[llvm] 439f804 - Revert "[COFF] Add MC support for emitting IMAGE_WEAK_EXTERN_ANTI_DEPENDENCY symbols"

Zequan Wu via llvm-commits llvm-commits at lists.llvm.org
Thu Apr 27 07:03:08 PDT 2023


Author: Zequan Wu
Date: 2023-04-27T10:01:56-04:00
New Revision: 439f804c47051d19456d527c09d7a8d0fe345c09

URL: https://github.com/llvm/llvm-project/commit/439f804c47051d19456d527c09d7a8d0fe345c09
DIFF: https://github.com/llvm/llvm-project/commit/439f804c47051d19456d527c09d7a8d0fe345c09.diff

LOG: Revert "[COFF] Add MC support for emitting IMAGE_WEAK_EXTERN_ANTI_DEPENDENCY symbols"

This reverts commit 10c17c97ebaf81ac26f6830e51a7a57ddcf63cd2. It causes undefined symbol error on chromium windows build. A small repro was uploaded to the code review.

Added: 
    

Modified: 
    llvm/include/llvm/MC/MCDirectives.h
    llvm/include/llvm/MC/MCSymbol.h
    llvm/include/llvm/MC/MCSymbolCOFF.h
    llvm/lib/MC/MCAsmStreamer.cpp
    llvm/lib/MC/MCELFStreamer.cpp
    llvm/lib/MC/MCExpr.cpp
    llvm/lib/MC/MCMachOStreamer.cpp
    llvm/lib/MC/MCParser/AsmParser.cpp
    llvm/lib/MC/MCParser/COFFAsmParser.cpp
    llvm/lib/MC/MCWinCOFFStreamer.cpp
    llvm/lib/MC/WinCOFFObjectWriter.cpp
    llvm/test/MC/COFF/addrsig.s
    llvm/test/MC/COFF/alias.s

Removed: 
    llvm/test/MC/COFF/weak-anti-dep.s


################################################################################
diff  --git a/llvm/include/llvm/MC/MCDirectives.h b/llvm/include/llvm/MC/MCDirectives.h
index fcab56ff0a740..b9668a0c994fa 100644
--- a/llvm/include/llvm/MC/MCDirectives.h
+++ b/llvm/include/llvm/MC/MCDirectives.h
@@ -46,7 +46,6 @@ enum MCSymbolAttr {
   MCSA_WeakDefinition,          ///< .weak_definition (MachO)
   MCSA_WeakReference,           ///< .weak_reference (MachO)
   MCSA_WeakDefAutoPrivate,      ///< .weak_def_can_be_hidden (MachO)
-  MCSA_WeakAntiDep,             ///< .weak_anti_dep (COFF)
   MCSA_Memtag,                  ///< .memtag (ELF)
 };
 

diff  --git a/llvm/include/llvm/MC/MCSymbol.h b/llvm/include/llvm/MC/MCSymbol.h
index f59821d48dc3d..8954960e3b8c7 100644
--- a/llvm/include/llvm/MC/MCSymbol.h
+++ b/llvm/include/llvm/MC/MCSymbol.h
@@ -102,9 +102,6 @@ class MCSymbol {
   /// This symbol is private extern.
   mutable unsigned IsPrivateExtern : 1;
 
-  /// This symbol is weak external.
-  mutable unsigned IsWeakExternal : 1;
-
   /// LLVM RTTI discriminator. This is actually a SymbolKind enumerator, but is
   /// unsigned to avoid sign extension and achieve better bitpacking with MSVC.
   unsigned Kind : 3;
@@ -164,8 +161,8 @@ class MCSymbol {
   MCSymbol(SymbolKind Kind, const StringMapEntry<bool> *Name, bool isTemporary)
       : IsTemporary(isTemporary), IsRedefinable(false), IsUsed(false),
         IsRegistered(false), IsExternal(false), IsPrivateExtern(false),
-        IsWeakExternal(false), Kind(Kind), IsUsedInReloc(false),
-        SymbolContents(SymContentsUnset), CommonAlignLog2(0), Flags(0) {
+        Kind(Kind), IsUsedInReloc(false), SymbolContents(SymContentsUnset),
+        CommonAlignLog2(0), Flags(0) {
     Offset = 0;
     FragmentAndHasName.setInt(!!Name);
     if (Name)
@@ -397,10 +394,8 @@ class MCSymbol {
 
