Fix i386 relocations to Weak Definitions. The relocation entries should be

external and the item to be relocated should not have the address of the
symbol added in.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103302 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 113 insertions, 58 deletions

diff --git a/include/llvm/MC/MCMachOSymbolFlags.h b/include/llvm/MC/MCMachOSymbolFlags.h
new file mode 100644
index 0000000000..c938c81f69
--- /dev/null
+++ b/include/llvm/MC/MCMachOSymbolFlags.h
@@ -0,0 +1,44 @@
+//===- MCMachOSymbolFlags.h - MachO Symbol Flags ----------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the SymbolFlags used for the MachO target.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCMACHOSYMBOLFLAGS_H
+#define LLVM_MC_MCMACHOSYMBOLFLAGS_H
+
+// These flags are mostly used in MCMachOStreamer.cpp but also needed in
+// MachObjectWriter.cpp to test for Weak Definitions of symbols to emit
+// the correct relocation information.
+
+namespace llvm {
+  /// SymbolFlags - We store the value for the 'desc' symbol field in the lowest
+  /// 16 bits of the implementation defined flags.
+  enum SymbolFlags { // See <mach-o/nlist.h>.
+    SF_DescFlagsMask                        = 0xFFFF,
+
+    // Reference type flags.
+    SF_ReferenceTypeMask                    = 0x0007,
+    SF_ReferenceTypeUndefinedNonLazy        = 0x0000,
+    SF_ReferenceTypeUndefinedLazy           = 0x0001,
+    SF_ReferenceTypeDefined                 = 0x0002,
+    SF_ReferenceTypePrivateDefined          = 0x0003,
+    SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
+    SF_ReferenceTypePrivateUndefinedLazy    = 0x0005,
+
+    // Other 'desc' flags.
+    SF_NoDeadStrip                          = 0x0020,
+    SF_WeakReference                        = 0x0040,
+    SF_WeakDefinition                       = 0x0080
+  };
+
+} // end namespace llvm
+
+#endif
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 5ca31943f1..aa8b1ca1de 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -16,6 +16,7 @@
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCSection.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCMachOSymbolFlags.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Target/TargetAsmBackend.h"
@@ -25,25 +26,6 @@ using namespace llvm;
 namespace {
 
 class MCMachOStreamer : public MCStreamer {
-  /// SymbolFlags - We store the value for the 'desc' symbol field in the lowest
-  /// 16 bits of the implementation defined flags.
-  enum SymbolFlags { // See <mach-o/nlist.h>.
-    SF_DescFlagsMask                        = 0xFFFF,
-
-    // Reference type flags.
-    SF_ReferenceTypeMask                    = 0x0007,
-    SF_ReferenceTypeUndefinedNonLazy        = 0x0000,
-    SF_ReferenceTypeUndefinedLazy           = 0x0001,
-    SF_ReferenceTypeDefined                 = 0x0002,
-    SF_ReferenceTypePrivateDefined          = 0x0003,
-    SF_ReferenceTypePrivateUndefinedNonLazy = 0x0004,
-    SF_ReferenceTypePrivateUndefinedLazy    = 0x0005,
-
-    // Other 'desc' flags.
-    SF_NoDeadStrip                          = 0x0020,
-    SF_WeakReference                        = 0x0040,
-    SF_WeakDefinition                       = 0x0080
-  };
 
 private:
   MCAssembler Assembler;
diff --git a/lib/MC/MachObjectWriter.cpp b/lib/MC/MachObjectWriter.cpp
index bb8eb10a48..0dbb2c1c0e 100644
--- a/lib/MC/MachObjectWriter.cpp
+++ b/lib/MC/MachObjectWriter.cpp
@@ -16,6 +16,7 @@
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSectionMachO.h"
 #include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCMachOSymbolFlags.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/MachO.h"
@@ -753,9 +754,19 @@ public:
       const MCSymbol *Symbol = &Target.getSymA()->getSymbol();
       MCSymbolData *SD = &Asm.getSymbolData(*Symbol);
 
-      if (Symbol->isUndefined()) {
+      // Both references to undefined symbols and references to Weak Definitions
+      // get external relocation entries.  This is so the static and then the
+      // the dynamic linker can resolve them to the actual definition that will
+      // be used.  And in the case of Weak Definitions a reference to one will
+      // not always be to the definition in the same object file.
