llvm-6502/lib/Transforms/Instrumentation/DebugIR.cpp

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//===--- DebugIR.cpp - Transform debug metadata to allow debugging IR -----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// A Module transform pass that emits a succinct version of the IR and replaces
// the source file metadata to allow debuggers to step through the IR.
//
// FIXME: instead of replacing debug metadata, this pass should allow for
// additional metadata to be used to point capable debuggers to the IR file
// without destroying the mapping to the original source file.
//
//===----------------------------------------------------------------------===//
#include "llvm/IR/ValueMap.h"
#include "DebugIR.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
#include "llvm/IR/DIBuilder.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DebugInfo.h"
#include "llvm/IR/InstVisitor.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ToolOutputFile.h"
#include "llvm/Transforms/Instrumentation.h"
#include "llvm/Transforms/Utils/Cloning.h"
#include <string>
#define STR_HELPER(x) #x
#define STR(x) STR_HELPER(x)
using namespace llvm;
#define DEBUG_TYPE "debug-ir"
namespace {
/// Builds a map of Value* to line numbers on which the Value appears in a
/// textual representation of the IR by plugging into the AssemblyWriter by
/// masquerading as an AssemblyAnnotationWriter.
class ValueToLineMap : public AssemblyAnnotationWriter {
ValueMap<const Value *, unsigned int> Lines;
typedef ValueMap<const Value *, unsigned int>::const_iterator LineIter;
void addEntry(const Value *V, formatted_raw_ostream &Out) {
Out.flush();
Lines.insert(std::make_pair(V, Out.getLine() + 1));
}
public:
/// Prints Module to a null buffer in order to build the map of Value pointers
/// to line numbers.
ValueToLineMap(const Module *M) {
raw_null_ostream ThrowAway;
M->print(ThrowAway, this);
}
// This function is called after an Instruction, GlobalValue, or GlobalAlias
// is printed.
void printInfoComment(const Value &V, formatted_raw_ostream &Out) override {
addEntry(&V, Out);
}
void emitFunctionAnnot(const Function *F,
formatted_raw_ostream &Out) override {
addEntry(F, Out);
}
/// If V appears on a line in the textual IR representation, sets Line to the
/// line number and returns true, otherwise returns false.
bool getLine(const Value *V, unsigned int &Line) const {
LineIter i = Lines.find(V);
if (i != Lines.end()) {
Line = i->second;
return true;
}
return false;
}
};
/// Removes debug intrisncs like llvm.dbg.declare and llvm.dbg.value.
class DebugIntrinsicsRemover : public InstVisitor<DebugIntrinsicsRemover> {
void remove(Instruction &I) { I.eraseFromParent(); }
public:
static void process(Module &M) {
DebugIntrinsicsRemover Remover;
Remover.visit(&M);
}
void visitDbgDeclareInst(DbgDeclareInst &I) { remove(I); }
void visitDbgValueInst(DbgValueInst &I) { remove(I); }
void visitDbgInfoIntrinsic(DbgInfoIntrinsic &I) { remove(I); }
};
/// Removes debug metadata (!dbg) nodes from all instructions, and optionally
/// metadata named "llvm.dbg.cu" if RemoveNamedInfo is true.
