Added -g command line options to clang for generating source level debug information. This patch currently enables generation of line number debug information (stoppoints) and region begin/end debug information. The new files CGDebugInfo.h and CGDebugInfo.cpp implements the debug info manager class CGDebugInfo.

llvm-svn: 50848

clang/lib/CodeGen/CGDebugInfo.cpp

@@ -0,0 +1,171 @@
+//===--- CGDebugInfo.cpp - Emit Debug Information for a Module ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This coordinates the debug information generation while generating code.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CGDebugInfo.h"
+#include "CodeGenModule.h"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Module.h"
+#include "llvm/Support/Dwarf.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Target/TargetMachine.h"
+#include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/CodeGen/MachineModuleInfo.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Basic/FileManager.h"
+#include "clang/AST/ASTContext.h"
+using namespace clang;
+using namespace clang::CodeGen;
+
+CGDebugInfo::CGDebugInfo(CodeGenModule *m)
+: M(m)
+, CurLoc()
+, PrevLoc()
+, CompileUnitCache()
+, StopPointFn(NULL)
+, RegionStartFn(NULL)
+, RegionEndFn(NULL)
+, RegionStack()
+{
+  SR = new llvm::DISerializer();
+  SR->setModule (&M->getModule());
+}
+
+CGDebugInfo::~CGDebugInfo()
+{
+  delete SR;
+}
+
+
+/// getCastValueFor - Return a llvm representation for a given debug information
+/// descriptor cast to an empty struct pointer.
+llvm::Value *CGDebugInfo::getCastValueFor(llvm::DebugInfoDesc *DD) {
+  return llvm::ConstantExpr::getBitCast(SR->Serialize(DD), 
+					SR->getEmptyStructPtrType());
+}
+
+/// getOrCreateCompileUnit - Get the compile unit from the cache or create a new
+/// one if necessary.
+llvm::CompileUnitDesc 
+*CGDebugInfo::getOrCreateCompileUnit(const SourceLocation Loc) {
+
+  // See if this compile unit has been used before.
+  llvm::CompileUnitDesc *&Slot = CompileUnitCache[Loc.getFileID()];
+  if (Slot) return Slot;
+
+  // Create new compile unit.
+  // FIXME: Where to free these?
+  // One way is to iterate over the CompileUnitCache in ~CGDebugInfo.
+  llvm::CompileUnitDesc *Unit = new llvm::CompileUnitDesc();
+
+  // Make sure we have an anchor.
+  if (!CompileUnitAnchor) {
+    CompileUnitAnchor = new llvm::AnchorDesc(Unit);
+  }
+
+  // Get source file information.
+  SourceManager &SM = M->getContext().getSourceManager();
+  const FileEntry *FE = SM.getFileEntryForLoc(Loc);
+  const char *FileName = FE->getName();
+  const char *DirName = FE->getDir()->getName();
+
+  Unit->setAnchor(CompileUnitAnchor);
+  Unit->setFileName(FileName);
+  Unit->setDirectory(DirName);
+
+  // Set up producer name.
+  // FIXME: Do not know how to get clang version yet.
+  Unit->setProducer("clang");
+
+  // Set up Language number.
+  // FIXME: Handle other languages as well.
+  Unit->setLanguage(llvm::dwarf::DW_LANG_C89);
+
+  // Update cache.
+  Slot = Unit;
+
+  return Unit;
+}
+
+
+void 
+CGDebugInfo::EmitStopPoint(llvm::Function *Fn, llvm::IRBuilder &Builder) {
+
+  // Don't bother if things are the same as last time.
+  SourceManager &SM = M->getContext().getSourceManager();
+  if (CurLoc == PrevLoc 
+       || (SM.getLineNumber(CurLoc) == SM.getLineNumber(PrevLoc)
+           && SM.isFromSameFile(CurLoc, PrevLoc)))
+    return;
+  if (CurLoc.isInvalid()) return;
+
+  // Update last state.
+  PrevLoc = CurLoc;
+
+  // Get the appropriate compile unit.
+  llvm::CompileUnitDesc *Unit = getOrCreateCompileUnit(CurLoc);
+
+  // Lazily construct llvm.dbg.stoppoint function.
+  if (!StopPointFn)
+    StopPointFn = llvm::Intrinsic::getDeclaration(&M->getModule(), 
+					llvm::Intrinsic::dbg_stoppoint);
+
+  uint64_t CurLineNo = SM.getLogicalLineNumber(CurLoc);
+  uint64_t ColumnNo = SM.getLogicalColumnNumber(CurLoc);
+
+  // Invoke llvm.dbg.stoppoint
+  Builder.CreateCall3(StopPointFn, 
+		       llvm::ConstantInt::get(llvm::Type::Int32Ty, CurLineNo),
+		       llvm::ConstantInt::get(llvm::Type::Int32Ty, ColumnNo),
+		       getCastValueFor(Unit), "");
+}
+
+/// EmitRegionStart- Constructs the debug code for entering a declarative
+/// region - "llvm.dbg.region.start.".
+void CGDebugInfo::EmitRegionStart(llvm::Function *Fn, llvm::IRBuilder &Builder) 
+{
+  llvm::BlockDesc *Block = new llvm::BlockDesc();
+  if (RegionStack.size() > 0)
+    Block->setContext(RegionStack.back());
+  RegionStack.push_back(Block);
+
+  // Lazily construct llvm.dbg.region.start function.
+  if (!RegionStartFn)
+    RegionStartFn = llvm::Intrinsic::getDeclaration(&M->getModule(), 
+				llvm::Intrinsic::dbg_region_start);
+
+  // Call llvm.dbg.func.start.
+  Builder.CreateCall(RegionStartFn, getCastValueFor(Block), "");
+}
+
+/// EmitRegionEnd - Constructs the debug code for exiting a declarative
+/// region - "llvm.dbg.region.end."
+void CGDebugInfo::EmitRegionEnd(llvm::Function *Fn, llvm::IRBuilder &Builder) 
+{
+  // Lazily construct llvm.dbg.region.end function.
+  if (!RegionEndFn)
+    RegionEndFn =llvm::Intrinsic::getDeclaration(&M->getModule(), 
+				llvm::Intrinsic::dbg_region_end);
+
+  // Provide an region stop point.
+  EmitStopPoint(Fn, Builder);
+  
+  // Call llvm.dbg.func.end.
+  Builder.CreateCall(RegionEndFn, getCastValueFor(RegionStack.back()), "");
+  RegionStack.pop_back();
+  // FIXME: Free here the memory created for BlockDesc in RegionStart?
+}
+