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

6 files changed, 417 insertions, 437 deletions

diff --git a/include/llvm/CodeGen/DwarfWriter.h b/include/llvm/CodeGen/DwarfWriter.h
index bf5c098..f199dd2 100644
--- a/include/llvm/CodeGen/DwarfWriter.h
+++ b/include/llvm/CodeGen/DwarfWriter.h
@@ -27,415 +27,6 @@
 
 
 namespace llvm {
-
-  //===--------------------------------------------------------------------===//
-  // Dwarf constants as gleaned from the DWARF Debugging Information Format V.3
-  // reference manual http://dwarf.freestandards.org .
-  //
-  enum dwarf_constants {
-    DWARF_VERSION = 2,
-    
-   // Tags
-    DW_TAG_array_type = 0x01,
-    DW_TAG_class_type = 0x02,
-    DW_TAG_entry_point = 0x03,
-    DW_TAG_enumeration_type = 0x04,
-    DW_TAG_formal_parameter = 0x05,
-    DW_TAG_imported_declaration = 0x08,
-    DW_TAG_label = 0x0a,
-    DW_TAG_lexical_block = 0x0b,
-    DW_TAG_member = 0x0d,
-    DW_TAG_pointer_type = 0x0f,
-    DW_TAG_reference_type = 0x10,
-    DW_TAG_compile_unit = 0x11,
-    DW_TAG_string_type = 0x12,
-    DW_TAG_structure_type = 0x13,
-    DW_TAG_subroutine_type = 0x15,
-    DW_TAG_typedef = 0x16,
-    DW_TAG_union_type = 0x17,
-    DW_TAG_unspecified_parameters = 0x18,
-    DW_TAG_variant = 0x19,
-    DW_TAG_common_block = 0x1a,
-    DW_TAG_common_inclusion = 0x1b,
-    DW_TAG_inheritance = 0x1c,
-    DW_TAG_inlined_subroutine = 0x1d,
-    DW_TAG_module = 0x1e,
-    DW_TAG_ptr_to_member_type = 0x1f,
-    DW_TAG_set_type = 0x20,
-    DW_TAG_subrange_type = 0x21,
-    DW_TAG_with_stmt = 0x22,
-    DW_TAG_access_declaration = 0x23,
-    DW_TAG_base_type = 0x24,
-    DW_TAG_catch_block = 0x25,
-    DW_TAG_const_type = 0x26,
-    DW_TAG_constant = 0x27,
-    DW_TAG_enumerator = 0x28,
-    DW_TAG_file_type = 0x29,
-    DW_TAG_friend = 0x2a,
-    DW_TAG_namelist = 0x2b,
-    DW_TAG_namelist_item = 0x2c,
-    DW_TAG_packed_type = 0x2d,
-    DW_TAG_subprogram = 0x2e,
-    DW_TAG_template_type_parameter = 0x2f,
-    DW_TAG_template_value_parameter = 0x30,
-    DW_TAG_thrown_type = 0x31,
-    DW_TAG_try_block = 0x32,
-    DW_TAG_variant_part = 0x33,
-    DW_TAG_variable = 0x34,
-    DW_TAG_volatile_type = 0x35,
-    DW_TAG_dwarf_procedure = 0x36,
-    DW_TAG_restrict_type = 0x37,
-    DW_TAG_interface_type = 0x38,
-    DW_TAG_namespace = 0x39,
-    DW_TAG_imported_module = 0x3a,
-    DW_TAG_unspecified_type = 0x3b,
-    DW_TAG_partial_unit = 0x3c,
-    DW_TAG_imported_unit = 0x3d,
-    DW_TAG_condition = 0x3f,
-    DW_TAG_shared_type = 0x40,
-    DW_TAG_lo_user = 0x4080,
-    DW_TAG_hi_user = 0xffff,
-
-    // Children flag
-    DW_CHILDREN_no = 0x00,
-    DW_CHILDREN_yes = 0x01,
-
-    // Attributes
-    DW_AT_sibling = 0x01,
-    DW_AT_location = 0x02,
-    DW_AT_name = 0x03,
-    DW_AT_ordering = 0x09,
-    DW_AT_byte_size = 0x0b,
-    DW_AT_bit_offset = 0x0c,
-    DW_AT_bit_size = 0x0d,
-    DW_AT_stmt_list = 0x10,
-    DW_AT_low_pc = 0x11,
-    DW_AT_high_pc = 0x12,
-    DW_AT_language = 0x13,
-    DW_AT_discr = 0x15,