class DebugMetadataRemover : public InstVisitor<DebugMetadataRemover> {
bool RemoveNamedInfo;
public:
static void process(Module &M, bool RemoveNamedInfo = true) {
DebugMetadataRemover Remover(RemoveNamedInfo);
Remover.run(&M);
}
DebugMetadataRemover(bool RemoveNamedInfo)
: RemoveNamedInfo(RemoveNamedInfo) {}
void visitInstruction(Instruction &I) {
if (I.getMetadata(LLVMContext::MD_dbg))
I.setMetadata(LLVMContext::MD_dbg, nullptr);
}
void run(Module *M) {
// Remove debug metadata attached to instructions
visit(M);
if (RemoveNamedInfo) {
// Remove CU named metadata (and all children nodes)
NamedMDNode *Node = M->getNamedMetadata("llvm.dbg.cu");
if (Node)
M->eraseNamedMetadata(Node);
}
}
};
/// Updates debug metadata in a Module:
/// - changes Filename/Directory to values provided on construction
/// - adds/updates line number (DebugLoc) entries associated with each
/// instruction to reflect the instruction's location in an LLVM IR file
class DIUpdater : public InstVisitor<DIUpdater> {
/// Builder of debug information
DIBuilder Builder;
/// Helper for type attributes/sizes/etc
DataLayout Layout;
/// Map of Value* to line numbers
const ValueToLineMap LineTable;
/// Map of Value* (in original Module) to Value* (in optional cloned Module)
const ValueToValueMapTy *VMap;
/// Directory of debug metadata
DebugInfoFinder Finder;
/// Source filename and directory
StringRef Filename;
StringRef Directory;
// CU nodes needed when creating DI subprograms
MDNode *FileNode;
MDNode *LexicalBlockFileNode;
const MDNode *CUNode;
ValueMap<const Function *, MDNode *> SubprogramDescriptors;
DenseMap<const Type *, MDNode *> TypeDescriptors;
public:
DIUpdater(Module &M, StringRef Filename = StringRef(),
StringRef Directory = StringRef(), const Module *DisplayM = nullptr,
const ValueToValueMapTy *VMap = nullptr)
: Builder(M), Layout(&M), LineTable(DisplayM ? DisplayM : &M), VMap(VMap),
Finder(), Filename(Filename), Directory(Directory), FileNode(nullptr),
LexicalBlockFileNode(nullptr), CUNode(nullptr) {
Finder.processModule(M);
visit(&M);
}
~DIUpdater() { Builder.finalize(); }
void visitModule(Module &M) {
if (Finder.compile_unit_count() > 1)
report_fatal_error("DebugIR pass supports only a signle compile unit per "
"Module.");
createCompileUnit(Finder.compile_unit_count() == 1 ?
(MDNode*)*Finder.compile_units().begin() : nullptr);
}
void visitFunction(Function &F) {
if (F.isDeclaration() || findDISubprogram(&F))
return;
StringRef MangledName = F.getName();
DICompositeType Sig = createFunctionSignature(&F);
// find line of function declaration
unsigned Line = 0;
if (!findLine(&F, Line)) {
DEBUG(dbgs() << "WARNING: No line for Function " << F.getName().str()
<< "\n");
return;
}
Instruction *FirstInst = F.begin()->begin();
unsigned ScopeLine = 0;
if (!findLine(FirstInst, ScopeLine)) {
DEBUG(dbgs() << "WARNING: No line for 1st Instruction in Function "
<< F.getName().str() << "\n");
return;
}
bool Local = F.hasInternalLinkage();
bool IsDefinition = !F.isDeclaration();
bool IsOptimized = false;
int FuncFlags = llvm::DIDescriptor::FlagPrototyped;
assert(CUNode && FileNode);
DISubprogram Sub = Builder.createFunction(
DICompileUnit(CUNode), F.getName(), MangledName, DIFile(FileNode), Line,
Sig, Local, IsDefinition, ScopeLine, FuncFlags, IsOptimized, &F);
assert(Sub.isSubprogram());
DEBUG(dbgs() << "create subprogram mdnode " << *Sub << ": "
<< "\n");
SubprogramDescriptors.insert(std::make_pair(&F, Sub));
}
void visitInstruction(Instruction &I) {
DebugLoc Loc(I.getDebugLoc());
/// If a ValueToValueMap is provided, use it to get the real instruction as
/// the line table was generated on a clone of the module on which we are
/// operating.
Value *RealInst = nullptr;
if (VMap)
RealInst = VMap->lookup(&I);
if (!RealInst)
RealInst = &I;
unsigned Col = 0; // FIXME: support columns
unsigned Line;
if (!LineTable.getLine(RealInst, Line)) {
// Instruction has no line, it may have been removed (in the module that
// will be passed to the debugger) so there is nothing to do here.
DEBUG(dbgs() << "WARNING: no LineTable entry for instruction " << RealInst
<< "\n");
DEBUG(RealInst->dump());
return;
}
DebugLoc NewLoc;
if (!Loc.isUnknown())
// I had a previous debug location: re-use the DebugLoc
NewLoc = DebugLoc::get(Line, Col, Loc.getScope(RealInst->getContext()),
Loc.getInlinedAt(RealInst->getContext()));
else if (MDNode *scope = findScope(&I))
NewLoc = DebugLoc::get(Line, Col, scope, nullptr);
else {
DEBUG(dbgs() << "WARNING: no valid scope for instruction " << &I
<< ". no DebugLoc will be present."
