llvm-mc: Support .comm emission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80351 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Dunbar 2009-08-28 07:08:35 +00:00
parent d17479e845
commit 8f4d146c34
4 changed files with 191 additions and 15 deletions

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@ -452,6 +452,17 @@ public:
/// IsPrivateExtern - True if this symbol is private extern.
unsigned IsPrivateExtern : 1;
/// CommonSize - The size of the symbol, if it is 'common', or 0.
//
// FIXME: Pack this in with other fields? We could put it in offset, since a
// common symbol can never get a definition.
uint64_t CommonSize;
/// CommonAlign - The alignment of the symbol, if it is 'common'.
//
// FIXME: Pack this in with other fields?
unsigned CommonAlign;
/// Flags - The Flags field is used by object file implementations to store
/// additional per symbol information which is not easily classified.
uint32_t Flags;
@ -485,7 +496,31 @@ public:
bool isPrivateExtern() const { return IsPrivateExtern; }
void setPrivateExtern(bool Value) { IsPrivateExtern = Value; }
/// isCommon - Is this a 'common' symbol.
bool isCommon() const { return CommonSize != 0; }
/// setCommon - Mark this symbol as being 'common'.
///
/// \param Size - The size of the symbol.
/// \param Align - The alignment of the symbol.
void setCommon(uint64_t Size, unsigned Align) {
CommonSize = Size;
CommonAlign = Align;
}
/// getCommonSize - Return the size of a 'common' symbol.
uint64_t getCommonSize() const {
assert(isCommon() && "Not a 'common' symbol!");
return CommonSize;
}
/// getCommonAlignment - Return the alignment of a 'common' symbol.
unsigned getCommonAlignment() const {
assert(isCommon() && "Not a 'common' symbol!");
return CommonAlign;
}
/// getFlags - Get the (implementation defined) symbol flags.
uint32_t getFlags() const { return Flags; }

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@ -25,6 +25,11 @@ class MachObjectWriter;
STATISTIC(EmittedFragments, "Number of emitted assembler fragments");
// FIXME FIXME FIXME: There are number of places in this file where we convert
// what is a 64-bit assembler value used for computation into a value in the
// object file, which may truncate it. We should detect that truncation where
// invalid and report errors back.
static void WriteFileData(raw_ostream &OS, const MCSectionData &SD,
MachObjectWriter &MOW);
@ -328,6 +333,8 @@ public:
MCSymbolData &Data = *MSD.SymbolData;
MCSymbol &Symbol = Data.getSymbol();
uint8_t Type = 0;
uint16_t Flags = Data.getFlags();
uint32_t Address = 0;
// Set the N_TYPE bits. See <mach-o/nlist.h>.
//
@ -348,6 +355,30 @@ public:
if (Data.isExternal() || Symbol.isUndefined())
Type |= STF_External;
// Compute the symbol address.
if (Symbol.isDefined()) {
if (Symbol.isAbsolute()) {
llvm_unreachable("FIXME: Not yet implemented!");
} else {
Address = Data.getFragment()->getAddress() + Data.getOffset();
}
} else if (Data.isCommon()) {
// Common symbols are encoded with the size in the address
// field, and their alignment in the flags.
Address = Data.getCommonSize();
// Common alignment is packed into the 'desc' bits.
if (unsigned Align = Data.getCommonAlignment()) {
unsigned Log2Size = Log2_32(Align);
assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
if (Log2Size > 15)
llvm_report_error("invalid 'common' alignment '" +
Twine(Align) + "'");
// FIXME: Keep this mask with the SymbolFlags enumeration.
Flags = (Flags & 0xF0FF) | (Log2Size << 8);
}
}
// struct nlist (12 bytes)
Write32(MSD.StringIndex);
@ -356,17 +387,7 @@ public:
// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
// value.
Write16(Data.getFlags() & 0xFFFF);
// Write the symbol address.
uint32_t Address = 0;
if (Symbol.isDefined()) {
if (Symbol.isAbsolute()) {
llvm_unreachable("FIXME: Not yet implemented!");
} else {
Address = Data.getFragment()->getAddress() + Data.getOffset();
}
}
Write16(Flags);
Write32(Address);
}
@ -910,7 +931,8 @@ MCSymbolData::MCSymbolData() : Symbol(*(MCSymbol*)0) {}
MCSymbolData::MCSymbolData(MCSymbol &_Symbol, MCFragment *_Fragment,
uint64_t _Offset, MCAssembler *A)
: Symbol(_Symbol), Fragment(_Fragment), Offset(_Offset),
IsExternal(false), IsPrivateExtern(false), Flags(0), Index(0)
IsExternal(false), IsPrivateExtern(false),
CommonSize(0), CommonAlign(0), Flags(0), Index(0)
{
if (A)
A->getSymbolList().push_back(this);