-    DW_AT_discr_value = 0x16,
-    DW_AT_visibility = 0x17,
-    DW_AT_import = 0x18,
-    DW_AT_string_length = 0x19,
-    DW_AT_common_reference = 0x1a,
-    DW_AT_comp_dir = 0x1b,
-    DW_AT_const_value = 0x1c,
-    DW_AT_containing_type = 0x1d,
-    DW_AT_default_value = 0x1e,
-    DW_AT_inline = 0x20,
-    DW_AT_is_optional = 0x21,
-    DW_AT_lower_bound = 0x22,
-    DW_AT_producer = 0x25,
-    DW_AT_prototyped = 0x27,
-    DW_AT_return_addr = 0x2a,
-    DW_AT_start_scope = 0x2c,
-    DW_AT_bit_stride = 0x2e,
-    DW_AT_upper_bound = 0x2f,
-    DW_AT_abstract_origin = 0x31,
-    DW_AT_accessibility = 0x32,
-    DW_AT_address_class = 0x33,
-    DW_AT_artificial = 0x34,
-    DW_AT_base_types = 0x35,
-    DW_AT_calling_convention = 0x36,
-    DW_AT_count = 0x37,
-    DW_AT_data_member_location = 0x38,
-    DW_AT_decl_column = 0x39,
-    DW_AT_decl_file = 0x3a,
-    DW_AT_decl_line = 0x3b,
-    DW_AT_declaration = 0x3c,
-    DW_AT_discr_list = 0x3d,
-    DW_AT_encoding = 0x3e,
-    DW_AT_external = 0x3f,
-    DW_AT_frame_base = 0x40,
-    DW_AT_friend = 0x41,
-    DW_AT_identifier_case = 0x42,
-    DW_AT_macro_info = 0x43,
-    DW_AT_namelist_item = 0x44,
-    DW_AT_priority = 0x45,
-    DW_AT_segment = 0x46,
-    DW_AT_specification = 0x47,
-    DW_AT_static_link = 0x48,
-    DW_AT_type = 0x49,
-    DW_AT_use_location = 0x4a,
-    DW_AT_variable_parameter = 0x4b,
-    DW_AT_virtuality = 0x4c,
-    DW_AT_vtable_elem_location = 0x4d,
-    DW_AT_allocated = 0x4e,
-    DW_AT_associated = 0x4f,
-    DW_AT_data_location = 0x50,
-    DW_AT_byte_stride = 0x51,
-    DW_AT_entry_pc = 0x52,
-    DW_AT_use_UTF8 = 0x53,
-    DW_AT_extension = 0x54,
-    DW_AT_ranges = 0x55,
-    DW_AT_trampoline = 0x56,
-    DW_AT_call_column = 0x57,
-    DW_AT_call_file = 0x58,
-    DW_AT_call_line = 0x59,
-    DW_AT_description = 0x5a,
-    DW_AT_binary_scale = 0x5b,
-    DW_AT_decimal_scale = 0x5c,
-    DW_AT_small = 0x5d,
-    DW_AT_decimal_sign = 0x5e,
-    DW_AT_digit_count = 0x5f,
-    DW_AT_picture_string = 0x60,
-    DW_AT_mutable = 0x61,
-    DW_AT_threads_scaled = 0x62,
-    DW_AT_explicit = 0x63,
-    DW_AT_object_pointer = 0x64,
-    DW_AT_endianity = 0x65,
-    DW_AT_elemental = 0x66,
-    DW_AT_pure = 0x67,
-    DW_AT_recursive = 0x68,
-    DW_AT_lo_user = 0x2000,
-    DW_AT_hi_user = 0x3fff,
-
-    // Attribute form encodings
-    DW_FORM_addr = 0x01,
-    DW_FORM_block2 = 0x03,
-    DW_FORM_block4 = 0x04,
-    DW_FORM_data2 = 0x05,
-    DW_FORM_data4 = 0x06,
-    DW_FORM_data8 = 0x07,
-    DW_FORM_string = 0x08,
-    DW_FORM_block = 0x09,
-    DW_FORM_block1 = 0x0a,
-    DW_FORM_data1 = 0x0b,
-    DW_FORM_flag = 0x0c,
-    DW_FORM_sdata = 0x0d,
-    DW_FORM_strp = 0x0e,
-    DW_FORM_udata = 0x0f,
-    DW_FORM_ref_addr = 0x10,
-    DW_FORM_ref1 = 0x11,
-    DW_FORM_ref2 = 0x12,
-    DW_FORM_ref4 = 0x13,
-    DW_FORM_ref8 = 0x14,
-    DW_FORM_ref_udata = 0x15,
-    DW_FORM_indirect = 0x16,
-
-    // Operation encodings
-    DW_OP_addr = 0x03,
-    DW_OP_deref = 0x06,