<< "\n");
return;
}
addDebugLocation(I, NewLoc);
}
private:
void createCompileUnit(MDNode *CUToReplace) {
std::string Flags;
bool IsOptimized = false;
StringRef Producer;
unsigned RuntimeVersion(0);
StringRef SplitName;
if (CUToReplace) {
// save fields from existing CU to re-use in the new CU
DICompileUnit ExistingCU(CUToReplace);
Producer = ExistingCU.getProducer();
IsOptimized = ExistingCU.isOptimized();
Flags = ExistingCU.getFlags();
RuntimeVersion = ExistingCU.getRunTimeVersion();
SplitName = ExistingCU.getSplitDebugFilename();
} else {
Producer =
"LLVM Version " STR(LLVM_VERSION_MAJOR) "." STR(LLVM_VERSION_MINOR);
}
CUNode =
Builder.createCompileUnit(dwarf::DW_LANG_C99, Filename, Directory,
Producer, IsOptimized, Flags, RuntimeVersion);
if (CUToReplace)
CUToReplace->replaceAllUsesWith(const_cast<MDNode *>(CUNode));
DICompileUnit CU(CUNode);
FileNode = Builder.createFile(Filename, Directory);
LexicalBlockFileNode = Builder.createLexicalBlockFile(CU, DIFile(FileNode));
}
/// Returns the MDNode* that represents the DI scope to associate with I
MDNode *findScope(const Instruction *I) {
const Function *F = I->getParent()->getParent();
if (MDNode *ret = findDISubprogram(F))
return ret;
DEBUG(dbgs() << "WARNING: Using fallback lexical block file scope "
<< LexicalBlockFileNode << " as scope for instruction " << I
<< "\n");
return LexicalBlockFileNode;
}
/// Returns the MDNode* that is the descriptor for F
MDNode *findDISubprogram(const Function *F) {
typedef ValueMap<const Function *, MDNode *>::const_iterator FuncNodeIter;
FuncNodeIter i = SubprogramDescriptors.find(F);
if (i != SubprogramDescriptors.end())
return i->second;
DEBUG(dbgs() << "searching for DI scope node for Function " << F
<< " in a list of " << Finder.subprogram_count()
<< " subprogram nodes"
<< "\n");
for (DISubprogram S : Finder.subprograms()) {
if (S.getFunction() == F) {
DEBUG(dbgs() << "Found DISubprogram " << S << " for function "
<< S.getFunction() << "\n");
return S;
}
}
DEBUG(dbgs() << "unable to find DISubprogram node for function "
<< F->getName().str() << "\n");
return nullptr;
}
/// Sets Line to the line number on which V appears and returns true. If a
/// line location for V is not found, returns false.
bool findLine(const Value *V, unsigned &Line) {
if (LineTable.getLine(V, Line))
return true;
if (VMap) {
Value *mapped = VMap->lookup(V);
if (mapped && LineTable.getLine(mapped, Line))
return true;
}
return false;
}
std::string getTypeName(Type *T) {
std::string TypeName;
raw_string_ostream TypeStream(TypeName);
if (T)
T->print(TypeStream);
else
TypeStream << "Printing <null> Type";
TypeStream.flush();
return TypeName;
}
/// Returns the MDNode that represents type T if it is already created, or 0
/// if it is not.
MDNode *getType(const Type *T) {
typedef DenseMap<const Type *, MDNode *>::const_iterator TypeNodeIter;
TypeNodeIter i = TypeDescriptors.find(T);
if (i != TypeDescriptors.end())
return i->second;
return nullptr;
}
/// Returns a DebugInfo type from an LLVM type T.