+      if (Symbol->isUndefined() || (SD->getFlags() & SF_WeakDefinition)) {
         IsExtern = 1;
         Index = SD->getIndex();
+        // In the case of a Weak Definition the FixedValue needs to be set to
+        // to not have the address of the symbol.  In the case of an undefined
+        // symbol you can't call getSymbolAddress().
+        if (SD->getFlags() & SF_WeakDefinition)
+          FixedValue -= Layout.getSymbolAddress(SD);
         Value = 0;
       } else {
         // The index is the section ordinal (1-based).
diff --git a/test/MC/MachO/reloc.s b/test/MC/MachO/reloc.s
index 73a69c3cc5..d935fea5d2 100644
--- a/test/MC/MachO/reloc.s
+++ b/test/MC/MachO/reloc.s
@@ -44,6 +44,13 @@ L1:
         .objc_class_name_A=0
 	.globl .objc_class_name_A
 
+        .text
+        .globl _f1
+        .weak_definition _f1
+_f1:
+        .data
+        .long _f1
+
 // CHECK: ('cputype', 7)
 // CHECK: ('cpusubtype', 3)
 // CHECK: ('filetype', 1)
@@ -56,9 +63,9 @@ L1:
 // CHECK:   ('size', 260)
 // 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', 63)
+// CHECK:   ('vm_size', 67)
 // CHECK:   ('file_offset', 392)
-// CHECK:   ('file_size', 63)
+// CHECK:   ('file_size', 67)
 // CHECK:   ('maxprot', 7)
 // CHECK:   ('initprot', 7)
 // CHECK:   ('num_sections', 3)
@@ -71,7 +78,7 @@ L1:
 // CHECK:     ('size', 8)
 // CHECK:     ('offset', 392)
 // CHECK:     ('alignment', 0)
-// CHECK:     ('reloc_offset', 456)
+// CHECK:     ('reloc_offset', 460)
 // CHECK:     ('num_reloc', 1)
 // CHECK:     ('flags', 0x80000400)
 // CHECK:     ('reserved1', 0)
@@ -82,58 +89,61 @@ L1:
 // CHECK:     (('word-0', 0x1),
 // CHECK:      ('word-1', 0x5000003)),
 // CHECK:   ])
-// CHECK:   ('_section_data', '\xe92\x00\x00\x00\xeb\xf9\xc3')
+// CHECK:   ('_section_data', '\xe96\x00\x00\x00\xeb\xf9\xc3')
 // CHECK:     # Section 1
 // CHECK:    (('section_name', '__data\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:     ('segment_name', '__DATA\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:     ('address', 8)
-// CHECK:     ('size', 43)
+// CHECK:     ('size', 47)
 // CHECK:     ('offset', 400)
 // CHECK:     ('alignment', 0)
-// CHECK:     ('reloc_offset', 464)
-// CHECK:     ('num_reloc', 9)
+// CHECK:     ('reloc_offset', 468)
+// CHECK:     ('num_reloc', 10)
 // CHECK:     ('flags', 0x0)
 // CHECK:     ('reserved1', 0)
 // CHECK:     ('reserved2', 0)
 // CHECK:    ),
 // CHECK:   ('_relocations', [
 // CHECK:     # Relocation 0
+// CHECK:     (('word-0', 0x2b),
+// CHECK:      ('word-1', 0xc000007)),
+// CHECK:     # Relocation 1
 // CHECK:     (('word-0', 0x8000002a),
 // CHECK:      ('word-1', 0x18)),
-// CHECK:     # Relocation 1
+// CHECK:     # Relocation 2
 // CHECK:     (('word-0', 0x90000028),
 // CHECK:      ('word-1', 0x18)),
