MC/Mach-O/x86_64: Relocations in debug sections should use local relocations

when possible.
 - <rdar://problem/7934873>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103092 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 70 insertions, 21 deletions

diff --git a/include/llvm/MC/MCSectionMachO.h b/include/llvm/MC/MCSectionMachO.h
index f3bc8ed..2e634b0 100644
--- a/include/llvm/MC/MCSectionMachO.h
+++ b/include/llvm/MC/MCSectionMachO.h
@@ -136,6 +136,9 @@ public:
   unsigned getStubSize() const { return Reserved2; }
 
   unsigned getType() const { return TypeAndAttributes & SECTION_TYPE; }
+  bool hasAttribute(unsigned Value) const {
+    return (TypeAndAttributes & Value) != 0;
+  }
 
   /// ParseSectionSpecifier - Parse the section specifier indicated by "Spec".
   /// This is a string that can appear after a .section directive in a mach-o
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index a533ccf..f4aef96 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -548,6 +548,17 @@ public:
       MCSymbolData &SD = Asm.getSymbolData(*Symbol);
       const MCSymbolData *Base = Asm.getAtom(Layout, &SD);
 
+      // Relocations inside debug sections always use local relocations when
+      // possible. This seems to be done because the debugger doesn't fully
+      // understand x86_64 relocation entries, and expects to find values that
+      // have already been fixed up.
+      if (Symbol->isDefined()) {
+        const MCSectionMachO &Section = static_cast<const MCSectionMachO&>(
+          Fragment->getParent()->getSection());
+        if (Section.hasAttribute(MCSectionMachO::S_ATTR_DEBUG))
+          Base = 0;
+      }
+
       // x86_64 almost always uses external relocations, except when there is no
       // symbol to use as a base address (a local symbol with no preceeding
       // non-local symbol).
diff --git a/test/MC/MachO/darwin-x86_64-reloc.s b/test/MC/MachO/darwin-x86_64-reloc.s
index d5e75d1..eefe298 100644
--- a/test/MC/MachO/darwin-x86_64-reloc.s
+++ b/test/MC/MachO/darwin-x86_64-reloc.s
@@ -42,25 +42,29 @@ L1:
 .long	_foobar@GOTPCREL+4
 .long	_foo@GOTPCREL+4
 
