[llvm] r209894 - MachO: support N_INDR aliases in assembly files.
Tim Northover
tnorthover at apple.com
Fri May 30 06:23:00 PDT 2014
Author: tnorthover
Date: Fri May 30 08:22:59 2014
New Revision: 209894
URL: http://llvm.org/viewvc/llvm-project?rev=209894&view=rev
Log:
MachO: support N_INDR aliases in assembly files.
This makes LLVM create N_INDR aliases (to be resolved by the linker) when
appropriate.
rdar://problem/15125513
Added:
llvm/trunk/test/MC/MachO/aliased-symbols.s
Modified:
llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
llvm/trunk/include/llvm/Object/SymbolicFile.h
llvm/trunk/lib/MC/MachObjectWriter.cpp
llvm/trunk/lib/Object/MachOObjectFile.cpp
llvm/trunk/test/MC/MachO/variable-exprs.s
llvm/trunk/tools/llvm-nm/llvm-nm.cpp
Modified: llvm/trunk/include/llvm/MC/MCMachObjectWriter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/MC/MCMachObjectWriter.h?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/include/llvm/MC/MCMachObjectWriter.h (original)
+++ llvm/trunk/include/llvm/MC/MCMachObjectWriter.h Fri May 30 08:22:59 2014
@@ -111,6 +111,8 @@ class MachObjectWriter : public MCObject
/// @}
+ MachSymbolData *findSymbolData(const MCSymbol &Sym);
+
public:
MachObjectWriter(MCMachObjectTargetWriter *MOTW, raw_ostream &_OS,
bool _IsLittleEndian)
Modified: llvm/trunk/include/llvm/Object/SymbolicFile.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/SymbolicFile.h?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Object/SymbolicFile.h (original)
+++ llvm/trunk/include/llvm/Object/SymbolicFile.h Fri May 30 08:22:59 2014
@@ -86,6 +86,7 @@ public:
SF_Weak = 1U << 2, // Weak symbol
SF_Absolute = 1U << 3, // Absolute symbol
SF_Common = 1U << 4, // Symbol has common linkage
+ SF_Indirect = 1U << 5,
SF_FormatSpecific = 1U << 5 // Specific to the object file format
// (e.g. section symbols)
};
Modified: llvm/trunk/lib/MC/MachObjectWriter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/MC/MachObjectWriter.cpp?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/lib/MC/MachObjectWriter.cpp (original)
+++ llvm/trunk/lib/MC/MachObjectWriter.cpp Fri May 30 08:22:59 2014
@@ -303,20 +303,50 @@ void MachObjectWriter::WriteDysymtabLoad
assert(OS.tell() - Start == sizeof(MachO::dysymtab_command));
}
+MachObjectWriter::MachSymbolData *
+MachObjectWriter::findSymbolData(const MCSymbol &Sym) {
+ for (auto &Entry : LocalSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ for (auto &Entry : ExternalSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ for (auto &Entry : UndefinedSymbolData)
+ if (&Entry.SymbolData->getSymbol() == &Sym)
+ return &Entry;
+
+ return nullptr;
+}
+
void MachObjectWriter::WriteNlist(MachSymbolData &MSD,
const MCAsmLayout &Layout) {
MCSymbolData &Data = *MSD.SymbolData;
- const MCSymbol &Symbol = Data.getSymbol();
+ const MCSymbol *Symbol = &Data.getSymbol();
+ const MCSymbol *AliasedSymbol = &Symbol->AliasedSymbol();
+ uint8_t SectionIndex = MSD.SectionIndex;
uint8_t Type = 0;
uint16_t Flags = Data.getFlags();
uint64_t Address = 0;
+ bool IsAlias = Symbol != AliasedSymbol;
+
+ MachSymbolData *AliaseeInfo;
+ if (IsAlias) {
+ AliaseeInfo = findSymbolData(*AliasedSymbol);
+ if (AliaseeInfo)
+ SectionIndex = AliaseeInfo->SectionIndex;
+ Symbol = AliasedSymbol;
+ }
// Set the N_TYPE bits. See <mach-o/nlist.h>.
//
// FIXME: Are the prebound or indirect fields possible here?