-    DW_OP_const1u = 0x08,
-    DW_OP_const1s = 0x09,
-    DW_OP_const2u = 0x0a,
-    DW_OP_const2s = 0x0b,
-    DW_OP_const4u = 0x0c,
-    DW_OP_const4s = 0x0d,
-    DW_OP_const8u = 0x0e,
-    DW_OP_const8s = 0x0f,
-    DW_OP_constu = 0x10,
-    DW_OP_consts = 0x11,
-    DW_OP_dup = 0x12,
-    DW_OP_drop = 0x13,
-    DW_OP_over = 0x14,
-    DW_OP_pick = 0x15,
-    DW_OP_swap = 0x16,
-    DW_OP_rot = 0x17,
-    DW_OP_xderef = 0x18,
-    DW_OP_abs = 0x19,
-    DW_OP_and = 0x1a,
-    DW_OP_div = 0x1b,
-    DW_OP_minus = 0x1c,
-    DW_OP_mod = 0x1d,
-    DW_OP_mul = 0x1e,
-    DW_OP_neg = 0x1f,
-    DW_OP_not = 0x20,
-    DW_OP_or = 0x21,
-    DW_OP_plus = 0x22,
-    DW_OP_plus_uconst = 0x23,
-    DW_OP_shl = 0x24,
-    DW_OP_shr = 0x25,
-    DW_OP_shra = 0x26,
-    DW_OP_xor = 0x27,
-    DW_OP_skip = 0x2f,
-    DW_OP_bra = 0x28,
-    DW_OP_eq = 0x29,
-    DW_OP_ge = 0x2a,
-    DW_OP_gt = 0x2b,
-    DW_OP_le = 0x2c,
-    DW_OP_lt = 0x2d,
-    DW_OP_ne = 0x2e,
-    DW_OP_lit0 = 0x30,
-    DW_OP_lit1 = 0x31,
-    DW_OP_lit31 = 0x4f,
-    DW_OP_reg0 = 0x50,
-    DW_OP_reg1 = 0x51,
-    DW_OP_reg31 = 0x6f,
-    DW_OP_breg0 = 0x70,
-    DW_OP_breg1 = 0x71,
-    DW_OP_breg31 = 0x8f,
-    DW_OP_regx = 0x90,
-    DW_OP_fbreg = 0x91,
-    DW_OP_bregx = 0x92,
-    DW_OP_piece = 0x93,
-    DW_OP_deref_size = 0x94,
-    DW_OP_xderef_size = 0x95,
-    DW_OP_nop = 0x96,
-    DW_OP_push_object_address = 0x97,
-    DW_OP_call2 = 0x98,
-    DW_OP_call4 = 0x99,
-    DW_OP_call_ref = 0x9a,
-    DW_OP_form_tls_address = 0x9b,
-    DW_OP_call_frame_cfa = 0x9c,
-    DW_OP_lo_user = 0xe0,
-    DW_OP_hi_user = 0xff,
-
-    // Encoding attribute values
-    DW_ATE_address = 0x01,
-    DW_ATE_boolean = 0x02,
-    DW_ATE_complex_float = 0x03,
-    DW_ATE_float = 0x04,
-    DW_ATE_signed = 0x05,
-    DW_ATE_signed_char = 0x06,
-    DW_ATE_unsigned = 0x07,
-    DW_ATE_unsigned_char = 0x08,
-    DW_ATE_imaginary_float = 0x09,
-    DW_ATE_packed_decimal = 0x0a,
-    DW_ATE_numeric_string = 0x0b,
-    DW_ATE_edited = 0x0c,
-    DW_ATE_signed_fixed = 0x0d,
-    DW_ATE_unsigned_fixed = 0x0e,
-    DW_ATE_decimal_float = 0x0f,
-    DW_ATE_lo_user = 0x80,
-    DW_ATE_hi_user = 0xff,
-
-    // Decimal sign attribute values
-    DW_DS_unsigned = 0x01,
-    DW_DS_leading_overpunch = 0x02,
-    DW_DS_trailing_overpunch = 0x03,
-    DW_DS_leading_separate = 0x04,
-    DW_DS_trailing_separate = 0x05,
-
-    // Endianity attribute values
-    DW_END_default = 0x00,
-    DW_END_big = 0x01,
-    DW_END_little = 0x02,
-    DW_END_lo_user = 0x40,
-    DW_END_hi_user = 0xff,
-
-    // Accessibility codes
-    DW_ACCESS_public = 0x01,
-    DW_ACCESS_protected = 0x02,
-    DW_ACCESS_private = 0x03,
-
-    // Visibility codes 
-    DW_VIS_local = 0x01,
-    DW_VIS_exported = 0x02,
-    DW_VIS_qualified = 0x03,
-
-    // Virtuality codes
-    DW_VIRTUALITY_none = 0x00,
-    DW_VIRTUALITY_virtual = 0x01,
-    DW_VIRTUALITY_pure_virtual = 0x02,
-    
-    // Language names
-    DW_LANG_C89 = 0x0001,
-    DW_LANG_C = 0x0002,
