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llvm-mc/Mach-O: Support symbol attributes.

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- This is mostly complete, the main thing missing is .indirect_symbol support
   (which would be straight-forward, except that the way it is implemented in
   'as' makes getting an exact .o match interesting).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79899 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Dunbar 2009-08-24 08:40:12 +00:00
parent 50e48b359e
commit 6aff2fbd56
4 changed files with 364 additions and 12 deletions
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28
include/llvm/MC/MCAssembler.h
View File

@ -317,6 +317,13 @@ public:
/// unit.
unsigned IsExternal : 1;
/// IsPrivateExtern - True if this symbol is private extern.
unsigned IsPrivateExtern : 1;
/// Flags - The Flags field is used by object file implementations to store
/// additional per symbol information which is not easily classified.
uint32_t Flags;
public:
// Only for use as sentinel.
MCSymbolData();
@ -334,13 +341,22 @@ public:
uint64_t getOffset() const { return Offset; }
void setOffset(uint64_t Value) { Offset = Value; }
/// @}
/// @name Symbol Attributes
/// @{
bool isExternal() const { return IsExternal; }
void setExternal(bool Value) { IsExternal = Value; }
/// @}
/// @name Symbol Attributes
/// @{
bool isExternal() const { return IsExternal; }
void setExternal(bool Value) { IsExternal = Value; }
bool isPrivateExtern() const { return IsPrivateExtern; }
void setPrivateExtern(bool Value) { IsPrivateExtern = Value; }
/// getFlags - Get the (implementation defined) symbol flags.
uint32_t getFlags() const { return Flags; }
/// setFlags - Set the (implementation defined) symbol flags.
void setFlags(uint32_t Value) { Flags = Value; }
/// @}
};

11
lib/MC/MCAssembler.cpp
View File

@ -291,7 +291,8 @@ public:
// FIXME: Set STAB bits.
// FIXME: Set private external bit.
if (MSD.SymbolData->isPrivateExtern())
Type |= STF_PrivateExtern;
// Set external bit.
if (MSD.SymbolData->isExternal() || Symbol.isUndefined())
@ -302,7 +303,11 @@ public:
Write32(MSD.StringIndex);
Write8(Type);
Write8(MSD.SectionIndex);
Write16(0); // FIXME: Desc
// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
// value.
Write16(MSD.SymbolData->getFlags() & 0xFFFF);
Write32(0); // FIXME: Value
}
@ -544,7 +549,7 @@ MCSymbolData::MCSymbolData() : Symbol(*(MCSymbol*)0) {}
MCSymbolData::MCSymbolData(MCSymbol &_Symbol, MCFragment *_Fragment,
uint64_t _Offset, MCAssembler *A)
: Symbol(_Symbol), Fragment(_Fragment), Offset(_Offset),
IsExternal(false)
IsExternal(false), IsPrivateExtern(false), Flags(0)
{
if (A)
A->getSymbolList().push_back(this);