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@ -224,7 +224,7 @@ void MCMachOStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
break;
case MCStreamer::Global:
getSymbolData(*Symbol).setExternal(true);
SD.setExternal(true);
break;
case MCStreamer::LazyReference:
@ -273,7 +273,12 @@ void MCMachOStreamer::EmitLocalSymbol(MCSymbol *Symbol, const MCValue &Value) {
void MCMachOStreamer::EmitCommonSymbol(MCSymbol *Symbol, unsigned Size,
unsigned Pow2Alignment) {
llvm_unreachable("FIXME: Not yet implemented!");
// FIXME: Darwin 'as' does appear to allow redef of a .comm by itself.
assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
MCSymbolData &SD = getSymbolData(*Symbol);
SD.setExternal(true);
SD.setCommon(Size, 1 << Pow2Alignment);
}
void MCMachOStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,

114
test/MC/MachO/comm-1.s Normal file
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@ -0,0 +1,114 @@
// RUN: llvm-mc -triple i386-apple-darwin9 %s -filetype=obj -o - | macho-dump | FileCheck %s
.comm sym_comm_B, 2
.comm sym_comm_A, 4
.comm sym_comm_C, 8, 2
.comm sym_comm_D, 2, 3
.no_dead_strip sym_comm_C
// CHECK: ('cputype', 7)
// CHECK: ('cpusubtype', 3)
// CHECK: ('filetype', 1)
// CHECK: ('num_load_commands', 1)
// CHECK: ('load_commands_size', 228)
// CHECK: ('flag', 0)
// CHECK: ('load_commands', [
// CHECK: # Load Command 0
// CHECK: (('command', 1)
// CHECK: ('size', 124)
// 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', 256)
// CHECK: ('file_size', 0)
// CHECK: ('maxprot', 7)
// CHECK: ('initprot', 7)
// CHECK: ('num_sections', 1)
// 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', 256)
// CHECK: ('alignment', 0)
// CHECK: ('reloc_offset', 0)
// CHECK: ('num_reloc', 0)
// CHECK: ('flags', 0x80000000)
// CHECK: ('reserved1', 0)
// CHECK: ('reserved2', 0)
// CHECK: ),
// CHECK: ('_relocations', [
// CHECK: ])
// CHECK: ])
// CHECK: ),
// CHECK: # Load Command 1
// CHECK: (('command', 2)
// CHECK: ('size', 24)
// CHECK: ('symoff', 256)
// CHECK: ('nsyms', 4)
// CHECK: ('stroff', 304)
// CHECK: ('strsize', 48)
// CHECK: ('_string_data', '\x00sym_comm_B\x00sym_comm_A\x00sym_comm_C\x00sym_comm_D\x00\x00\x00\x00')
// CHECK: ('_symbols', [
// CHECK: # Symbol 0
// CHECK: (('n_strx', 12)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 4)
// CHECK: ('_string', 'sym_comm_A')
// CHECK: ),
// CHECK: # Symbol 1
// CHECK: (('n_strx', 1)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 0)
// CHECK: ('n_value', 2)
// CHECK: ('_string', 'sym_comm_B')
// CHECK: ),
// CHECK: # Symbol 2
// CHECK: (('n_strx', 23)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 544)
// CHECK: ('n_value', 8)
// CHECK: ('_string', 'sym_comm_C')
// CHECK: ),
// CHECK: # Symbol 3
// CHECK: (('n_strx', 34)
// CHECK: ('n_type', 0x1)
// CHECK: ('n_sect', 0)
// CHECK: ('n_desc', 768)
// CHECK: ('n_value', 2)
// CHECK: ('_string', 'sym_comm_D')
// CHECK: ),
// CHECK: ])
// CHECK: ),
// CHECK: # Load Command 2
// CHECK: (('command', 11)
// CHECK: ('size', 80)
// CHECK: ('ilocalsym', 0)
// CHECK: ('nlocalsym', 0)
// CHECK: ('iextdefsym', 0)
// CHECK: ('nextdefsym', 0)
// CHECK: ('iundefsym', 0)
// CHECK: ('nundefsym', 4)
// 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: ])