DIDerivedType getOrCreateType(Type *T) {
MDNode *N = getType(T);
if (N)
return DIDerivedType(N);
else if (T->isVoidTy())
return DIDerivedType(nullptr);
else if (T->isStructTy()) {
N = Builder.createStructType(
DIScope(LexicalBlockFileNode), T->getStructName(), DIFile(FileNode),
0, Layout.getTypeSizeInBits(T), Layout.getABITypeAlignment(T), 0,
DIType(nullptr), DIArray(nullptr)); // filled in later
// N is added to the map (early) so that element search below can find it,
// so as to avoid infinite recursion for structs that contain pointers to
// their own type.
TypeDescriptors[T] = N;
DICompositeType StructDescriptor(N);
SmallVector<Value *, 4> Elements;
for (unsigned i = 0; i < T->getStructNumElements(); ++i)
Elements.push_back(getOrCreateType(T->getStructElementType(i)));
// set struct elements
StructDescriptor.setTypeArray(Builder.getOrCreateArray(Elements));
} else if (T->isPointerTy()) {
Type *PointeeTy = T->getPointerElementType();
if (!(N = getType(PointeeTy)))
N = Builder.createPointerType(
getOrCreateType(PointeeTy), Layout.getPointerTypeSizeInBits(T),
Layout.getPrefTypeAlignment(T), getTypeName(T));
} else if (T->isArrayTy()) {
SmallVector<Value *, 1> Subrange;
Subrange.push_back(
Builder.getOrCreateSubrange(0, T->getArrayNumElements() - 1));
N = Builder.createArrayType(Layout.getTypeSizeInBits(T),
Layout.getPrefTypeAlignment(T),
getOrCreateType(T->getArrayElementType()),
Builder.getOrCreateArray(Subrange));
} else {
int encoding = llvm::dwarf::DW_ATE_signed;
if (T->isIntegerTy())
encoding = llvm::dwarf::DW_ATE_unsigned;
else if (T->isFloatingPointTy())
encoding = llvm::dwarf::DW_ATE_float;
N = Builder.createBasicType(getTypeName(T), T->getPrimitiveSizeInBits(),
0, encoding);
}
TypeDescriptors[T] = N;
return DIDerivedType(N);
}
/// Returns a DebugInfo type that represents a function signature for Func.
DICompositeType createFunctionSignature(const Function *Func) {
SmallVector<Value *, 4> Params;
DIDerivedType ReturnType(getOrCreateType(Func->getReturnType()));
Params.push_back(ReturnType);
const Function::ArgumentListType &Args(Func->getArgumentList());
for (Function::ArgumentListType::const_iterator i = Args.begin(),
e = Args.end();
i != e; ++i) {
Type *T(i->getType());
Params.push_back(getOrCreateType(T));
}
DIArray ParamArray = Builder.getOrCreateArray(Params);
return Builder.createSubroutineType(DIFile(FileNode), ParamArray);
}
/// Associates Instruction I with debug location Loc.
void addDebugLocation(Instruction &I, DebugLoc Loc) {
MDNode *MD = Loc.getAsMDNode(I.getContext());
I.setMetadata(LLVMContext::MD_dbg, MD);
}
};
/// Sets Filename/Directory from the Module identifier and returns true, or
/// false if source information is not present.
bool getSourceInfoFromModule(const Module &M, std::string &Directory,
std::string &Filename) {
std::string PathStr(M.getModuleIdentifier());
if (PathStr.length() == 0 || PathStr == "<stdin>")
return false;
Filename = sys::path::filename(PathStr);
SmallVector<char, 16> Path(PathStr.begin(), PathStr.end());
sys::path::remove_filename(Path);
Directory = StringRef(Path.data(), Path.size());
return true;
}
// Sets Filename/Directory from debug information in M and returns true, or
// false if no debug information available, or cannot be parsed.