83
lib/MC/MCMachOStreamer.cpp
View File

@ -19,6 +19,27 @@ 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;
MCSectionData *CurSectionData;
@ -121,6 +142,9 @@ void MCMachOStreamer::EmitLabel(MCSymbol *Symbol) {
assert(!SD.getFragment() && "Unexpected fragment on symbol data!");
SD.setFragment(F);
SD.setOffset(F->getContents().size());
// This causes the reference type and weak reference flags to be cleared.
SD.setFlags(SD.getFlags() & ~(SF_WeakReference | SF_ReferenceTypeMask));
Symbol->setSection(*CurSection);
}
@ -141,18 +165,71 @@ void MCMachOStreamer::EmitAssignment(MCSymbol *Symbol,
void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
SymbolAttr Attribute) {
// Adding a symbol attribute always introduces the symbol, note that an
// important side effect of calling getSymbolData here is to register the
// symbol with the assembler.
MCSymbolData &SD = getSymbolData(*Symbol);
// The implementation of symbol attributes is designed to match 'as', but it
// leaves much to desired. It doesn't really make sense to arbitrarily add and
// remove flags, but 'as' allows this (in particular, see .desc).
//
// In the future it might be worth trying to make these operations more well
// defined.
switch (Attribute) {
default:
llvm_unreachable("FIXME: Not yet implemented!");
case MCStreamer::Hidden:
case MCStreamer::Internal:
case MCStreamer::Protected:
case MCStreamer::Weak:
assert(0 && "Invalid symbol attribute for Mach-O!");
break;
case MCStreamer::Global:
getSymbolData(*Symbol).setExternal(true);
break;
case MCStreamer::LazyReference:
// FIXME: This requires -dynamic.
SD.setFlags(SD.getFlags() | SF_NoDeadStrip);
if (Symbol->isUndefined())
SD.setFlags(SD.getFlags() | SF_ReferenceTypeUndefinedLazy);
break;
case MCStreamer::IndirectSymbol:
llvm_unreachable("FIXME: Not yet implemented!");
break;
// Since .reference sets the no dead strip bit, it is equivalent to
// .no_dead_strip in practice.
case MCStreamer::Reference:
case MCStreamer::NoDeadStrip:
SD.setFlags(SD.getFlags() | SF_NoDeadStrip);
break;
case MCStreamer::PrivateExtern:
SD.setExternal(true);
SD.setPrivateExtern(true);
break;
case MCStreamer::WeakReference:
// FIXME: This requires -dynamic.
if (Symbol->isUndefined())
SD.setFlags(SD.getFlags() | SF_WeakReference);
break;
case MCStreamer::WeakDefinition:
// FIXME: 'as' enforces that this is defined and global. The manual claims
// it has to be in a coalesced section, but this isn't enforced.
SD.setFlags(SD.getFlags() | SF_WeakDefinition);
break;
}
}
void MCMachOStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
llvm_unreachable("FIXME: Not yet implemented!");
// Encode the 'desc' value into the lowest implementation defined bits.
assert(DescValue == (DescValue & SF_DescFlagsMask) &&
"Invalid .desc value!");
getSymbolData(*Symbol).setFlags(DescValue & SF_DescFlagsMask);
}
void MCMachOStreamer::EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value) {