-    DW_LANG_Ada83 = 0x0003,
-    DW_LANG_C_plus_plus = 0x0004,
-    DW_LANG_Cobol74 = 0x0005,
-    DW_LANG_Cobol85 = 0x0006,
-    DW_LANG_Fortran77 = 0x0007,
-    DW_LANG_Fortran90 = 0x0008,
-    DW_LANG_Pascal83 = 0x0009,
-    DW_LANG_Modula2 = 0x000a,
-    DW_LANG_Java = 0x000b,
-    DW_LANG_C99 = 0x000c,
-    DW_LANG_Ada95 = 0x000d,
-    DW_LANG_Fortran95 = 0x000e,
-    DW_LANG_PLI = 0x000f,
-    DW_LANG_ObjC = 0x0010,
-    DW_LANG_ObjC_plus_plus = 0x0011,
-    DW_LANG_UPC = 0x0012,
-    DW_LANG_D = 0x0013,
-    DW_LANG_lo_user = 0x8000,
-    DW_LANG_hi_user = 0xffff,
-    
-    // Identifier case codes
-    DW_ID_case_sensitive = 0x00,
-    DW_ID_up_case = 0x01,
-    DW_ID_down_case = 0x02,
-    DW_ID_case_insensitive = 0x03,
-
-    // Calling convention codes
-    DW_CC_normal = 0x01,
-    DW_CC_program = 0x02,
-    DW_CC_nocall = 0x03,
-    DW_CC_lo_user = 0x40,
-    DW_CC_hi_user = 0xff,
-
-    // Inline codes
-    DW_INL_not_inlined = 0x00,
-    DW_INL_inlined = 0x01,
-    DW_INL_declared_not_inlined = 0x02,
-    DW_INL_declared_inlined = 0x03,
-
-    // Array ordering 
-    DW_ORD_row_major = 0x00,
-    DW_ORD_col_major = 0x01,
-
-    // Discriminant descriptor values
-    DW_DSC_label = 0x00,
-    DW_DSC_range = 0x01,
-
-    // Line Number Standard Opcode Encodings
-    DW_LNS_copy = 0x01,
-    DW_LNS_advance_pc = 0x02,
-    DW_LNS_advance_line = 0x03,
-    DW_LNS_set_file = 0x04,
-    DW_LNS_set_column = 0x05,
-    DW_LNS_negate_stmt = 0x06,
-    DW_LNS_set_basic_block = 0x07,
-    DW_LNS_const_add_pc = 0x08,
-    DW_LNS_fixed_advance_pc = 0x09,
-    DW_LNS_set_prologue_end = 0x0a,
-    DW_LNS_set_epilogue_begin = 0x0b,
-    DW_LNS_set_isa = 0x0c,
-
-    // Line Number Extended Opcode Encodings
-    DW_LNE_end_sequence = 0x01,
-    DW_LNE_set_address = 0x02,
-    DW_LNE_define_file = 0x03,
-    DW_LNE_lo_user = 0x80,
-    DW_LNE_hi_user = 0xff,
-
-    // Macinfo Type Encodings
-    DW_MACINFO_define = 0x01,
-    DW_MACINFO_undef = 0x02,
-    DW_MACINFO_start_file = 0x03,
-    DW_MACINFO_end_file = 0x04,
-    DW_MACINFO_vendor_ext = 0xff,
-
-    // Call frame instruction encodings
-    DW_CFA_advance_loc = 0x40,
-    DW_CFA_offset = 0x80,
-    DW_CFA_restore = 0xc0,
-    DW_CFA_set_loc = 0x01,
-    DW_CFA_advance_loc1 = 0x02,
-    DW_CFA_advance_loc2 = 0x03,
-    DW_CFA_advance_loc4 = 0x04,
-    DW_CFA_offset_extended = 0x05,
-    DW_CFA_restore_extended = 0x06,
-    DW_CFA_undefined = 0x07,
-    DW_CFA_same_value = 0x08,
-    DW_CFA_register = 0x09,
-    DW_CFA_remember_state = 0x0a,
-    DW_CFA_restore_state = 0x0b,
-    DW_CFA_def_cfa = 0x0c,
-    DW_CFA_def_cfa_register = 0x0d,
-    DW_CFA_def_cfa_offset = 0x0e,
-    DW_CFA_def_cfa_expression = 0x0f,
-    DW_CFA_expression = 0x10,
-    DW_CFA_offset_extended_sf = 0x11,
-    DW_CFA_def_cfa_sf = 0x12,
-    DW_CFA_def_cfa_offset_sf = 0x13,
-    DW_CFA_val_offset = 0x14,
-    DW_CFA_val_offset_sf = 0x15,
-    DW_CFA_val_expression = 0x16,
-    DW_CFA_lo_user = 0x1c,
-    DW_CFA_hi_user = 0x3f
-  };
   
