llvm-mc: Support .comm emission.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80351 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/MC/MCAssembler.cpp b/lib/MC/MCAssembler.cpp
index 8057fcb..0d9b540 100644
--- a/lib/MC/MCAssembler.cpp
+++ b/lib/MC/MCAssembler.cpp
@@ -25,6 +25,11 @@
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 @@
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 @@
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 @@
// 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(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);