   MCFragment *getFragment(bool SetUsed = true) const {
     MCFragment *Fragment = FragmentAndHasName.getPointer();
-    if (Fragment || !isVariable() || isWeakExternal())
+    if (Fragment || !isVariable())
       return Fragment;
-    // If the symbol is a non-weak alias, get information about
-    // the aliasee. (Don't try to resolve weak aliases.)
     Fragment = getVariableValue(SetUsed)->findAssociatedFragment();
     FragmentAndHasName.setPointer(Fragment);
     return Fragment;
@@ -412,8 +407,6 @@ class MCSymbol {
   bool isPrivateExtern() const { return IsPrivateExtern; }
   void setPrivateExtern(bool Value) { IsPrivateExtern = Value; }
 
-  bool isWeakExternal() const { return IsWeakExternal; }
-
   /// print - Print the value to the stream \p OS.
   void print(raw_ostream &OS, const MCAsmInfo *MAI) const;
 

diff  --git a/llvm/include/llvm/MC/MCSymbolCOFF.h b/llvm/include/llvm/MC/MCSymbolCOFF.h
index 7f077c7986c01..b25993c32db6d 100644
--- a/llvm/include/llvm/MC/MCSymbolCOFF.h
+++ b/llvm/include/llvm/MC/MCSymbolCOFF.h
@@ -23,9 +23,8 @@ class MCSymbolCOFF : public MCSymbol {
     SF_ClassMask = 0x00FF,
     SF_ClassShift = 0,
 
-    SF_SafeSEH = 0x0100,
-    SF_WeakExternalCharacteristicsMask = 0x0E00,
-    SF_WeakExternalCharacteristicsShift = 9,
+    SF_WeakExternal = 0x0100,
+    SF_SafeSEH = 0x0200,
   };
 
 public:
@@ -46,14 +45,11 @@ class MCSymbolCOFF : public MCSymbol {
     modifyFlags(StorageClass << SF_ClassShift, SF_ClassMask);
   }
 
-  COFF::WeakExternalCharacteristics getWeakExternalCharacteristics() const {
-    return static_cast<COFF::WeakExternalCharacteristics>((getFlags() & SF_WeakExternalCharacteristicsMask) >>
-           SF_WeakExternalCharacteristicsShift);
+  bool isWeakExternal() const {
+    return getFlags() & SF_WeakExternal;
   }
-  void setIsWeakExternal(COFF::WeakExternalCharacteristics Characteristics) const {
-    IsWeakExternal = true;
-    modifyFlags(Characteristics << SF_WeakExternalCharacteristicsShift,
-                SF_WeakExternalCharacteristicsMask);
+  void setIsWeakExternal() const {
+    modifyFlags(SF_WeakExternal, SF_WeakExternal);
   }
 
   bool isSafeSEH() const {

diff  --git a/llvm/lib/MC/MCAsmStreamer.cpp b/llvm/lib/MC/MCAsmStreamer.cpp
index 6f21566a50f25..c11d28b746f60 100644
--- a/llvm/lib/MC/MCAsmStreamer.cpp
+++ b/llvm/lib/MC/MCAsmStreamer.cpp
@@ -772,9 +772,6 @@ bool MCAsmStreamer::emitSymbolAttribute(MCSymbol *Symbol,
   case MCSA_Memtag:
     OS << "\t.memtag\t";
     break;
-  case MCSA_WeakAntiDep:
-    OS << "\t.weak_anti_dep\t";
-    break;
   }
 
