Set up MachineDebugInfo to scan for debug information form "llvm.db"g globals.

Global Variable information is now pulled from "llvm.dbg.globals"


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25655 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/MachineDebugInfo.cpp

@@ -9,6 +9,13 @@
 
 #include "llvm/CodeGen/MachineDebugInfo.h"
 
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Support/Dwarf.h"
+
 using namespace llvm;
 
 // Handle the Pass registration stuff necessary to use TargetData's.
@@ -16,8 +23,220 @@ namespace {
   RegisterPass<MachineDebugInfo> X("machinedebuginfo", "Debug Information");
 }
 
+//===----------------------------------------------------------------------===//
+
+/// getGlobalVariablesUsing - Return all of the global variables which have the
+/// specified value in their initializer somewhere.
+static void
+getGlobalVariablesUsing(Value *V, std::vector<GlobalVariable*> &Result) {
+  // Scan though value users.
+  for (Value::use_iterator I = V->use_begin(), E = V->use_end(); I != E; ++I) {
+    if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*I)) {
+      // If the user is a global variable then add to result.
+      Result.push_back(GV);
+    } else if (Constant *C = dyn_cast<Constant>(*I)) {
+      // If the user is a constant variable then scan its users
+      getGlobalVariablesUsing(C, Result);
+    }
+  }
+}
+
+/// getGlobalVariablesUsing - Return all of the global variables that use the
+/// named global variable.
+static std::vector<GlobalVariable*>
+getGlobalVariablesUsing(Module &M, const std::string &RootName) {
+  std::vector<GlobalVariable*> Result;  // Global variables matching criteria.
+
+  // Get the global variable root.
+  GlobalVariable *UseRoot = M.getGlobalVariable(RootName,
+                                   StructType::get(std::vector<const Type*>()));
+
+  // If present and linkonce then scan for users.
+  if (UseRoot && UseRoot->hasLinkOnceLinkage()) {
+    getGlobalVariablesUsing(UseRoot, Result);
+  }
+  
+  return Result;
+}
+  
+/// getStringValue - Turn an LLVM constant pointer that eventually points to a
+/// global into a string value.  Return an empty string if we can't do it.
+///
+const static std::string getStringValue(Value *V, unsigned Offset = 0) {
+  if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
+    if (GV->hasInitializer() && isa<ConstantArray>(GV->getInitializer())) {
+      ConstantArray *Init = cast<ConstantArray>(GV->getInitializer());
+      if (Init->isString()) {
+        std::string Result = Init->getAsString();
+        if (Offset < Result.size()) {
+          // If we are pointing INTO The string, erase the beginning...
+          Result.erase(Result.begin(), Result.begin()+Offset);
+
+          // Take off the null terminator, and any string fragments after it.
+          std::string::size_type NullPos = Result.find_first_of((char)0);
+          if (NullPos != std::string::npos)
+            Result.erase(Result.begin()+NullPos, Result.end());
+          return Result;
+        }
+      }
+    }
+  } else if (Constant *C = dyn_cast<Constant>(V)) {
+    if (GlobalValue *GV = dyn_cast<GlobalValue>(C))
+      return getStringValue(GV, Offset);
+    else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C)) {
+      if (CE->getOpcode() == Instruction::GetElementPtr) {
+        // Turn a gep into the specified offset.
+        if (CE->getNumOperands() == 3 &&
+            cast<Constant>(CE->getOperand(1))->isNullValue() &&
+            isa<ConstantInt>(CE->getOperand(2))) {
+          return getStringValue(CE->getOperand(0),
+                   Offset+cast<ConstantInt>(CE->getOperand(2))->getRawValue());
+        }
+      }
+    }
+  }
+  return "";
+}
   