- if (Symbol.isUndefined())
+ if (IsAlias && Symbol->isUndefined())
+ Type = MachO::N_INDR;
+ else if (Symbol->isUndefined())
Type = MachO::N_UNDF;
- else if (Symbol.isAbsolute())
+ else if (Symbol->isAbsolute())
Type = MachO::N_ABS;
else
Type = MachO::N_SECT;
@@ -327,13 +357,15 @@ void MachObjectWriter::WriteNlist(MachSy
Type |= MachO::N_PEXT;
// Set external bit.
- if (Data.isExternal() || Symbol.isUndefined())
+ if (Data.isExternal() || (!IsAlias && Symbol->isUndefined()))
Type |= MachO::N_EXT;
// Compute the symbol address.
- if (Symbol.isDefined()) {
+ if (IsAlias && Symbol->isUndefined())
+ Address = AliaseeInfo->StringIndex;
+ else if (Symbol->isDefined())
Address = getSymbolAddress(&Data, Layout);
- } else if (Data.isCommon()) {
+ else if (Data.isCommon()) {
// Common symbols are encoded with the size in the address
// field, and their alignment in the flags.
Address = Data.getCommonSize();
@@ -344,21 +376,21 @@ void MachObjectWriter::WriteNlist(MachSy
assert((1U << Log2Size) == Align && "Invalid 'common' alignment!");
if (Log2Size > 15)
report_fatal_error("invalid 'common' alignment '" +
- Twine(Align) + "' for '" + Symbol.getName() + "'",
+ Twine(Align) + "' for '" + Symbol->getName() + "'",
false);
// FIXME: Keep this mask with the SymbolFlags enumeration.
Flags = (Flags & 0xF0FF) | (Log2Size << 8);
}
}
- if (Layout.getAssembler().isThumbFunc(&Symbol))
+ if (Layout.getAssembler().isThumbFunc(Symbol))
Flags |= SF_ThumbFunc;
// struct nlist (12 bytes)
Write32(MSD.StringIndex);
Write8(Type);
- Write8(MSD.SectionIndex);
+ Write8(SectionIndex);
// The Mach-O streamer uses the lowest 16-bits of the flags for the 'desc'
// value.
Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
+++ llvm/trunk/lib/Object/MachOObjectFile.cpp Fri May 30 08:22:59 2014
@@ -584,6 +584,9 @@ uint32_t MachOObjectFile::getSymbolFlags
if ((MachOType & MachO::N_TYPE) == MachO::N_UNDF)
Result |= SymbolRef::SF_Undefined;
+ if ((MachOType & MachO::N_TYPE) == MachO::N_INDR)
+ Result |= SymbolRef::SF_Indirect;
+
if (MachOType & MachO::N_STAB)
Result |= SymbolRef::SF_FormatSpecific;
Added: llvm/trunk/test/MC/MachO/aliased-symbols.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/aliased-symbols.s?rev=209894&view=auto
==============================================================================
--- llvm/trunk/test/MC/MachO/aliased-symbols.s (added)
+++ llvm/trunk/test/MC/MachO/aliased-symbols.s Fri May 30 08:22:59 2014
@@ -0,0 +1,115 @@
+// RUN: llvm-mc -triple thumbv7m-apple-darwin-eabi %s -filetype=obj -o %t
+// RUN: llvm-readobj -symbols %t | FileCheck %s
+
+ .data
+ var1 = var2
+ .long var1
+ .long var2
+ .long var2 + 4
+defined_early:
+ .long 0
+
+ alias_to_early = defined_early
+ alias_to_late = defined_late
+
+defined_late:
+ .long 0
+
+ .global extern_test
+ extern_test = var2
+
+ alias_to_local = Ltmp0
+Ltmp0:
+
+// CHECK: Symbols [
+
+ // defined_early was defined. Actually has value 0xc.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: defined_early
+// CHECK-NEXT: Type: Section (0xE)
+// CHECK-NEXT: Section: __data (0x2)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[DEFINED_EARLY:[0-9A-F]+]]
+// CHECK-NEXT: }
+
+ // alias_to_early was an alias to defined_early. But we can resolve it.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: alias_to_early
+// CHECK-NEXT: Type: Section (0xE)
+// CHECK-NEXT: Section: __data (0x2)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[DEFINED_EARLY]]
+// CHECK-NEXT: }
+
+ // defined_late was defined. Just after defined_early.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: defined_late
+// CHECK-NEXT: Type: Section (0xE)
+// CHECK-NEXT: Section: __data (0x2)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[DEFINED_LATE:[0-9A-F]+]]
+// CHECK-NEXT: }
+
+ // alias_to_late was an alias to defined_late. But we can resolve it.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: alias_to_late
+// CHECK-NEXT: Type: Section (0xE)
+// CHECK-NEXT: Section: __data (0x2)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[DEFINED_LATE]]
+// CHECK-NEXT: }
+
+ // alias_to_local is an alias, but what it points to has no
+ // MachO representation. We must resolve it.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: alias_to_local (37)
+// CHECK-NEXT: Type: Section (0xE)
+// CHECK-NEXT: Section: (0x0)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x14
+// CHECK-NEXT: }
+
+ // extern_test was a pure alias to the unknown "var2".