   Symbol->print(OS, MAI);

diff  --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 303eb16011d17..8dd002fba0e1a 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/lib/MC/MCELFStreamer.cpp
@@ -216,7 +216,6 @@ bool MCELFStreamer::emitSymbolAttribute(MCSymbol *S, MCSymbolAttr Attribute) {
   case MCSA_Invalid:
   case MCSA_IndirectSymbol:
   case MCSA_Exported:
-  case MCSA_WeakAntiDep:
     return false;
 
   case MCSA_NoDeadStrip:

diff  --git a/llvm/lib/MC/MCExpr.cpp b/llvm/lib/MC/MCExpr.cpp
index 68cd88f822066..04682fdc7ecec 100644
--- a/llvm/lib/MC/MCExpr.cpp
+++ b/llvm/lib/MC/MCExpr.cpp
@@ -761,9 +761,6 @@ bool MCExpr::evaluateAsValue(MCValue &Res, const MCAsmLayout &Layout) const {
 }
 
 static bool canExpand(const MCSymbol &Sym, bool InSet) {
-  if (Sym.isWeakExternal())
-    return false;
-
   const MCExpr *Expr = Sym.getVariableValue();
   const auto *Inner = dyn_cast<MCSymbolRefExpr>(Expr);
   if (Inner) {

diff  --git a/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 6711ff9001a32..986c0c2c506bf 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/lib/MC/MCMachOStreamer.cpp
@@ -358,7 +358,6 @@ bool MCMachOStreamer::emitSymbolAttribute(MCSymbol *Sym,
   case MCSA_LGlobal:
   case MCSA_Exported:
   case MCSA_Memtag:
-  case MCSA_WeakAntiDep:
     return false;
 
   case MCSA_Global:

diff  --git a/llvm/lib/MC/MCParser/AsmParser.cpp b/llvm/lib/MC/MCParser/AsmParser.cpp
index 254c747aca050..c49e51332b126 100644
--- a/llvm/lib/MC/MCParser/AsmParser.cpp
+++ b/llvm/lib/MC/MCParser/AsmParser.cpp
@@ -6371,7 +6371,7 @@ static bool isSymbolUsedInExpression(const MCSymbol *Sym, const MCExpr *Value) {
   case MCExpr::SymbolRef: {
     const MCSymbol &S =
         static_cast<const MCSymbolRefExpr *>(Value)->getSymbol();
-    if (S.isVariable() && !S.isWeakExternal())
+    if (S.isVariable())
       return isSymbolUsedInExpression(Sym, S.getVariableValue());
     return &S == Sym;
   }

diff  --git a/llvm/lib/MC/MCParser/COFFAsmParser.cpp b/llvm/lib/MC/MCParser/COFFAsmParser.cpp
index 3f88257d37db9..fc3d1e94e49f7 100644
--- a/llvm/lib/MC/MCParser/COFFAsmParser.cpp
+++ b/llvm/lib/MC/MCParser/COFFAsmParser.cpp
@@ -67,7 +67,6 @@ class COFFAsmParser : public MCAsmParserExtension {
     addDirectiveHandler<&COFFAsmParser::ParseDirectiveLinkOnce>(".linkonce");
     addDirectiveHandler<&COFFAsmParser::ParseDirectiveRVA>(".rva");
     addDirectiveHandler<&COFFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
-    addDirectiveHandler<&COFFAsmParser::ParseDirectiveSymbolAttribute>(".weak_anti_dep");
     addDirectiveHandler<&COFFAsmParser::ParseDirectiveCGProfile>(".cg_profile");
 
     // Win64 EH directives.
@@ -282,7 +281,6 @@ bool COFFAsmParser::ParseSectionFlags(StringRef SectionName,
 bool COFFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
   MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
     .Case(".weak", MCSA_Weak)
-    .Case(".weak_anti_dep", MCSA_WeakAntiDep)
     .Default(MCSA_Invalid);
   assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
   if (getLexer().isNot(AsmToken::EndOfStatement)) {