   //===--------------------------------------------------------------------===//
   // Forward declarations.
diff --git a/include/llvm/CodeGen/MachineDebugInfo.h b/include/llvm/CodeGen/MachineDebugInfo.h
index 5846748..7bbd11d 100644
--- a/include/llvm/CodeGen/MachineDebugInfo.h
+++ b/include/llvm/CodeGen/MachineDebugInfo.h
@@ -39,6 +39,113 @@
 
 namespace llvm {
 
+// Forward declarations.
+class ConstantStruct;
+class GlobalVariable;
+class Module;
+
+//===----------------------------------------------------------------------===//
+/// DebugInfoWrapper - This class is the base class for debug info wrappers.
+///
+class DebugInfoWrapper {
+protected:
+  GlobalVariable *GV;                   // "llvm.db" global
+  ConstantStruct *IC;                   // Initializer constant.
+  
+public:
+  DebugInfoWrapper(GlobalVariable *G);
+  
+  /// getGlobal - Return the "llvm.db" global.
+  ///
+  GlobalVariable *getGlobal() const { return GV; }
+
+  /// operator== - Used by Uniquevector to locate entry.
+  ///
+  bool operator==(const DebugInfoWrapper &DI) const { return IC == DI.IC; }
+
+  /// operator< - Used by Uniquevector to locate entry.
+  ///
+  bool operator<(const DebugInfoWrapper &DI) const { return IC < DI.IC; }
+};
+
+
+//===----------------------------------------------------------------------===//
+/// CompileUnitWrapper - This class wraps a "lldb.compile_unit" global to
+/// provide easy access to its attributes.
+class CompileUnitWrapper : public DebugInfoWrapper {
+public:
+  CompileUnitWrapper(GlobalVariable *G);
+  
+  /// getGlobal - Return the "lldb.compile_unit" global.
+  ///
+  GlobalVariable *getGlobal() const { return GV; }
+
+  /// getTag - Return the compile unit's tag number.  Currently DW_TAG_variable,
+  /// DW_TAG_subprogram or DW_TAG_compile_unit.
+  unsigned getTag() const;
+
+  /// 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 isCorrectDebugVersion() const;
+  
+  /// getLanguage - Return the compile unit's language number (ex. DW_LANG_C89.)
+  ///
+  unsigned getLanguage() const;
+  
+  /// getFileName - Return the compile unit's file name.
+  ///
+  const std::string getFileName() const;
+  
+  /// getDirectory - Return the compile unit's file directory.
+  ///
+  const std::string getDirectory() const;
+  
+  /// getProducer - Return the compile unit's generator name.
+  ///
+  const std::string getProducer() const;
+};
+
+//===----------------------------------------------------------------------===//
+/// GlobalWrapper - This class wraps a "lldb.global" global to provide easy
+/// access to its attributes.
+class GlobalWrapper : public DebugInfoWrapper {
+public:
+  GlobalWrapper(GlobalVariable *G);
+  
+  /// getGlobal - Return the "lldb.global" global.
+  ///
+  GlobalVariable *getGlobal() const { return GV; }
+
+  /// getContext - Return the "lldb.compile_unit" context global.
+  ///
+  GlobalVariable *getContext() const;
+
+  /// getTag - Return the global's tag number.  Currently should be 
+  /// DW_TAG_variable or DW_TAG_subprogram.
+  unsigned getTag() const;