+        .section	__DWARF,__debug_frame,regular,debug
+        .quad L1
+        .quad _ext_foo
+
 // CHECK: ('cputype', 16777223)
 // CHECK: ('cpusubtype', 3)
 // CHECK: ('filetype', 1)
 // CHECK: ('num_load_commands', 1)
-// CHECK: ('load_commands_size', 336)
+// CHECK: ('load_commands_size', 416)
 // CHECK: ('flag', 0)
 // CHECK: ('reserved', 0)
 // CHECK: ('load_commands', [
 // CHECK:   # Load Command 0
 // CHECK:  (('command', 25)
-// CHECK:   ('size', 232)
+// CHECK:   ('size', 312)
 // CHECK:   ('segment_name', '\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:   ('vm_addr', 0)
-// CHECK:   ('vm_size', 189)
-// CHECK:   ('file_offset', 368)
-// CHECK:   ('file_size', 189)
+// CHECK:   ('vm_size', 205)
+// CHECK:   ('file_offset', 448)
+// CHECK:   ('file_size', 205)
 // CHECK:   ('maxprot', 7)
 // CHECK:   ('initprot', 7)
-// CHECK:   ('num_sections', 2)
+// CHECK:   ('num_sections', 3)
 // CHECK:   ('flags', 0)
 // CHECK:   ('sections', [
 // CHECK:     # Section 0
@@ -68,9 +72,9 @@ L1:
 // CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:     ('address', 0)
 // CHECK:     ('size', 181)
-// CHECK:     ('offset', 368)
+// CHECK:     ('offset', 448)
 // CHECK:     ('alignment', 0)
-// CHECK:     ('reloc_offset', 560)
+// CHECK:     ('reloc_offset', 656)
 // CHECK:     ('num_reloc', 27)
 // CHECK:     ('flags', 0x80000400)
 // CHECK:     ('reserved1', 0)
@@ -166,9 +170,9 @@ L1:
 // CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:     ('address', 181)
 // CHECK:     ('size', 8)
-// CHECK:     ('offset', 549)
+// CHECK:     ('offset', 629)
 // CHECK:     ('alignment', 0)
-// CHECK:     ('reloc_offset', 776)
+// CHECK:     ('reloc_offset', 872)
 // CHECK:     ('num_reloc', 2)
 // CHECK:     ('flags', 0x0)
 // CHECK:     ('reserved1', 0)
@@ -181,22 +185,45 @@ L1:
 // CHECK:      ('word-1', 0x4d000000)),
 // CHECK:     # Relocation 1
 // CHECK:     (('word-0', 0x0),
-// CHECK:      ('word-1', 0x4d000004)),
+// CHECK:      ('word-1', 0x4d000005)),
 // CHECK:   ])
 // CHECK:   ('_section_data', '\x04\x00\x00\x00\x04\x00\x00\x00')
+// CHECK:     # Section 2
+// CHECK:    (('section_name', '__debug_frame\x00\x00\x00')
+// CHECK:     ('segment_name', '__DWARF\x00\x00\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:     ('address', 189)
+// CHECK:     ('size', 16)
+// CHECK:     ('offset', 637)
+// CHECK:     ('alignment', 0)
+// CHECK:     ('reloc_offset', 888)
+// CHECK:     ('num_reloc', 2)
+// CHECK:     ('flags', 0x2000000)
+// CHECK:     ('reserved1', 0)
+// CHECK:     ('reserved2', 0)
+// CHECK:     ('reserved3', 0)
+// CHECK:    ),
+// CHECK:   ('_relocations', [
+// CHECK:     # Relocation 0
+// CHECK:     (('word-0', 0x8),
+// CHECK:      ('word-1', 0xe000004)),
+// CHECK:     # Relocation 1
+// CHECK:     (('word-0', 0x0),
+// CHECK:      ('word-1', 0x6000001)),
+// CHECK:   ])
+// CHECK:   ('_section_data', '\xad\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:   ])
 // CHECK:  ),
 // CHECK:   # Load Command 1
 // CHECK:  (('command', 2)
 // CHECK:   ('size', 24)
-// CHECK:   ('symoff', 792)
-// CHECK:   ('nsyms', 5)
-// CHECK:   ('stroff', 872)
-// CHECK:   ('strsize', 32)
-// CHECK:   ('_string_data', '\x00_foobar\x00_foo\x00_baz\x00_bar\x00_prev\x00\x00\x00')
+// CHECK:   ('symoff', 904)
+// CHECK:   ('nsyms', 6)
+// CHECK:   ('stroff', 1000)
+// CHECK:   ('strsize', 40)
+// CHECK:   ('_string_data', '\x00_foobar\x00_ext_foo\x00_foo\x00_baz\x00_bar\x00_prev\x00\x00')
 // CHECK:   ('_symbols', [
 // CHECK:     # Symbol 0
-// CHECK:    (('n_strx', 9)
+// CHECK:    (('n_strx', 18)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 1)
 // CHECK:     ('n_desc', 0)
@@ -204,7 +231,7 @@ L1:
 // CHECK:     ('_string', '_foo')
 // CHECK:    ),
 // CHECK:     # Symbol 1
-// CHECK:    (('n_strx', 14)
+// CHECK:    (('n_strx', 23)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 1)
 // CHECK:     ('n_desc', 0)
@@ -212,7 +239,7 @@ L1:
 // CHECK:     ('_string', '_baz')
 // CHECK:    ),
 // CHECK:     # Symbol 2
-// CHECK:    (('n_strx', 19)
+// CHECK:    (('n_strx', 28)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 1)
 // CHECK:     ('n_desc', 0)
@@ -220,7 +247,7 @@ L1:
 // CHECK:     ('_string', '_bar')
 // CHECK:    ),
 // CHECK:     # Symbol 3
-// CHECK:    (('n_strx', 24)
+// CHECK:    (('n_strx', 33)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 1)
 // CHECK:     ('n_desc', 0)
@@ -228,6 +255,14 @@ L1:
 // CHECK:     ('_string', '_prev')
 // CHECK:    ),
 // CHECK:     # Symbol 4
+// CHECK:    (('n_strx', 9)
+// CHECK:     ('n_type', 0x1)
+// CHECK:     ('n_sect', 0)
+// CHECK:     ('n_desc', 0)
+// CHECK:     ('n_value', 0)
+// CHECK:     ('_string', '_ext_foo')
+// CHECK:    ),
+// CHECK:     # Symbol 5
 // CHECK:    (('n_strx', 1)
 // CHECK:     ('n_type', 0x1)
 // CHECK:     ('n_sect', 0)
@@ -245,7 +280,7 @@ L1:
 // CHECK:   ('iextdefsym', 4)
 // CHECK:   ('nextdefsym', 0)
 // CHECK:   ('iundefsym', 4)
-// CHECK:   ('nundefsym', 1)
+// CHECK:   ('nundefsym', 2)
 // CHECK:   ('tocoff', 0)
 // CHECK:   ('ntoc', 0)
 // CHECK:   ('modtaboff', 0)