diff  --git a/llvm/lib/MC/MCWinCOFFStreamer.cpp b/llvm/lib/MC/MCWinCOFFStreamer.cpp
index ad0b1c157278a..c9a9681648341 100644
--- a/llvm/lib/MC/MCWinCOFFStreamer.cpp
+++ b/llvm/lib/MC/MCWinCOFFStreamer.cpp
@@ -115,11 +115,7 @@ bool MCWinCOFFStreamer::emitSymbolAttribute(MCSymbol *S,
   default: return false;
   case MCSA_WeakReference:
   case MCSA_Weak:
-    Symbol->setIsWeakExternal(COFF::IMAGE_WEAK_EXTERN_SEARCH_ALIAS);
-    Symbol->setExternal(true);
-    break;
-  case MCSA_WeakAntiDep:
-    Symbol->setIsWeakExternal(COFF::IMAGE_WEAK_EXTERN_ANTI_DEPENDENCY);
+    Symbol->setIsWeakExternal();
     Symbol->setExternal(true);
     break;
   case MCSA_Global:

diff  --git a/llvm/lib/MC/WinCOFFObjectWriter.cpp b/llvm/lib/MC/WinCOFFObjectWriter.cpp
index c18a963280911..07de8cdb98ac7 100644
--- a/llvm/lib/MC/WinCOFFObjectWriter.cpp
+++ b/llvm/lib/MC/WinCOFFObjectWriter.cpp
@@ -414,9 +414,9 @@ void WinCOFFObjectWriter::DefineSymbol(const MCSymbol &MCSym,
     Sym->Aux.resize(1);
     memset(&Sym->Aux[0], 0, sizeof(Sym->Aux[0]));
     Sym->Aux[0].AuxType = ATWeakExternal;
-    Sym->Aux[0].Aux.WeakExternal.TagIndex = 0; // Filled in later
+    Sym->Aux[0].Aux.WeakExternal.TagIndex = 0;
     Sym->Aux[0].Aux.WeakExternal.Characteristics =
-        cast<MCSymbolCOFF>(MCSym).getWeakExternalCharacteristics();
+        COFF::IMAGE_WEAK_EXTERN_SEARCH_ALIAS;
   } else {
     if (!Base)
       Sym->Data.SectionNumber = COFF::IMAGE_SYM_ABSOLUTE;

diff  --git a/llvm/test/MC/COFF/addrsig.s b/llvm/test/MC/COFF/addrsig.s
index a181bb06508be..7c3b25d52edae 100644
--- a/llvm/test/MC/COFF/addrsig.s
+++ b/llvm/test/MC/COFF/addrsig.s
@@ -3,7 +3,7 @@
 // CHECK:      Name: .llvm_addrsig
 // CHECK-NEXT: VirtualSize: 0x0
 // CHECK-NEXT: VirtualAddress: 0x0
-// CHECK-NEXT: RawDataSize: 6
+// CHECK-NEXT: RawDataSize: 4
 // CHECK-NEXT: PointerToRawData:
 // CHECK-NEXT: PointerToRelocations: 0x0
 // CHECK-NEXT: PointerToLineNumbers: 0x0
@@ -46,8 +46,6 @@
 // CHECK-NEXT:   Sym: g3 (11)
 // CHECK-NEXT:   Sym: local (10)
 // CHECK-NEXT:   Sym: .data (2)
-// CHECK-NEXT:   Sym: weak_sym (12)
-// CHECK-NEXT:   Sym: .data (2)
 // CHECK-NEXT: ]
 
 .globl g1
@@ -66,10 +64,3 @@ local:
 
 .data
 .Llocal:
-
-.weak weak_sym
-weak_sym:
-.addrsig_sym weak_sym
-
-.set .Lalias_weak_sym, weak_sym
-.addrsig_sym .Lalias_weak_sym

diff  --git a/llvm/test/MC/COFF/alias.s b/llvm/test/MC/COFF/alias.s
index cfb44ca1503fe..b6828c658132b 100644
--- a/llvm/test/MC/COFF/alias.s
+++ b/llvm/test/MC/COFF/alias.s
@@ -24,7 +24,7 @@ weak_aliased_to_external = external2
 // CHECK:        0x0 IMAGE_REL_I386_DIR32 external_aliased_to_local
 // CHECK:        0x4 IMAGE_REL_I386_DIR32 external1
 // CHECK:        0x8 IMAGE_REL_I386_DIR32 global_aliased_to_local
-// CHECK:        0xC IMAGE_REL_I386_DIR32 weak_aliased_to_external
+// CHECK:        0xC IMAGE_REL_I386_DIR32 external2
 // CHECK:      ]
 // CHECK:      Symbols [
 // CHECK-NEXT:   Symbol {