 //===----------------------------------------------------------------------===//
+
+DebugInfoWrapper::DebugInfoWrapper(GlobalVariable *G)
+: GV(G)
+, IC(dyn_cast<ConstantStruct>(GV->getInitializer())) {
+  assert(IC && "llvm.db.global is missing structured constant");
+}
+  
+//===----------------------------------------------------------------------===//
+
+CompileUnitWrapper::CompileUnitWrapper(GlobalVariable *G)
+: DebugInfoWrapper(G)
+{
+  // FIXME - should probably ease up on the number of operands (version.)
+  assert(IC->getNumOperands() == 7 &&
+         "Compile unit does not have correct number of operands");
+}
+
+/// getTag - Return the compile unit's tag number.  Currently should be 
+/// DW_TAG_variable.
+unsigned CompileUnitWrapper::getTag() const {
+  ConstantUInt *CI = dyn_cast<ConstantUInt>(IC->getOperand(0));
+  assert(CI && "Compile unit tag not an unsigned integer");
+  return CI->getValue();
+}
+
+/// isCorrectDebugVersion - Return true if is the correct llvm debug version.
+/// Currently the value is 0 (zero.)  If the value is is not correct then
+/// ignore all debug information.
+bool CompileUnitWrapper::isCorrectDebugVersion() const {
+  ConstantUInt *CI = dyn_cast<ConstantUInt>(IC->getOperand(1));
+  assert(CI && "Compile unit debug version not an unsigned integer");
+  return CI->getValue() == 0;
+}
+
+/// getLanguage - Return the compile unit's language number (ex. DW_LANG_C89.)
+///
+unsigned CompileUnitWrapper::getLanguage() const {
+  ConstantUInt *CI = dyn_cast<ConstantUInt>(IC->getOperand(2));
+  assert(CI && "Compile unit language number not an unsigned integer");
+  return CI->getValue();
+}
+
+/// getFileName - Return the compile unit's file name.
+///
+const std::string CompileUnitWrapper::getFileName() const {
+  return getStringValue(IC->getOperand(3));
+}
+
+/// getDirectory - Return the compile unit's file directory.
+///
+const std::string CompileUnitWrapper::getDirectory() const {
+  return getStringValue(IC->getOperand(4));
+}
+  
+/// getProducer - Return the compile unit's generator name.
+///
+const std::string CompileUnitWrapper::getProducer() const {
+  return getStringValue(IC->getOperand(5));
+}
+
+//===----------------------------------------------------------------------===//
+
+GlobalWrapper::GlobalWrapper(GlobalVariable *G)
+: DebugInfoWrapper(G)
+{
+  // FIXME - should probably ease up on the number of operands (version.)
+  assert(IC->getNumOperands() == 8 &&
+         "Global does not have correct number of operands");
+}
+
+/// getTag - Return the global's tag number.  Currently should be 
+/// DW_TAG_variable or DW_TAG_subprogram.
+unsigned GlobalWrapper::getTag() const {
+  ConstantUInt *CI = dyn_cast<ConstantUInt>(IC->getOperand(0));
+  assert(CI && "Global tag not an unsigned integer");
+  return CI->getValue();
+}
+
+/// getContext - Return the "lldb.compile_unit" context global.
+///
+GlobalVariable *GlobalWrapper::getContext() const {
+  return dyn_cast<GlobalVariable>(IC->getOperand(1));
+}
+
+/// getName - Return the name of the global.
+///
+const std::string GlobalWrapper::getName() const {
+  return getStringValue(IC->getOperand(2));
+}
+
+/// getType - Return the type of the global.
+///
+const GlobalVariable *GlobalWrapper::getType() const {
+  return dyn_cast<GlobalVariable>(IC->getOperand(4));
+}
+
+/// isStatic - Return true if the global is static.
+///
+bool GlobalWrapper::isStatic() const {
+  ConstantBool *CB = dyn_cast<ConstantBool>(IC->getOperand(5));
+  assert(CB && "Global static flag is not boolean");
+  return CB->getValue();
+}
+
+/// isDefinition - Return true if the global is a definition.
+///
+bool GlobalWrapper::isDefinition() const {
+  ConstantBool *CB = dyn_cast<ConstantBool>(IC->getOperand(6));
+  assert(CB && "Global definition flag is not boolean");
+  return CB->getValue();
+}
+
+/// getGlobalVariable - Return the global variable (tag == DW_TAG_variable.)
+///
+GlobalVariable *GlobalWrapper::getGlobalVariable() const {
+  ConstantExpr *CE = dyn_cast<ConstantExpr>(IC->getOperand(7));
+  assert(CE && CE->getOpcode() == Instruction::Cast &&
+         "Global location is not a cast of GlobalVariable");
+  GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0));
+  assert(GV && "Global location is not a cast of GlobalVariable");
+  return GV;
+}
+
+//===----------------------------------------------------------------------===//
+
+
+MachineDebugInfo::MachineDebugInfo()
+: CompileUnits()
+, Directories()
+, SourceFiles()
+, Lines()
+{
+  
+}
+MachineDebugInfo::~MachineDebugInfo() {
+
+}
+
 /// doInitialization - Initialize the debug state for a new module.
 ///
 bool MachineDebugInfo::doInitialization() {
@@ -29,3 +248,53 @@ bool MachineDebugInfo::doInitialization() {
 bool MachineDebugInfo::doFinalization() {
   return false;
 }
+
+/// AnalyzeModule - Scan the module for global debug information.
+///
+void MachineDebugInfo::AnalyzeModule(Module &M) {
+  SetupCompileUnits(M);
+}
+
+/// SetupCompileUnits - Set up the unique vector of compile units.
+///
+void MachineDebugInfo::SetupCompileUnits(Module &M) {
+  // Get vector of all debug compile units.
+  std::vector<GlobalVariable*> Globals =
+                       getGlobalVariablesUsing(M, "llvm.dbg.translation_units");
+  
+  // Scan all compile unit globals.
+  for (unsigned i = 0, N = Globals.size(); i < N; ++i) {
+    // Create wrapper for compile unit.
+    CompileUnitWrapper CUI(Globals[i]);
+    // Add to result.
+    if (CUI.isCorrectDebugVersion()) CompileUnits.insert(CUI);
+  }
+  
+  // If there any bad compile units then suppress debug information
+  if (CompileUnits.size() != Globals.size()) CompileUnits.reset();
+}
+
+/// getGlobalVariables - Return a vector of debug global variables.
+///
+std::vector<GlobalWrapper> MachineDebugInfo::getGlobalVariables(Module &M) {
+  // Get vector of all debug global objects.
+  std::vector<GlobalVariable*> Globals =
+                                 getGlobalVariablesUsing(M, "llvm.dbg.globals");
+  
+  // Accumulation of global variables.
+  std::vector<GlobalWrapper> GlobalVariables;
+
+// FIXME - skip until globals have new format
+#if 0
+  // Scan all globals.
+  for (unsigned i = 0, N = Globals.size(); i < N; ++i) {
+    // Create wrapper for global.
+    GlobalWrapper GW(Globals[i]);
+    // If the global is a variable then add to result.
+    if (GW.getTag() == DW_TAG_variable) GlobalVariables.push_back(GW);
+  }
+#endif
+
+  return GlobalVariables;
+}
+