bool getSourceInfoFromDI(const Module &M, std::string &Directory,
std::string &Filename) {
NamedMDNode *CUNode = M.getNamedMetadata("llvm.dbg.cu");
if (!CUNode || CUNode->getNumOperands() == 0)
return false;
DICompileUnit CU(CUNode->getOperand(0));
if (!CU.Verify())
return false;
Filename = CU.getFilename();
Directory = CU.getDirectory();
return true;
}
} // anonymous namespace
namespace llvm {
bool DebugIR::getSourceInfo(const Module &M) {
ParsedPath = getSourceInfoFromDI(M, Directory, Filename) ||
getSourceInfoFromModule(M, Directory, Filename);
return ParsedPath;
}
bool DebugIR::updateExtension(StringRef NewExtension) {
size_t dot = Filename.find_last_of(".");
if (dot == std::string::npos)
return false;
Filename.erase(dot);
Filename += NewExtension.str();
return true;
}
void DebugIR::generateFilename(std::unique_ptr<int> &fd) {
SmallVector<char, 16> PathVec;
fd.reset(new int);
sys::fs::createTemporaryFile("debug-ir", "ll", *fd, PathVec);
StringRef Path(PathVec.data(), PathVec.size());
Filename = sys::path::filename(Path);
sys::path::remove_filename(PathVec);
Directory = StringRef(PathVec.data(), PathVec.size());
GeneratedPath = true;
}
std::string DebugIR::getPath() {
SmallVector<char, 16> Path;
sys::path::append(Path, Directory, Filename);
Path.resize(Filename.size() + Directory.size() + 2);
Path[Filename.size() + Directory.size() + 1] = '\0';
return std::string(Path.data());
}
void DebugIR::writeDebugBitcode(const Module *M, int *fd) {
std::unique_ptr<raw_fd_ostream> Out;
std::string error;
if (!fd) {
std::string Path = getPath();
Out.reset(new raw_fd_ostream(Path.c_str(), error, sys::fs::F_Text));
DEBUG(dbgs() << "WRITING debug bitcode from Module " << M << " to file "
<< Path << "\n");
} else {
DEBUG(dbgs() << "WRITING debug bitcode from Module " << M << " to fd "
<< *fd << "\n");
Out.reset(new raw_fd_ostream(*fd, true));
}
M->print(*Out, nullptr);
Out->close();
}
void DebugIR::createDebugInfo(Module &M, std::unique_ptr<Module> &DisplayM) {
if (M.getFunctionList().size() == 0)
// no functions -- no debug info needed
return;
std::unique_ptr<ValueToValueMapTy> VMap;
if (WriteSourceToDisk && (HideDebugIntrinsics || HideDebugMetadata)) {
VMap.reset(new ValueToValueMapTy);
DisplayM.reset(CloneModule(&M, *VMap));
if (HideDebugIntrinsics)
DebugIntrinsicsRemover::process(*DisplayM);
if (HideDebugMetadata)
DebugMetadataRemover::process(*DisplayM);
}
DIUpdater R(M, Filename, Directory, DisplayM.get(), VMap.get());
}
bool DebugIR::isMissingPath() { return Filename.empty() || Directory.empty(); }
bool DebugIR::runOnModule(Module &M) {
std::unique_ptr<int> fd;
if (isMissingPath() && !getSourceInfo(M)) {
if (!WriteSourceToDisk)
report_fatal_error("DebugIR unable to determine file name in input. "
"Ensure Module contains an identifier, a valid "
"DICompileUnit, or construct DebugIR with "
"non-empty Filename/Directory parameters.");
else
generateFilename(fd);
}
if (!GeneratedPath && WriteSourceToDisk)
updateExtension(".debug-ll");
// Clear line numbers. Keep debug info (if any) if we were able to read the
// file name from the DICompileUnit descriptor.
DebugMetadataRemover::process(M, !ParsedPath);
std::unique_ptr<Module> DisplayM;
createDebugInfo(M, DisplayM);
if (WriteSourceToDisk) {
Module *OutputM = DisplayM.get() ? DisplayM.get() : &M;
writeDebugBitcode(OutputM, fd.get());
}
DEBUG(M.dump());
return true;
}
bool DebugIR::runOnModule(Module &M, std::string &Path) {
bool result = runOnModule(M);
Path = getPath();
return result;
}
} // llvm namespace
char DebugIR::ID = 0;
INITIALIZE_PASS(DebugIR, "debug-ir", "Enable debugging IR", false, false)
ModulePass *llvm::createDebugIRPass(bool HideDebugIntrinsics,
bool HideDebugMetadata, StringRef Directory,
StringRef Filename) {
return new DebugIR(HideDebugIntrinsics, HideDebugMetadata, Directory,
Filename);
}
ModulePass *llvm::createDebugIRPass() { return new DebugIR(); }