MCPU, FeaturesStr, Options,
-                                          RelocModel, CMModel, OLvl));
-  assert(target.get() && "Could not allocate target machine!");
-  assert(mod && "Should have exited after outputting help!");
-  TargetMachine &Target = *target.get();
-
-  if (DisableDotLoc)
-    Target.setMCUseLoc(false);
-
-  if (DisableCFI)
-    Target.setMCUseCFI(false);
-
-  if (EnableDwarfDirectory)
-    Target.setMCUseDwarfDirectory(true);
-
-  if (GenerateSoftFloatCalls)
-    FloatABIForCalls = FloatABI::Soft;
-
-  // Disable .loc support for older OS X versions.
-  if (TheTriple.isMacOSX() &&
-      TheTriple.isMacOSXVersionLT(10, 6))
-    Target.setMCUseLoc(false);
 
   // Figure out where we are going to send the output.
-  OwningPtr<tool_output_file> Out
-    (GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]));
+  std::unique_ptr<tool_output_file> Out =
+      GetOutputStream(TheTarget->getName(), TheTriple.getOS(), argv[0]);
   if (!Out) return 1;
 
   // Build up all of the passes that we want to do to the module.
-  PassManager PM;
+  legacy::PassManager PM;
 
   // Add an appropriate TargetLibraryInfo pass for the module's triple.
-  TargetLibraryInfo *TLI = new TargetLibraryInfo(TheTriple);
+  TargetLibraryInfoImpl TLII(Triple(M->getTargetTriple()));
+
+  // The -disable-simplify-libcalls flag actually disables all builtin optzns.
   if (DisableSimplifyLibCalls)
-    TLI->disableAllFunctions();
-  PM.add(TLI);
+    TLII.disableAllFunctions();
+  PM.add(new TargetLibraryInfoWrapperPass(TLII));
 
   // Add the target data from the target machine, if it exists, or the module.
-  if (const DataLayout *TD = Target.getDataLayout())
-    PM.add(new DataLayout(*TD));
-  else
-    PM.add(new DataLayout(mod));
+  M->setDataLayout(Target->createDataLayout());
 
-  // Override default to generate verbose assembly.
-  Target.setAsmVerbosityDefault(true);
+  // Override function attributes based on CPUStr, FeaturesStr, and command line
+  // flags.
+  setFunctionAttributes(CPUStr, FeaturesStr, *M);
 
-  if (RelaxAll) {
-    if (FileType != TargetMachine::CGFT_ObjectFile)
-      errs() << argv[0]
+  if (RelaxAll.getNumOccurrences() > 0 &&
+      FileType != TargetMachine::CGFT_ObjectFile)
+    errs() << argv[0]
              << ": warning: ignoring -mc-relax-all because filetype != obj";
-    else
-      Target.setMCRelaxAll(true);
-  }
 
   {
-    formatted_raw_ostream FOS(Out->os());
+    raw_pwrite_stream *OS = &Out->os();
+
+    // Manually do the buffering rather than using buffer_ostream,
+    // so we can memcmp the contents in CompileTwice mode
+    SmallVector<char, 0> Buffer;
+    std::unique_ptr<raw_svector_ostream> BOS;
+    if ((FileType != TargetMachine::CGFT_AssemblyFile &&
+         !Out->os().supportsSeeking()) ||
+        CompileTwice) {
+      BOS = make_unique<raw_svector_ostream>(Buffer);
+      OS = BOS.get();
+    }
 
-    AnalysisID StartAfterID = 0;
-    AnalysisID StopAfterID = 0;
+    AnalysisID StartBeforeID = nullptr;
+    AnalysisID StartAfterID = nullptr;
+    AnalysisID StopAfterID = nullptr;
     const PassRegistry *PR = PassRegistry::getPassRegistry();
-    if (!StartAfter.empty()) {
-      const PassInfo *PI = PR->getPassInfo(StartAfter);
-      if (!PI) {
-        errs() << argv[0] << ": start-after pass is not registered.\n";
+    if (!RunPass.empty()) {
+      if (!StartAfter.empty() || !StopAfter.empty()) {
+        errs() << argv[0] << ": start-after and/or stop-after passes are "
+                             "redundant when run-pass is specified.\n";
         return 1;
       }
-      StartAfterID = PI->getTypeInfo();
-    }
-    if (!StopAfter.empty()) {
-      const PassInfo *PI = PR->getPassInfo(StopAfter);
+      const PassInfo *PI = PR->getPassInfo(RunPass);
       if (!PI) {
-        errs() << argv[0] << ": stop-after pass is not registered.\n";
+        errs() << argv[0] << ": run-pass pass is not registered.\n";
         return 1;
       }
-      StopAfterID = PI->getTypeInfo();
+      StopAfterID = StartBeforeID = PI->getTypeInfo();
+    } else {
+      if (!StartAfter.empty()) {
+        const PassInfo *PI = PR->getPassInfo(StartAfter);
+        if (!PI) {
+          errs() << argv[0] << ": start-after pass is not registered.\n";
+          return 1;
+        }
+        StartAfterID = PI->getTypeInfo();
+      }
+      if (!StopAfter.empty()) {
+        const PassInfo *PI = PR->getPassInfo(StopAfter);
+        if (!PI) {
+          errs() << argv[0] << ": stop-after pass is not registered.\n";
+          return 1;
+        }
+        StopAfterID = PI->getTypeInfo();
+      }
     }
 
     // Ask the target to add backend passes as necessary.
-    if (Target.addPassesToEmitFile(PM, FOS, FileType, NoVerify,
-                                   StartAfterID, StopAfterID)) {
+    if (Target->addPassesToEmitFile(PM, *OS, FileType, NoVerify, StartBeforeID,
+                                    StartAfterID, StopAfterID, MIR.get())) {
       errs() << argv[0] << ": target does not support generation of this"
              << " file type!\n";
       return 1;
@@ -556,7 +390,39 @@ int main(int argc, char **argv) {
     // Before executing passes, print the final values of the LLVM options.
     cl::PrintOptionValues();
 
-    PM.run(*mod);
+    // If requested, run the pass manager over the same module again,
+    // to catch any bugs due to persistent state in the passes. Note that
+    // opt has the same functionality, so it may be worth abstracting this out
+    // in the future.
+    SmallVector<char, 0> CompileTwiceBuffer;
+    if (CompileTwice) {
+      std::unique_ptr<Module> M2(llvm::CloneModule(M.get()));
+      PM.run(*M2);
+      CompileTwiceBuffer = Buffer;
+      Buffer.clear();
+    }
+
+    PM.run(*M);
+
+    // Compare the two outputs and make sure they're the same
+    if (CompileTwice) {
+      if (Buffer.size() != CompileTwiceBuffer.size() ||
+          (memcmp(Buffer.data(), CompileTwiceBuffer.data(), Buffer.size()) !=
+           0)) {
+        errs()
+            << "Running the pass manager twice changed the output.\n"
+               "Writing the result of the second run to the specified output\n"
+               "To generate the one-run comparison binary, just run without\n"
+               "the compile-twice option\n";
+        Out->os() << Buffer;
+        Out->keep();
+        return 1;
+      }
+    }
+
+    if (BOS) {
+      Out->os() << Buffer;
+    }
   }
 
   // Declare success.