-// CHECK:     # Relocation 2
+// CHECK:     # Relocation 3
 // CHECK:     (('word-0', 0xa0000024),
 // CHECK:      ('word-1', 0x18)),
-// CHECK:     # Relocation 3
+// CHECK:     # Relocation 4
 // CHECK:     (('word-0', 0xa0000020),
 // CHECK:      ('word-1', 0x18)),
-// CHECK:     # Relocation 4
+// CHECK:     # Relocation 5
 // CHECK:     (('word-0', 0xa4000014),
 // CHECK:      ('word-1', 0x1c)),
-// CHECK:     # Relocation 5
+// CHECK:     # Relocation 6
 // CHECK:     (('word-0', 0xa1000000),
 // CHECK:      ('word-1', 0x24)),
-// CHECK:     # Relocation 6
+// CHECK:     # Relocation 7
 // CHECK:     (('word-0', 0x8),
 // CHECK:      ('word-1', 0x4000002)),
-// CHECK:     # Relocation 7
-// CHECK:     (('word-0', 0x4),
-// CHECK:      ('word-1', 0xc000008)),
 // CHECK:     # Relocation 8
+// CHECK:     (('word-0', 0x4),
+// CHECK:      ('word-1', 0xc000009)),
+// CHECK:     # Relocation 9
 // CHECK:     (('word-0', 0x0),
-// CHECK:      ('word-1', 0xc000008)),
+// CHECK:      ('word-1', 0xc000009)),
 // CHECK:   ])
-// CHECK:   ('_section_data', '\x00\x00\x00\x00\x04\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xed\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x19\x00\x00\x00"\x00\x00\x00,\x00q')
+// CHECK:   ('_section_data', '\x00\x00\x00\x00\x04\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\xed\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x19\x00\x00\x00"\x00\x00\x00,\x00q\x00\x00\x00\x00')
 // CHECK:     # Section 2
 // CHECK:    (('section_name', '__const\x00\x00\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:     ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
-// CHECK:     ('address', 51)
+// CHECK:     ('address', 55)
 // CHECK:     ('size', 12)
-// CHECK:     ('offset', 443)
+// CHECK:     ('offset', 447)
 // CHECK:     ('alignment', 0)
-// CHECK:     ('reloc_offset', 536)
+// CHECK:     ('reloc_offset', 548)
 // CHECK:     ('num_reloc', 4)
 // CHECK:     ('flags', 0x0)
 // CHECK:     ('reserved1', 0)
@@ -151,22 +161,22 @@ L1:
 // CHECK:      ('word-1', 0x18)),
 // CHECK:     # Relocation 3
 // CHECK:     (('word-0', 0xa1000000),
-// CHECK:      ('word-1', 0x33)),
+// CHECK:      ('word-1', 0x37)),
 // CHECK:   ])
-// CHECK:   ('_section_data', '\x06\x00\x00\x007\x00\x00\x00\x00\x00\x00\x00')
+// CHECK:   ('_section_data', '\x02\x00\x00\x00;\x00\x00\x00\x00\x00\x00\x00')
 // CHECK:   ])
 // CHECK:  ),
 // CHECK:   # Load Command 1
 // CHECK:  (('command', 2)
 // CHECK:   ('size', 24)
-// CHECK:   ('symoff', 568)
-// CHECK:   ('nsyms', 9)
-// CHECK:   ('stroff', 676)
-// CHECK:   ('strsize', 84)
-// CHECK:   ('_string_data', '\x00undef\x00local_a_ext\x00.objc_class_name_A\x00local_a\x00local_a_elt\x00local_b\x00local_c\x00bar\x00_f0\x00\x00\x00')