diff  --git a/llvm/test/MC/COFF/weak-anti-dep.s b/llvm/test/MC/COFF/weak-anti-dep.s
deleted file mode 100644
index dbf5ffc0a35bf..0000000000000
--- a/llvm/test/MC/COFF/weak-anti-dep.s
+++ /dev/null
@@ -1,68 +0,0 @@
-// RUN: llvm-mc -filetype=obj -triple x86_64-pc-win32 %s | llvm-readobj --symbols - | FileCheck %s
-
-// CHECK:       Symbol {
-// CHECK-NEXT:    Name: .text
-// CHECK:       Symbol {
-// CHECK-NEXT:    Name: .data
-// CHECK:       Symbol {
-// CHECK-NEXT:    Name: .bss
-
-.weak_anti_dep a
-a = b
-
-// CHECK:       Symbol {
-// CHECK-NEXT:    Name: a
-// CHECK-NEXT:    Value: 0
-// CHECK-NEXT:    Section: IMAGE_SYM_UNDEFINED (0)
-// CHECK-NEXT:    BaseType: Null (0x0)
-// CHECK-NEXT:    ComplexType: Null (0x0)
-// CHECK-NEXT:    StorageClass: WeakExternal (0x69)
-// CHECK-NEXT:    AuxSymbolCount: 1
-// CHECK-NEXT:    AuxWeakExternal {
-// CHECK-NEXT:      Linked: b (8)
-// CHECK-NEXT:      Search: AntiDependency (0x4)
-// CHECK-NEXT:    }
-// CHECK-NEXT:  }
-// CHECK-NEXT:  Symbol {
-// CHECK-NEXT:    Name: b
-// CHECK-NEXT:    Value: 0
-// CHECK-NEXT:    Section: IMAGE_SYM_UNDEFINED (0)
-// CHECK-NEXT:    BaseType: Null (0x0)
-// CHECK-NEXT:    ComplexType: Null (0x0)
-// CHECK-NEXT:    StorageClass: External (0x2)
-// CHECK-NEXT:    AuxSymbolCount: 0
-// CHECK-NEXT:  }
-
-
-.weak_anti_dep r1
-.weak_anti_dep r2
-r1 = r2
-r2 = r1
-
-
-// CHECK:       Symbol {
-// CHECK-NEXT:    Name: r1
-// CHECK-NEXT:    Value: 0
-// CHECK-NEXT:    Section: IMAGE_SYM_UNDEFINED (0)
-// CHECK-NEXT:    BaseType: Null (0x0)
-// CHECK-NEXT:    ComplexType: Null (0x0)
-// CHECK-NEXT:    StorageClass: WeakExternal (0x69)
-// CHECK-NEXT:    AuxSymbolCount: 1
-// CHECK-NEXT:    AuxWeakExternal {
-// CHECK-NEXT:      Linked: r2 (11)
-// CHECK-NEXT:      Search: AntiDependency (0x4)
-// CHECK-NEXT:    }
-// CHECK-NEXT:  }
-// CHECK-NEXT:  Symbol {
-// CHECK-NEXT:    Name: r2
-// CHECK-NEXT:    Value: 0
-// CHECK-NEXT:    Section: IMAGE_SYM_UNDEFINED (0)
-// CHECK-NEXT:    BaseType: Null (0x0)
-// CHECK-NEXT:    ComplexType: Null (0x0)
-// CHECK-NEXT:    StorageClass: WeakExternal (0x69)
-// CHECK-NEXT:    AuxSymbolCount: 1
-// CHECK-NEXT:    AuxWeakExternal {
-// CHECK-NEXT:      Linked: r1 (9)
-// CHECK-NEXT:      Search: AntiDependency (0x4)
-// CHECK-NEXT:    }
-// CHECK-NEXT:  }


        


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