+  
+  /// getName - Return the name of the global.
+  ///
+  const std::string getName() const;
+  
+  /// getType - Return the type of the global.
+  ///
+  const GlobalVariable *getType() const;
+ 
+  /// isStatic - Return true if the global is static.
+  ///
+  bool isStatic() const;
+
+  /// isDefinition - Return true if the global is a definition.
+  ///
+  bool isDefinition() const;
+  
+  /// getGlobalVariable - Return the global variable (tag == DW_TAG_variable.)
+  ///
+  GlobalVariable *getGlobalVariable() const;
+};
+
 //===----------------------------------------------------------------------===//
 /// SourceLineInfo - This class is used to record source line correspondence.
 ///
@@ -94,36 +201,37 @@ public:
 ///
 class MachineDebugInfo : public ImmutablePass {
 private:
-  // DirectoryMap - UniqueVector for directories.
+  // CompileUnits - Uniquing vector for compile units.
+  UniqueVector<CompileUnitWrapper> CompileUnits;
+  
+  // Directories - Uniquing vector for directories.
   UniqueVector<std::string> Directories;
                                          
-  // SourceMap - UniqueVector for source files.
+  // SourceFiles - Uniquing vector for source files.
   UniqueVector<SourceFileInfo> SourceFiles;
 
   // Lines - List of of source line correspondence.
   std::vector<SourceLineInfo *> Lines;
 
 public:
-  MachineDebugInfo()
-  : Directories()
-  , SourceFiles()
-  , Lines()
-  {}
-  ~MachineDebugInfo() { }
+  MachineDebugInfo();
+  ~MachineDebugInfo();
   
   /// doInitialization - Initialize the debug state for a new module.
   ///
   bool doInitialization();
   
-  
   /// doFinalization - Tear down the debug state after completion of a module.
   ///
   bool doFinalization();
   
-  /// hasInfo - Returns true if debug info is present.
+  /// AnalyzeModule - Scan the module for global debug information.
+  ///
+  void AnalyzeModule(Module &M);
+  
+  /// hasInfo - Returns true if valid debug info is present.
   ///
-  // FIXME - need proper scheme to suppress debug output.
-  bool hasInfo() const { return !SourceFiles.empty(); }
+  bool hasInfo() const { return !CompileUnits.empty(); }
   
   /// RecordLabel - Records location information and associates it with a
   /// debug label.  Returns a unique label ID used to generate a label and 
@@ -159,6 +267,14 @@ public:
     return Lines;
   }
   
+  /// SetupCompileUnits - Set up the unique vector of compile units.
+  ///
+  void MachineDebugInfo::SetupCompileUnits(Module &M);
+
+  /// getGlobalVariables - Return a vector of debug global variables.
+  ///
+  static std::vector<GlobalWrapper> getGlobalVariables(Module &M);
+
 }; // End class MachineDebugInfo
 
 } // End llvm namespace
diff --git a/lib/CodeGen/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter.cpp
index 6f216b7c..cafc87e 100644
--- a/lib/CodeGen/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter.cpp
@@ -78,6 +78,11 @@ bool AsmPrinter::doInitialization(Module &M) {
       << "\n" << CommentString << " End of file scope inline assembly\n";
 