+// CHECK:   ('symoff', 580)
+// CHECK:   ('nsyms', 10)
+// CHECK:   ('stroff', 700)
+// CHECK:   ('strsize', 88)
+// CHECK:   ('_string_data', '\x00undef\x00local_a_ext\x00.objc_class_name_A\x00_f1\x00local_a\x00local_a_elt\x00local_b\x00local_c\x00bar\x00_f0\x00\x00\x00')
 // CHECK:   ('_symbols', [
 // CHECK:     # Symbol 0
-// CHECK:    (('n_strx', 38)
+// CHECK:    (('n_strx', 42)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 2)
 // CHECK:     ('n_desc', 0)
@@ -174,7 +184,7 @@ L1:
 // CHECK:     ('_string', 'local_a')
 // CHECK:    ),
 // CHECK:     # Symbol 1
-// CHECK:    (('n_strx', 46)
+// CHECK:    (('n_strx', 50)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 2)
 // CHECK:     ('n_desc', 0)
@@ -182,7 +192,7 @@ L1:
 // CHECK:     ('_string', 'local_a_elt')
 // CHECK:    ),
 // CHECK:     # Symbol 2
-// CHECK:    (('n_strx', 58)
+// CHECK:    (('n_strx', 62)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 2)
 // CHECK:     ('n_desc', 0)
@@ -190,7 +200,7 @@ L1:
 // CHECK:     ('_string', 'local_b')
 // CHECK:    ),
 // CHECK:     # Symbol 3
-// CHECK:    (('n_strx', 66)
+// CHECK:    (('n_strx', 70)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 2)
 // CHECK:     ('n_desc', 0)
@@ -198,15 +208,15 @@ L1:
 // CHECK:     ('_string', 'local_c')
 // CHECK:    ),
 // CHECK:     # Symbol 4
-// CHECK:    (('n_strx', 74)
+// CHECK:    (('n_strx', 78)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 3)
 // CHECK:     ('n_desc', 0)
-// CHECK:     ('n_value', 51)
+// CHECK:     ('n_value', 55)
 // CHECK:     ('_string', 'bar')
 // CHECK:    ),
 // CHECK:     # Symbol 5
-// CHECK:    (('n_strx', 78)
+// CHECK:    (('n_strx', 82)
 // CHECK:     ('n_type', 0xe)
 // CHECK:     ('n_sect', 1)
 // CHECK:     ('n_desc', 0)
@@ -222,6 +232,14 @@ L1:
 // CHECK:     ('_string', '.objc_class_name_A')
 // CHECK:    ),
 // CHECK:     # Symbol 7
+// CHECK:    (('n_strx', 38)
+// CHECK:     ('n_type', 0xf)
+// CHECK:     ('n_sect', 1)
+// CHECK:     ('n_desc', 128)
+// CHECK:     ('n_value', 8)
+// CHECK:     ('_string', '_f1')
+// CHECK:    ),
+// CHECK:     # Symbol 8
 // CHECK:    (('n_strx', 7)
 // CHECK:     ('n_type', 0xf)
 // CHECK:     ('n_sect', 2)
@@ -229,7 +247,7 @@ L1:
 // CHECK:     ('n_value', 16)
 // CHECK:     ('_string', 'local_a_ext')
 // CHECK:    ),
-// CHECK:     # Symbol 8
+// CHECK:     # Symbol 9
 // CHECK:    (('n_strx', 1)
 // CHECK:     ('n_type', 0x1)
 // CHECK:     ('n_sect', 0)
@@ -245,8 +263,8 @@ L1:
 // CHECK:   ('ilocalsym', 0)
 // CHECK:   ('nlocalsym', 6)
 // CHECK:   ('iextdefsym', 6)
-// CHECK:   ('nextdefsym', 2)
-// CHECK:   ('iundefsym', 8)
+// CHECK:   ('nextdefsym', 3)
+// CHECK:   ('iundefsym', 9)
 // CHECK:   ('nundefsym', 1)
 // CHECK:   ('tocoff', 0)
 // CHECK:   ('ntoc', 0)