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MC/Mach-O/x86_64: Darwin's special "signed_N" relocation types should only be

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used to replace a normal relocation, not a reference to a GOT entry.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103789 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Dunbar 2010-05-14 18:53:40 +00:00
parent 4ed1082683
commit f0f6cdb6b4
2 changed files with 80 additions and 74 deletions
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46
lib/MC/MachObjectWriter.cpp
View File

@ -609,10 +609,31 @@ public:
Type = RIT_X86_64_GOTLoad;
else
Type = RIT_X86_64_GOT;
} else if (Modifier != MCSymbolRefExpr::VK_None)
} else if (Modifier != MCSymbolRefExpr::VK_None) {
report_fatal_error("unsupported symbol modifier in relocation");
else
} else {
Type = RIT_X86_64_Signed;
// The Darwin x86_64 relocation format has a problem where it cannot
// encode an address (L<foo> + <constant>) which is outside the atom
// containing L<foo>. Generally, this shouldn't occur but it does
// happen when we have a RIPrel instruction with data following the
// relocation entry (e.g., movb $012, L0(%rip)). Even with the PCrel
// adjustment Darwin x86_64 uses, the offset is still negative and
// the linker has no way to recognize this.
//
// To work around this, Darwin uses several special relocation types
// to indicate the offsets. However, the specification or
// implementation of these seems to also be incomplete; they should
// adjust the addend as well based on the actual encoded instruction
// (the additional bias), but instead appear to just look at the
// final offset.
switch (-(Target.getConstant() + (1LL << Log2Size))) {
case 1: Type = RIT_X86_64_Signed1; break;
case 2: Type = RIT_X86_64_Signed2; break;
case 4: Type = RIT_X86_64_Signed4; break;
}
}
} else {
if (Modifier != MCSymbolRefExpr::VK_None)
report_fatal_error("unsupported symbol modifier in branch "
@ -620,27 +641,6 @@ public:
Type = RIT_X86_64_Branch;
}
// The Darwin x86_64 relocation format has a problem where it cannot
// encode an address (L<foo> + <constant>) which is outside the atom
// containing L<foo>. Generally, this shouldn't occur but it does happen
// when we have a RIPrel instruction with data following the relocation
// entry (e.g., movb $012, L0(%rip)). Even with the PCrel adjustment
// Darwin x86_64 uses, the offset is still negative and the linker has
// no way to recognize this.
//
// To work around this, Darwin uses several special relocation types to
// indicate the offsets. However, the specification or implementation of
// these seems to also be incomplete; they should adjust the addend as
// well based on the actual encoded instruction (the additional bias),
// but instead appear to just look at the final offset.
if (IsRIPRel) {
switch (-(Target.getConstant() + (1LL << Log2Size))) {
case 1: Type = RIT_X86_64_Signed1; break;
case 2: Type = RIT_X86_64_Signed2; break;
case 4: Type = RIT_X86_64_Signed4; break;
}
}
} else {
if (Modifier == MCSymbolRefExpr::VK_GOT) {
Type = RIT_X86_64_GOT;

108
test/MC/MachO/darwin-x86_64-reloc.s
View File

@ -84,6 +84,9 @@ L6:
.quad f6
.quad L6
.text
cmpq $0, _foo@GOTPCREL(%rip)
// CHECK: ('cputype', 16777223)
// CHECK: ('cpusubtype', 3)
// CHECK: ('filetype', 1)
@ -97,9 +100,9 @@ L6:
// CHECK: ('size', 392)
// 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', 303)
// CHECK: ('vm_size', 311)
// CHECK: ('file_offset', 528)
// CHECK: ('file_size', 303)
// CHECK: ('file_size', 311)
// CHECK: ('maxprot', 7)
// CHECK: ('initprot', 7)
// CHECK: ('num_sections', 4)
@ -112,7 +115,7 @@ L6:
// CHECK: ('size', 40)
// CHECK: ('offset', 528)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 832)
// CHECK: ('reloc_offset', 840)
// CHECK: ('num_reloc', 5)
// CHECK: ('flags', 0x0)
// CHECK: ('reserved1', 0)
@ -136,16 +139,16 @@ L6:
// CHECK: (('word-0', 0x4),
// CHECK: ('word-1', 0x4d000008)),
// CHECK: ])
// CHECK: ('_section_data', "\x00\x00\x00\x00\x04\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x17\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'\x01\x00\x00\x00\x00\x00\x00")
// CHECK: ('_section_data', '\x00\x00\x00\x00\x04\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x1f\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00/\x01\x00\x00\x00\x00\x00\x00')
// CHECK: # Section 1
// CHECK: (('section_name', '__text\x00\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', 40)
// CHECK: ('size', 215)
// CHECK: ('size', 223)
// CHECK: ('offset', 568)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 872)
// CHECK: ('num_reloc', 31)
// CHECK: ('reloc_offset', 880)
// CHECK: ('num_reloc', 32)
// CHECK: ('flags', 0x80000400)
// CHECK: ('reserved1', 0)
// CHECK: ('reserved2', 0)
@ -153,108 +156,111 @@ L6:
// CHECK: ),
// CHECK: ('_relocations', [
// CHECK: # Relocation 0
// CHECK: (('word-0', 0xda),
// CHECK: ('word-1', 0x4d000000)),
// CHECK: # Relocation 1
// CHECK: (('word-0', 0xd3),
// CHECK: ('word-1', 0x15000004)),
// CHECK: # Relocation 1
// CHECK: # Relocation 2
// CHECK: (('word-0', 0xcd),
// CHECK: ('word-1', 0x1d000006)),
// CHECK: # Relocation 2
// CHECK: # Relocation 3
// CHECK: (('word-0', 0xc7),
// CHECK: ('word-1', 0x15000004)),
// CHECK: # Relocation 3
// CHECK: # Relocation 4
// CHECK: (('word-0', 0xc1),
// CHECK: ('word-1', 0x15000001)),
// CHECK: # Relocation 4
// CHECK: (('word-0', 0xa5),
// CHECK: ('word-1', 0x5e000003)),
// CHECK: # Relocation 5
// CHECK: (('word-0', 0xa5),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 6
// CHECK: (('word-0', 0x9d),
// CHECK: ('word-1', 0x5e000003)),
// CHECK: # Relocation 6
// CHECK: (('word-0', 0xa5),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 7
// CHECK: (('word-0', 0x9d),
// CHECK: ('word-1', 0xe000000)),
// CHECK: ('word-1', 0x5e000003)),
// CHECK: # Relocation 8
// CHECK: (('word-0', 0x9d),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 9
// CHECK: (('word-0', 0x95),
// CHECK: ('word-1', 0xe000003)),
// CHECK: # Relocation 9
// CHECK: # Relocation 10
// CHECK: (('word-0', 0x8d),
// CHECK: ('word-1', 0xe000003)),
// CHECK: # Relocation 10
// CHECK: # Relocation 11
// CHECK: (('word-0', 0x79),
// CHECK: ('word-1', 0x8d000003)),
// CHECK: # Relocation 11
// CHECK: # Relocation 12
// CHECK: (('word-0', 0x71),
// CHECK: ('word-1', 0x7d000003)),
// CHECK: # Relocation 12
// CHECK: # Relocation 13
// CHECK: (('word-0', 0x69),
// CHECK: ('word-1', 0x6d000003)),
// CHECK: # Relocation 13
// CHECK: # Relocation 14
// CHECK: (('word-0', 0x63),
// CHECK: ('word-1', 0x1d000003)),
// CHECK: # Relocation 14
// CHECK: # Relocation 15
// CHECK: (('word-0', 0x5c),
// CHECK: ('word-1', 0x1d000003)),
// CHECK: # Relocation 15
// CHECK: (('word-0', 0x55),
// CHECK: ('word-1', 0x5c000002)),
// CHECK: # Relocation 16
// CHECK: (('word-0', 0x55),
// CHECK: ('word-1', 0xc000000)),
// CHECK: ('word-1', 0x5c000002)),
// CHECK: # Relocation 17
// CHECK: (('word-0', 0x4d),
// CHECK: ('word-1', 0x5e000002)),
// CHECK: (('word-0', 0x55),
// CHECK: ('word-1', 0xc000000)),
// CHECK: # Relocation 18
// CHECK: (('word-0', 0x4d),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 19
// CHECK: (('word-0', 0x45),
// CHECK: ('word-1', 0x5e000002)),
// CHECK: # Relocation 19
// CHECK: (('word-0', 0x4d),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 20
// CHECK: (('word-0', 0x45),
// CHECK: ('word-1', 0xe000000)),
// CHECK: ('word-1', 0x5e000002)),
// CHECK: # Relocation 21
// CHECK: (('word-0', 0x3d),
// CHECK: (('word-0', 0x45),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 22
// CHECK: (('word-0', 0x35),
// CHECK: (('word-0', 0x3d),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 23
// CHECK: (('word-0', 0x35),
// CHECK: ('word-1', 0xe000000)),