   SwitchSection("", 0);   // Reset back to no section.
+  
+  if (MachineDebugInfo *DebugInfo = getAnalysisToUpdate<MachineDebugInfo>()) {
+    DebugInfo->AnalyzeModule(M);
+  }
+  
   return false;
 }
 
diff --git a/lib/CodeGen/DwarfWriter.cpp b/lib/CodeGen/DwarfWriter.cpp
index c11c52f..512f479 100644
--- a/lib/CodeGen/DwarfWriter.cpp
+++ b/lib/CodeGen/DwarfWriter.cpp
@@ -18,6 +18,7 @@
 #include "llvm/Type.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineDebugInfo.h"
+#include "llvm/Support/Dwarf.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/Mangler.h"
 #include "llvm/Target/TargetMachine.h"
@@ -1719,28 +1720,26 @@ void DwarfWriter::ConstructCompileUnitDIEs() {
 /// variables.
 void DwarfWriter::ConstructGlobalDIEs(Module &M) {
   const TargetData &TD = Asm->TM.getTargetData();
-
-  // Iterate throu each of the globals.
-  for (Module::const_global_iterator GI = M.global_begin(), GE = M.global_end();
-       GI != GE; ++GI) {
-    if (!GI->hasInitializer()) continue;   // External global require no code
+  
+  std::vector<GlobalWrapper> GlobalVariables = DebugInfo->getGlobalVariables(M);
+  
+  for (unsigned i = 0, N = GlobalVariables.size(); i < N; ++i) {
+    GlobalWrapper &GW = GlobalVariables[i];
+    GlobalVariable *GV = GW.getGlobalVariable();
     
-    // Check to see if this is a special global used by LLVM, if so, emit it.
-    if (GI->hasAppendingLinkage() && (GI->getName() == "llvm.global_ctors" ||
-                                      GI->getName() == "llvm.global_dtors"))
-      continue;
+    if (!GV->hasInitializer()) continue;   // External global require no code
     
-    std::string Name = Asm->Mang->getValueName(GI);
-    Constant *C = GI->getInitializer();
+    // FIXME - Use global info type information when available.
+    std::string Name = Asm->Mang->getValueName(GV);
+    Constant *C = GV->getInitializer();
     const Type *Ty = C->getType();
     unsigned Size = TD.getTypeSize(Ty);
     unsigned Align = TD.getTypeAlignmentShift(Ty);
 
     if (C->isNullValue() && /* FIXME: Verify correct */
-        (GI->hasInternalLinkage() || GI->hasWeakLinkage() ||
-         GI->hasLinkOnceLinkage())) {
+        (GV->hasInternalLinkage() || GV->hasWeakLinkage() ||
+         GV->hasLinkOnceLinkage())) {
       if (Size == 0) Size = 1;   // .comm Foo, 0 is undefined, avoid it.
-      
     }
 
     /// FIXME - Get correct compile unit context.
@@ -1748,7 +1747,7 @@ void DwarfWriter::ConstructGlobalDIEs(Module &M) {
     DWContext *Context = CompileUnits[0]->getContext();
     
     /// Create new global.
-    NewGlobalVariable(Context, GI->getName(), Name, Ty, Size, Align);
+    NewGlobalVariable(Context, GV->getName(), Name, Ty, Size, Align);
   }
 }
 
diff --git a/lib/CodeGen/MachineDebugInfo.cpp b/lib/CodeGen/MachineDebugInfo.cpp
index 5464686..bfcd981 100644
--- a/lib/CodeGen/MachineDebugInfo.cpp
+++ b/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;
+}
+
diff --git a/lib/Target/PowerPC/PPCAsmPrinter.cpp b/lib/Target/PowerPC/PPCAsmPrinter.cpp
index 0b7ad95..cc74c7d 100644
--- a/lib/Target/PowerPC/PPCAsmPrinter.cpp
+++ b/lib/Target/PowerPC/PPCAsmPrinter.cpp
@@ -431,7 +431,7 @@ void PPCAsmPrinter::printMachineInstruction(const MachineInstr *MI) {
 /// method to print assembly for each instruction.
 ///
 bool DarwinAsmPrinter::runOnMachineFunction(MachineFunction &MF) {
-  // FIXME - is this the earliest this can be set.
+  // FIXME - is this the earliest this can be set?
   DW.SetDebugInfo(&getAnalysis<MachineDebugInfo>());
 
   SetupMachineFunction(MF);