Add support for DW_AT_ranges_base attribute

It is a new attribute emitted by clang as a GNU extension and will
be part of Dwarf5. The purpose of the attribute is to specify a compile
unit level base value for all DW_AT_ranges to reduce the number of
relocations have to be done by the linker.

Fixes (at least partially): https://llvm.org/pr28826

Differential revision: https://reviews.llvm.org/D24514

llvm-svn: 281595

lldb/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/TestSymbolContextTwoFiles.py

@@ -38,3 +38,46 @@ class SymbolContextTwoFilesTestCase(TestBase):
                 symbol_address, lldb.eSymbolContextFunction)
             self.assertEqual(symbol_name,
                              sc_by_address.GetFunction().GetName())
+
+    @add_test_categories(['pyapi'])
+    def test_ranges_in_multiple_compile_unit(self):
+        """This test verifies that we correctly handle the case when multiple
+        compile unit contains DW_AT_ranges and DW_AT_ranges_base attributes."""
+        self.build()
+        exe = os.path.join(os.getcwd(), "a.out")
+
+        target = self.dbg.CreateTarget(exe)
+        self.assertTrue(target, VALID_TARGET)
+
+        source1 = "file1.cpp"
+        line1 = line_number(source1, '// Break1')
+        breakpoint1 = target.BreakpointCreateByLocation(source1, line1)
+        self.assertIsNotNone(breakpoint1)
+        self.assertTrue(breakpoint1.IsValid())
+
+        source2 = "file2.cpp"
+        line2 = line_number(source2, '// Break2')
+        breakpoint2 = target.BreakpointCreateByLocation(source2, line2)
+        self.assertIsNotNone(breakpoint2)
+        self.assertTrue(breakpoint2.IsValid())
+
+        process = target.LaunchSimple(None, None, os.getcwd())
+        self.assertIsNotNone(process, PROCESS_IS_VALID)
+
+        threads = lldbutil.get_threads_stopped_at_breakpoint(
+            process, breakpoint2)
+        self.assertEqual(len(threads), 1)
+        frame = threads[0].GetFrameAtIndex(0)
+        value = frame.FindVariable("x")
+        self.assertTrue(value.IsValid())
+
+        process.Continue()
+
+        threads = lldbutil.get_threads_stopped_at_breakpoint(
+            process, breakpoint1)
+        self.assertEqual(len(threads), 1)
+        frame = threads[0].GetFrameAtIndex(0)
+        value = frame.FindVariable("x")
+        self.assertTrue(value.IsValid())
+
+        process.Continue()

lldb/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/decls.h

@@ -1,11 +1,11 @@
-struct struct1
-{
-    static void
-    f();
+struct struct1 {
+  ~struct1();
+  static void f();
 };
 
-struct struct2
-{
-    static void
-    f();
+struct struct2 {
+  ~struct2();
+  static void f();
 };
+
+int g();

lldb/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/file1.cpp

@@ -1,13 +1,21 @@
 #include "decls.h"
 
-void
-struct1::f()
-{
+int g() {
+  return 1;
 }
 
-int main()
-{
-    struct1::f();
-    struct2::f();
-    return 0;
+struct1::~struct1() {
+  int x = g(); // Break1
+}
+
+void struct1::f() {}
+
+int main() {
+  struct1::f();
+  struct2::f();
+
+  struct1 s1;
+  struct2 s2;
+
+  return 0;
 }

lldb/packages/Python/lldbsuite/test/python_api/symbol-context/two-files/file2.cpp

@@ -1,6 +1,7 @@
 #include "decls.h"
 
-void
-struct2::f()
-{
+struct2::~struct2() {
+  int x = g(); // Break2
 }
+
+void struct2::f() {}

lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.cpp

@@ -46,7 +46,7 @@ DWARFCompileUnit::DWARFCompileUnit(SymbolFileDWARF *dwarf2Data)
       m_producer_version_minor(0), m_producer_version_update(0),
       m_language_type(eLanguageTypeUnknown), m_is_dwarf64(false),
       m_is_optimized(eLazyBoolCalculate), m_addr_base(0),
-      m_base_obj_offset(DW_INVALID_OFFSET) {}
+      m_ranges_base(0), m_base_obj_offset(DW_INVALID_OFFSET) {}
 
 DWARFCompileUnit::~DWARFCompileUnit() {}
 
@@ -307,7 +307,9 @@ void DWARFCompileUnit::AddCompileUnitDIE(DWARFDebugInfoEntry &die) {
 
   dw_addr_t addr_base = cu_die.GetAttributeValueAsUnsigned(
       m_dwarf2Data, this, DW_AT_GNU_addr_base, 0);
-  dwo_cu->SetAddrBase(addr_base, m_offset);
+  dw_addr_t ranges_base = cu_die.GetAttributeValueAsUnsigned(
+      m_dwarf2Data, this, DW_AT_GNU_ranges_base, 0);
+  dwo_cu->SetAddrBase(addr_base, ranges_base, m_offset);
 }
 
 dw_offset_t DWARFCompileUnit::GetAbbrevOffset() const {
@@ -1114,8 +1116,10 @@ void DWARFCompileUnit::SetUserData(void *d) {
 }
 
 void DWARFCompileUnit::SetAddrBase(dw_addr_t addr_base,
+                                   dw_addr_t ranges_base,
                                    dw_offset_t base_obj_offset) {
   m_addr_base = addr_base;
+  m_ranges_base = ranges_base;
   m_base_obj_offset = base_obj_offset;
 }
 