254
test/MC/MachO/symbol-flags.s Normal file
View File

@ -0,0 +1,254 @@
// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump | FileCheck %s
.reference sym_ref_A
.reference sym_ref_def_A
sym_ref_def_A:
sym_ref_def_C:
.reference sym_ref_def_C
.weak_reference sym_weak_ref_A
.weak_reference sym_weak_ref_def_A
sym_weak_ref_def_A:
sym_weak_ref_def_B:
.weak_reference sym_weak_ref_def_B
.data
.globl sym_weak_def_A
.weak_definition sym_weak_def_A
sym_weak_def_A:
.lazy_reference sym_lazy_ref_A
.lazy_reference sym_lazy_ref_B
sym_lazy_ref_B:
sym_lazy_ref_C:
.lazy_reference sym_lazy_ref_C
.private_extern sym_private_ext_A
.private_extern sym_private_ext_B
sym_private_ext_B:
sym_private_ext_C:
.private_extern sym_private_ext_C
.private_extern sym_private_ext_D
.globl sym_private_ext_D
.no_dead_strip sym_no_dead_strip_A
.reference sym_ref_A
.desc sym_ref_A, 1
.desc sym_ref_A, 0x1234
.desc sym_desc_flags,0x47
sym_desc_flags:
// CHECK: ('cputype', 7)
// CHECK: ('cpusubtype', 3)
// CHECK: ('filetype', 1)
// CHECK: ('num_load_commands', 1)
// CHECK: ('load_commands_size', 296)
// CHECK: ('flag', 0)
// CHECK: ('load_commands', [
// CHECK: # Load Command 0
// CHECK: (('command', 1)
// CHECK: ('size', 192)
// 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', 0)
// CHECK: ('file_offset', 324)
// CHECK: ('file_size', 0)
// CHECK: ('maxprot', 7)
// CHECK: ('initprot', 7)
// CHECK: ('num_sections', 2)
// CHECK: ('flags', 0)
// CHECK: ('sections', [
// CHECK: # Section 0
// 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', 0)
// CHECK: ('size', 0)
// CHECK: ('offset', 324)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 0)
// CHECK: ('num_reloc', 0)
// CHECK: ('flags', 0x80000000)
// CHECK: ('reserved1', 0)
// CHECK: ('reserved2', 0)
// CHECK: ),
// 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', 0)
// CHECK: ('size', 0)
// CHECK: ('offset', 324)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 0)
// CHECK: ('num_reloc', 0)
// CHECK: ('flags', 0x0)
// CHECK: ('reserved1', 0)
// CHECK: ('reserved2', 0)
// CHECK: ),
// CHECK: ])
// CHECK: ),
// CHECK: # Load Command 1
// CHECK: (('command', 2)
// CHECK: ('size', 24)
// CHECK: ('symoff', 324)
// CHECK: ('nsyms', 16)
// CHECK: ('stroff', 516)
// CHECK: ('strsize', 260)
// CHECK: ('_string_data', '\x00sym_ref_A\x00sym_weak_ref_A\x00sym_weak_def_A\x00sym_lazy_ref_A\x00sym_private_ext_A\x00sym_private_ext_B\x00sym_private_ext_C\x00sym_private_ext_D\x00sym_no_dead_strip_A\x00sym_ref_def_A\x00sym_ref_def_C\x00sym_weak_ref_def_A\x00sym_weak_ref_def_B\x00sym_lazy_ref_B\x00sym_lazy_ref_C\x00sym_desc_flags\x00\x00')
// CHECK: ('_symbols', [
// CHECK: # Symbol 0
// CHECK: (('n_strx', 148)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 1)
// CHECK: ('n_desc', 32)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_ref_def_A')
// CHECK: ),
// CHECK: # Symbol 1
// CHECK: (('n_strx', 162)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 1)
// CHECK: ('n_desc', 32)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_ref_def_C')
// CHECK: ),
// CHECK: # Symbol 2
// CHECK: (('n_strx', 176)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 1)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_weak_ref_def_A')
// CHECK: ),
// CHECK: # Symbol 3
// CHECK: (('n_strx', 195)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 1)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_weak_ref_def_B')
// CHECK: ),
// CHECK: # Symbol 4
// CHECK: (('n_strx', 214)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 32)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_lazy_ref_B')
// CHECK: ),
// CHECK: # Symbol 5
// CHECK: (('n_strx', 229)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 32)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_lazy_ref_C')
// CHECK: ),
// CHECK: # Symbol 6
// CHECK: (('n_strx', 244)
// CHECK: ('n_type', 0xe)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_desc_flags')
// CHECK: ),
// CHECK: # Symbol 7
// CHECK: (('n_strx', 74)
// CHECK: ('n_type', 0x1f)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_private_ext_B')
// CHECK: ),
// CHECK: # Symbol 8
// CHECK: (('n_strx', 92)
// CHECK: ('n_type', 0x1f)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_private_ext_C')
// CHECK: ),
// CHECK: # Symbol 9
// CHECK: (('n_strx', 26)
// CHECK: ('n_type', 0xf)
// CHECK: ('n_sect', 2)
// CHECK: ('n_desc', 128)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_weak_def_A')
// CHECK: ),
// CHECK: # Symbol 10
// CHECK: (('n_strx', 41)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 33)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_lazy_ref_A')
// CHECK: ),
// CHECK: # Symbol 11
// CHECK: (('n_strx', 128)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 32)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_no_dead_strip_A')
// CHECK: ),
// CHECK: # Symbol 12
// CHECK: (('n_strx', 56)
// CHECK: ('n_type', 0x11)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_private_ext_A')
// CHECK: ),
// CHECK: # Symbol 13
// CHECK: (('n_strx', 110)
// CHECK: ('n_type', 0x11)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_private_ext_D')
// CHECK: ),
// CHECK: # Symbol 14
// CHECK: (('n_strx', 1)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 4660)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_ref_A')
// CHECK: ),
// CHECK: # Symbol 15
// CHECK: (('n_strx', 11)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 64)
// CHECK: ('n_value', 0)
// CHECK: ('_string', 'sym_weak_ref_A')
// CHECK: ),
// CHECK: ])
// CHECK: ),
// CHECK: # Load Command 2
// CHECK: (('command', 11)
// CHECK: ('size', 80)
// CHECK: ('ilocalsym', 0)
// CHECK: ('nlocalsym', 7)
// CHECK: ('iextdefsym', 7)
// CHECK: ('nextdefsym', 3)
// CHECK: ('iundefsym', 10)
// CHECK: ('nundefsym', 6)
// CHECK: ('tocoff', 0)
// CHECK: ('ntoc', 0)
// CHECK: ('modtaboff', 0)
// CHECK: ('nmodtab', 0)
// CHECK: ('extrefsymoff', 0)
// CHECK: ('nextrefsyms', 0)
// CHECK: ('indirectsymoff', 0)
// CHECK: ('nindirectsyms', 0)
// CHECK: ('extreloff', 0)
// CHECK: ('nextrel', 0)
// CHECK: ('locreloff', 0)
// CHECK: ('nlocrel', 0)
// CHECK: ('_indirect_symbols', [
// CHECK: ])
// CHECK: ),
// CHECK: ])