// CHECK: # Relocation 24
// CHECK: (('word-0', 0x2d),
// CHECK: ('word-1', 0x8d000000)),
// CHECK: # Relocation 24
// CHECK: # Relocation 25
// CHECK: (('word-0', 0x26),
// CHECK: ('word-1', 0x6d000000)),
// CHECK: # Relocation 25
// CHECK: # Relocation 26
// CHECK: (('word-0', 0x20),
// CHECK: ('word-1', 0x1d000000)),
// CHECK: # Relocation 26
// CHECK: # Relocation 27
// CHECK: (('word-0', 0x1a),
// CHECK: ('word-1', 0x1d000000)),
// CHECK: # Relocation 27
// CHECK: # Relocation 28
// CHECK: (('word-0', 0x14),
// CHECK: ('word-1', 0x4d000000)),
// CHECK: # Relocation 28
// CHECK: # Relocation 29
// CHECK: (('word-0', 0xe),
// CHECK: ('word-1', 0x3d000000)),
// CHECK: # Relocation 29
// CHECK: # Relocation 30
// CHECK: (('word-0', 0x7),
// CHECK: ('word-1', 0x2d000000)),
// CHECK: # Relocation 30
// CHECK: # Relocation 31
// CHECK: (('word-0', 0x2),
// CHECK: ('word-1', 0x2d000000)),
// CHECK: ])
// CHECK: ('_section_data', '\xc3\xe8\x00\x00\x00\x00\xe8\x04\x00\x00\x00H\x8b\x05\x00\x00\x00\x00\xff5\x00\x00\x00\x00\x8b\x05\x00\x00\x00\x00\x8b\x05\x04\x00\x00\x00\xc6\x05\xff\xff\xff\xff\x12\xc7\x05\xfc\xff\xff\xffxV4\x12\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00H\x8d\x05,\x00\x00\x00H\x8d\x05\x14\x00\x00\x00\x83\x05\x13\x00\x00\x00\x06f\x81\x05\x12\x00\x00\x00\xf4\x01\x81\x05\x10\x00\x00\x00\xf4\x01\x00\x00\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90,\x00\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x00\x00\x00\x00\xe4\xff\xff\xff\xff\xff\xff\xff\xd4\xff\xff\xff\xff\xff\xff\xff,\x00\x00\x00\x00\x00\x00\x00\x83\xc0\x00\x03\x04%\x03\x00\x00\x00\x8b\x05\x1f\xff\xff\xff\x8b\x05$\x00\x00\x00\x8b\x05\x00\x00\x00\x00\x8b\x05(\x00\x00\x00')
// CHECK: ('_section_data', '\xc3\xe8\x00\x00\x00\x00\xe8\x04\x00\x00\x00H\x8b\x05\x00\x00\x00\x00\xff5\x00\x00\x00\x00\x8b\x05\x00\x00\x00\x00\x8b\x05\x04\x00\x00\x00\xc6\x05\xff\xff\xff\xff\x12\xc7\x05\xfc\xff\xff\xffxV4\x12\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00H\x8d\x05,\x00\x00\x00H\x8d\x05\x14\x00\x00\x00\x83\x05\x13\x00\x00\x00\x06f\x81\x05\x12\x00\x00\x00\xf4\x01\x81\x05\x10\x00\x00\x00\xf4\x01\x00\x00\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90\x90,\x00\x00\x00\x00\x00\x00\x00\x14\x00\x00\x00\x00\x00\x00\x00\xe4\xff\xff\xff\xff\xff\xff\xff\xd4\xff\xff\xff\xff\xff\xff\xff,\x00\x00\x00\x00\x00\x00\x00\x83\xc0\x00\x03\x04%\x03\x00\x00\x00\x8b\x05\x1f\xff\xff\xff\x8b\x05,\x00\x00\x00\x8b\x05\x00\x00\x00\x00\x8b\x050\x00\x00\x00H\x83=\xff\xff\xff\xff\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', 255)
// CHECK: ('address', 263)
// CHECK: ('size', 16)
// CHECK: ('offset', 783)
// CHECK: ('offset', 791)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 1120)
// CHECK: ('reloc_offset', 1136)
// CHECK: ('num_reloc', 2)
// CHECK: ('flags', 0x2000000)
// CHECK: ('reserved1', 0)
@ -273,9 +279,9 @@ L6:
// CHECK: # Section 3
// CHECK: (('section_name', '__literal8\x00\x00\x00\x00\x00\x00')
// CHECK: ('segment_name', '__TEXT\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00')
// CHECK: ('address', 271)
// CHECK: ('address', 279)
// CHECK: ('size', 32)
// CHECK: ('offset', 799)
// CHECK: ('offset', 807)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 0)
// CHECK: ('num_reloc', 0)
@ -292,9 +298,9 @@ L6:
// CHECK: # Load Command 1
// CHECK: (('command', 2)
// CHECK: ('size', 24)
// CHECK: ('symoff', 1136)
// CHECK: ('symoff', 1152)
// CHECK: ('nsyms', 9)
// CHECK: ('stroff', 1280)
// CHECK: ('stroff', 1296)
// CHECK: ('strsize', 52)
// CHECK: ('_string_data', '\x00_foobar\x00_ext_foo\x00_foo\x00_baz\x00_bar\x00_prev\x00_f2\x00_f3\x00f6\x00\x00\x00')
// CHECK: ('_symbols', [
@ -351,7 +357,7 @@ L6:
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 4)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 287)
// CHECK: ('n_value', 295)
// CHECK: ('_string', 'f6')
// CHECK: ),
// CHECK: # Symbol 7