lldb/source/Plugins/SymbolFile/DWARF/DWARFCompileUnit.h

@@ -70,7 +70,8 @@ public:
   uint8_t GetAddressByteSize() const { return m_addr_size; }
   dw_addr_t GetBaseAddress() const { return m_base_addr; }
   dw_addr_t GetAddrBase() const { return m_addr_base; }
-  void SetAddrBase(dw_addr_t addr_base, dw_offset_t base_obj_offset);
+  dw_addr_t GetRangesBase() const { return m_ranges_base; }
+  void SetAddrBase(dw_addr_t addr_base, dw_addr_t ranges_base, dw_offset_t base_obj_offset);
   void ClearDIEs(bool keep_compile_unit_die);
   void BuildAddressRangeTable(SymbolFileDWARF *dwarf2Data,
                               DWARFDebugAranges *debug_aranges);
@@ -185,10 +186,11 @@ protected:
   lldb::LanguageType m_language_type;
   bool m_is_dwarf64;
   lldb_private::LazyBool m_is_optimized;
-  dw_addr_t m_addr_base; // Value of DW_AT_addr_base
-  dw_offset_t
-      m_base_obj_offset; // If this is a dwo compile unit this is the offset of
-                         // the base compile unit in the main object file
+  dw_addr_t m_addr_base;         // Value of DW_AT_addr_base
+  dw_addr_t m_ranges_base;       // Value of DW_AT_ranges_base
+  dw_offset_t m_base_obj_offset; // If this is a dwo compile unit this is the
+                                 // offset of the base compile unit in the main
+                                 // object file
 
   void ParseProducerInfo();
 

lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugInfoEntry.cpp

@@ -450,7 +450,7 @@ bool DWARFDebugInfoEntry::GetDIENamesAndRanges(
         case DW_AT_ranges: {
           const DWARFDebugRanges *debug_ranges = dwarf2Data->DebugRanges();
           if (debug_ranges) {
-            debug_ranges->FindRanges(form_value.Unsigned(), ranges);
+            debug_ranges->FindRanges(cu->GetRangesBase(), form_value.Unsigned(), ranges);
             // All DW_AT_ranges are relative to the base address of the
             // compile unit. We add the compile unit base address to make
             // sure all the addresses are properly fixed up.
@@ -1108,7 +1108,7 @@ size_t DWARFDebugInfoEntry::GetAttributeAddressRanges(
   if (debug_ranges_offset != DW_INVALID_OFFSET) {
     DWARFDebugRanges *debug_ranges = dwarf2Data->DebugRanges();
 
-    debug_ranges->FindRanges(debug_ranges_offset, ranges);
+    debug_ranges->FindRanges(cu->GetRangesBase(), debug_ranges_offset, ranges);
     ranges.Slide(cu->GetBaseAddress());
   } else if (check_hi_lo_pc) {
     dw_addr_t lo_pc = LLDB_INVALID_ADDRESS;
@@ -1772,7 +1772,7 @@ bool DWARFDebugInfoEntry::LookupAddress(const dw_addr_t address,
         if (debug_ranges_offset != DW_INVALID_OFFSET) {
           DWARFRangeList ranges;
           DWARFDebugRanges *debug_ranges = dwarf2Data->DebugRanges();
-          debug_ranges->FindRanges(debug_ranges_offset, ranges);
+          debug_ranges->FindRanges(cu->GetRangesBase(), debug_ranges_offset, ranges);
           // All DW_AT_ranges are relative to the base address of the
           // compile unit. We add the compile unit base address to make
           // sure all the addresses are properly fixed up.

lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.cpp

@@ -118,9 +118,11 @@ void DWARFDebugRanges::Dump(Stream &s,
   }
 }
 
-bool DWARFDebugRanges::FindRanges(dw_offset_t debug_ranges_offset,
+bool DWARFDebugRanges::FindRanges(dw_addr_t debug_ranges_base,
+                                  dw_offset_t debug_ranges_offset,
                                   DWARFRangeList &range_list) const {
-  range_map_const_iterator pos = m_range_map.find(debug_ranges_offset);
+  dw_addr_t debug_ranges_address = debug_ranges_base + debug_ranges_offset;
+  range_map_const_iterator pos = m_range_map.find(debug_ranges_address);
   if (pos != m_range_map.end()) {
     range_list = pos->second;
     return true;

lldb/source/Plugins/SymbolFile/DWARF/DWARFDebugRanges.h

@@ -23,7 +23,8 @@ public:
   static void Dump(lldb_private::Stream &s,
                    const lldb_private::DWARFDataExtractor &debug_ranges_data,
                    lldb::offset_t *offset_ptr, dw_addr_t cu_base_addr);
-  bool FindRanges(dw_offset_t debug_ranges_offset,
+  bool FindRanges(dw_addr_t debug_ranges_base,
+                  dw_offset_t debug_ranges_offset,
                   DWARFRangeList &range_list) const;
 
 protected:

lldb/source/Plugins/SymbolFile/DWARF/SymbolFileDWARF.cpp

@@ -3810,7 +3810,8 @@ VariableSP SymbolFileDWARF::ParseVariableDIE(const SymbolContext &sc,
             if (form_value.Form() == DW_FORM_sec_offset) {
               DWARFRangeList dwarf_scope_ranges;
               const DWARFDebugRanges *debug_ranges = DebugRanges();
-              debug_ranges->FindRanges(form_value.Unsigned(),
+              debug_ranges->FindRanges(die.GetCU()->GetRangesBase(),
+                                       form_value.Unsigned(),
                                        dwarf_scope_ranges);
 
               // All DW_AT_start_scope are relative to the base address of the