Don't drop alignment info on local common symbols.

- On COFF the .lcomm directive has an alignment argument.
- On ELF we fall back to .local + .comm

Based on a patch by NAKAMURA Takumi.

Fixes PR9337, PR9483 and PR10128.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138976 91177308-0d34-0410-b5e6-96231b3b80d8

10 files changed, 33 insertions, 18 deletions

diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index 015ccd4..a53c474 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -65,7 +65,7 @@ MCAsmInfo::MCAsmInfo() {
   GlobalDirective = "\t.globl\t";
   HasSetDirective = true;
   HasAggressiveSymbolFolding = true;
-  HasLCOMMDirective = false;
+  LCOMMDirectiveType = LCOMM::None;
   COMMDirectiveAlignmentIsInBytes = true;
   HasDotTypeDotSizeDirective = true;
   HasSingleParameterDotFile = true;
diff --git a/lib/MC/MCAsmInfoCOFF.cpp b/lib/MC/MCAsmInfoCOFF.cpp
index 7fc7d7a..cf6026b 100644
--- a/lib/MC/MCAsmInfoCOFF.cpp
+++ b/lib/MC/MCAsmInfoCOFF.cpp
@@ -19,7 +19,7 @@ using namespace llvm;
 MCAsmInfoCOFF::MCAsmInfoCOFF() {
   GlobalPrefix = "_";
   COMMDirectiveAlignmentIsInBytes = false;
-  HasLCOMMDirective = true;
+  LCOMMDirectiveType = LCOMM::ByteAlignment;
   HasDotTypeDotSizeDirective = false;
   HasSingleParameterDotFile = false;
   PrivateGlobalPrefix = "L";  // Prefix for private global symbols
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 40eaf97..6815434 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -158,7 +158,9 @@ public:
   ///
   /// @param Symbol - The common symbol to emit.
   /// @param Size - The size of the common symbol.
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
+  /// @param Size - The alignment of the common symbol in bytes.
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment);
 
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
                             unsigned Size = 0, unsigned ByteAlignment = 0);
@@ -484,9 +486,16 @@ void MCAsmStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
 ///
 /// @param Symbol - The common symbol to emit.
 /// @param Size - The size of the common symbol.
-void MCAsmStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
-  assert(MAI.hasLCOMMDirective() && "Doesn't have .lcomm, can't emit it!");
+void MCAsmStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                          unsigned ByteAlign) {
+  assert(MAI.getLCOMMDirectiveType() != LCOMM::None &&
+         "Doesn't have .lcomm, can't emit it!");
   OS << "\t.lcomm\t" << *Symbol << ',' << Size;
+  if (ByteAlign > 1) {
+    assert(MAI.getLCOMMDirectiveType() == LCOMM::ByteAlignment &&
+           "Alignment not supported on .lcomm!");
+    OS << ',' << ByteAlign;
+  }
   EmitEOL();
 }
 
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 573b3e4..9ada08e 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -220,14 +220,14 @@ void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
   SD.setSize(MCConstantExpr::Create(Size, getContext()));
 }
 
-void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                          unsigned ByteAlignment) {
   // FIXME: Should this be caught and done earlier?
   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
   MCELF::SetBinding(SD, ELF::STB_LOCAL);
   SD.setExternal(false);
   BindingExplicitlySet.insert(Symbol);
-  // FIXME: ByteAlignment is not needed here, but is required.
-  EmitCommonSymbol(Symbol, Size, 1);
+  EmitCommonSymbol(Symbol, Size, ByteAlignment);
 }
 
 void MCELFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
diff --git a/lib/MC/MCELFStreamer.h b/lib/MC/MCELFStreamer.h
index 9b5f3a8..10bf775 100644
--- a/lib/MC/MCELFStreamer.h
+++ b/lib/MC/MCELFStreamer.h
@@ -74,7 +74,8 @@ public:
      SD.setSize(Value);
   }
 
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment);
 
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
                             unsigned Size = 0, unsigned ByteAlignment = 0) {
diff --git a/lib/MC/MCLoggingStreamer.cpp b/lib/MC/MCLoggingStreamer.cpp
index 309752e..3fe8ac7 100644
--- a/lib/MC/MCLoggingStreamer.cpp
+++ b/lib/MC/MCLoggingStreamer.cpp
@@ -133,9 +133,10 @@ public:
     return Child->EmitCommonSymbol(Symbol, Size, ByteAlignment);
   }
 
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment) {
     LogCall("EmitLocalCommonSymbol");
-    return Child->EmitLocalCommonSymbol(Symbol, Size);
+    return Child->EmitLocalCommonSymbol(Symbol, Size, ByteAlignment);
   }
   
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 844793b..aa35815 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -67,7 +67,8 @@ public:
   virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
     assert(0 && "macho doesn't support this directive");
   }
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment) {
     assert(0 && "macho doesn't support this directive");
   }
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
diff --git a/lib/MC/MCNullStreamer.cpp b/lib/MC/MCNullStreamer.cpp
index 9577af0..a6c0adb 100644
--- a/lib/MC/MCNullStreamer.cpp
+++ b/lib/MC/MCNullStreamer.cpp
@@ -59,8 +59,8 @@ namespace {
     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                   unsigned ByteAlignment) {}
-    virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {}
-
+    virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                       unsigned ByteAlignment) {}
     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
                               unsigned Size = 0, unsigned ByteAlignment = 0) {}
     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
diff --git a/lib/MC/MCPureStreamer.cpp b/lib/MC/MCPureStreamer.cpp
index 0b61c88..086c922 100644
--- a/lib/MC/MCPureStreamer.cpp
+++ b/lib/MC/MCPureStreamer.cpp
@@ -86,7 +86,8 @@ public:
   virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
     report_fatal_error("unsupported directive in pure streamer");
   }
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment) {
     report_fatal_error("unsupported directive in pure streamer");
   }
   virtual void EmitFileDirective(StringRef Filename) {
diff --git a/lib/MC/WinCOFFStreamer.cpp b/lib/MC/WinCOFFStreamer.cpp
index f79ba8e..7409daf 100644
--- a/lib/MC/WinCOFFStreamer.cpp
+++ b/lib/MC/WinCOFFStreamer.cpp
@@ -63,7 +63,8 @@ public:
   virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
   virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                 unsigned ByteAlignment);
-  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size);
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment);
   virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
                             unsigned Size,unsigned ByteAlignment);
   virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
@@ -304,11 +305,12 @@ void WinCOFFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
   AddCommonSymbol(Symbol, Size, ByteAlignment, true);
 }
 
-void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) {
+void WinCOFFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                            unsigned ByteAlignment) {
   assert((Symbol->isInSection()
          ? Symbol->getSection().getVariant() == MCSection::SV_COFF
          : true) && "Got non COFF section in the COFF backend!");
-  AddCommonSymbol(Symbol, Size, 1, false);
+  AddCommonSymbol(Symbol, Size, ByteAlignment, false);
 }
 
 void WinCOFFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,