+ // N_INDR and Extern.
+// CHECK: Name: extern_test
+// CHECK-NEXT: Extern
+// CHECK-NEXT: Type: Indirect (0xA)
+// CHECK-NEXT: Section: (0x0)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[VAR2_STRINGINDEX:[0-9a-f]+]]
+// CHECK-NEXT: }
+
+ // var1 was another alias to an unknown variable. Not extern this time.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: var1 (1)
+// CHECK-NEXT: Type: Indirect (0xA)
+// CHECK-NEXT: Section: (0x0)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x[[VAR2_STRINGINDEX]]
+// CHECK-NEXT: }
+
+ // var2 was a normal undefined (extern) symbol.
+// CHECK: Symbol {
+// CHECK-NEXT: Name: var2
+// CHECK-NEXT: Extern
+// CHECK-NEXT: Type: Undef (0x0)
+// CHECK-NEXT: Section: (0x0)
+// CHECK-NEXT: RefType: UndefinedNonLazy (0x0)
+// CHECK-NEXT: Flags [ (0x0)
+// CHECK-NEXT: ]
+// CHECK-NEXT: Value: 0x0
+// CHECK-NEXT: }
Modified: llvm/trunk/test/MC/MachO/variable-exprs.s
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/MC/MachO/variable-exprs.s?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/test/MC/MachO/variable-exprs.s (original)
+++ llvm/trunk/test/MC/MachO/variable-exprs.s Fri May 30 08:22:59 2014
@@ -202,10 +202,10 @@ Lt0_x = Lt0_a - Lt0_b
// CHECK-I386: ),
// CHECK-I386: # Symbol 8
// CHECK-I386: (('n_strx', 1)
-// CHECK-I386: ('n_type', 0x1)
+// CHECK-I386: ('n_type', 0xb)
// CHECK-I386: ('n_sect', 0)
// CHECK-I386: ('n_desc', 0)
-// CHECK-I386: ('n_value', 0)
+// CHECK-I386: ('n_value', 4)
// CHECK-I386: ('_string', 'd2')
// CHECK-I386: ),
// CHECK-I386: # Symbol 9
@@ -403,10 +403,10 @@ Lt0_x = Lt0_a - Lt0_b
// CHECK-X86_64: ),
// CHECK-X86_64: # Symbol 8
// CHECK-X86_64: (('n_strx', 1)
-// CHECK-X86_64: ('n_type', 0x1)
+// CHECK-X86_64: ('n_type', 0xb)
// CHECK-X86_64: ('n_sect', 0)
// CHECK-X86_64: ('n_desc', 0)
-// CHECK-X86_64: ('n_value', 0)
+// CHECK-X86_64: ('n_value', 4)
// CHECK-X86_64: ('_string', 'd2')
// CHECK-X86_64: ),
// CHECK-X86_64: # Symbol 9
Modified: llvm/trunk/tools/llvm-nm/llvm-nm.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-nm/llvm-nm.cpp?rev=209894&r1=209893&r2=209894&view=diff
==============================================================================
--- llvm/trunk/tools/llvm-nm/llvm-nm.cpp (original)
+++ llvm/trunk/tools/llvm-nm/llvm-nm.cpp Fri May 30 08:22:59 2014
@@ -395,6 +395,8 @@ static char getSymbolNMTypeChar(MachOObj
switch (NType & MachO::N_TYPE) {
case MachO::N_ABS:
return 's';
+ case MachO::N_INDR:
+ return 'i';
case MachO::N_SECT: {
section_iterator Sec = Obj.section_end();
Obj.getSymbolSection(Symb, Sec);
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