Fix alignment of .comm and .lcomm on mingw32.

For some reason .lcomm uses byte alignment and .comm log2 alignment so we can't
use the same setting for both. Fix this by reintroducing the LCOMM enum.
I verified this against mingw's gcc.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163420 91177308-0d34-0410-b5e6-96231b3b80d8

9 files changed, 42 insertions, 17 deletions

diff --git a/include/llvm/MC/MCAsmInfo.h b/include/llvm/MC/MCAsmInfo.h
index 73709364fe..97aad71fd9 100644
--- a/include/llvm/MC/MCAsmInfo.h
+++ b/include/llvm/MC/MCAsmInfo.h
@@ -32,6 +32,10 @@ namespace llvm {
     enum ExceptionsType { None, DwarfCFI, SjLj, ARM, Win64 };
   }
 
+  namespace LCOMM {
+    enum LCOMMType { NoAlignment, ByteAlignment, Log2Alignment };
+  }
+
   /// MCAsmInfo - This class is intended to be used as a base class for asm
   /// properties and features specific to the target.
   class MCAsmInfo {
@@ -247,9 +251,9 @@ namespace llvm {
     /// alignment is to be specified in bytes instead of log2(n).
     bool COMMDirectiveAlignmentIsInBytes;    // Defaults to true;
 
-    /// LCOMMDirectiveSupportsAlignment - True if .lcomm supports an optional
-    /// alignment argument on this target.
-    bool LCOMMDirectiveSupportsAlignment;    // Defaults to false.
+    /// LCOMMDirectiveAlignment - Describes if the .lcomm directive for the
+    /// target supports an alignment argument and how it is interpreted.
+    LCOMM::LCOMMType LCOMMDirectiveAlignmentType; // Defaults to NoAlignment.
 
     /// HasDotTypeDotSizeDirective - True if the target has .type and .size
     /// directives, this is true for most ELF targets.
@@ -495,8 +499,8 @@ namespace llvm {
     bool getCOMMDirectiveAlignmentIsInBytes() const {
       return COMMDirectiveAlignmentIsInBytes;
     }
-    bool getLCOMMDirectiveSupportsAlignment() const {
-      return LCOMMDirectiveSupportsAlignment;
+    LCOMM::LCOMMType getLCOMMDirectiveAlignmentType() const {
+      return LCOMMDirectiveAlignmentType;
     }
     bool hasDotTypeDotSizeDirective() const {return HasDotTypeDotSizeDirective;}
     bool hasSingleParameterDotFile() const { return HasSingleParameterDotFile; }
diff --git a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 2aae37696b..d6d4510409 100644
--- a/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -312,7 +312,8 @@ void AsmPrinter::EmitGlobalVariable(const GlobalVariable *GV) {
       return;
     }
 
-    if (Align == 1 || MAI->getLCOMMDirectiveSupportsAlignment()) {
+    if (Align == 1 ||
+        MAI->getLCOMMDirectiveAlignmentType() != LCOMM::NoAlignment) {
       // .lcomm _foo, 42
       OutStreamer.EmitLocalCommonSymbol(GVSym, Size, Align);
       return;
diff --git a/lib/MC/MCAsmInfo.cpp b/lib/MC/MCAsmInfo.cpp
index 11e368c81a..7ea0f3b85a 100644
--- a/lib/MC/MCAsmInfo.cpp
+++ b/lib/MC/MCAsmInfo.cpp
@@ -69,7 +69,7 @@ MCAsmInfo::MCAsmInfo() {
   HasSetDirective = true;
   HasAggressiveSymbolFolding = true;
   COMMDirectiveAlignmentIsInBytes = true;
-  LCOMMDirectiveSupportsAlignment = false;
+  LCOMMDirectiveAlignmentType = LCOMM::NoAlignment;
   HasDotTypeDotSizeDirective = true;
   HasSingleParameterDotFile = true;
   HasNoDeadStrip = false;
diff --git a/lib/MC/MCAsmInfoCOFF.cpp b/lib/MC/MCAsmInfoCOFF.cpp
index 4b426f8a73..fd79193073 100644
--- a/lib/MC/MCAsmInfoCOFF.cpp
+++ b/lib/MC/MCAsmInfoCOFF.cpp
@@ -19,8 +19,10 @@ void MCAsmInfoCOFF::anchor() { }
 
 MCAsmInfoCOFF::MCAsmInfoCOFF() {
   GlobalPrefix = "_";
-  COMMDirectiveAlignmentIsInBytes = true;
-  LCOMMDirectiveSupportsAlignment = true;
+  // MingW 4.5 and later support .comm with log2 alignment, but .lcomm uses byte
+  // alignment.
+  COMMDirectiveAlignmentIsInBytes = false;
+  LCOMMDirectiveAlignmentType = LCOMM::ByteAlignment;
   HasDotTypeDotSizeDirective = false;
   HasSingleParameterDotFile = false;
   PrivateGlobalPrefix = "L";  // Prefix for private global symbols
diff --git a/lib/MC/MCAsmInfoDarwin.cpp b/lib/MC/MCAsmInfoDarwin.cpp
index 99520d4bf9..a0e3ebad5e 100644
--- a/lib/MC/MCAsmInfoDarwin.cpp
+++ b/lib/MC/MCAsmInfoDarwin.cpp
@@ -32,7 +32,7 @@ MCAsmInfoDarwin::MCAsmInfoDarwin() {
 
   AlignmentIsInBytes = false;
   COMMDirectiveAlignmentIsInBytes = false;
-  LCOMMDirectiveSupportsAlignment = true;
+  LCOMMDirectiveAlignmentType = LCOMM::Log2Alignment;
   InlineAsmStart = " InlineAsm Start";
   InlineAsmEnd = " InlineAsm End";
 
diff --git a/lib/MC/MCAsmStreamer.cpp b/lib/MC/MCAsmStreamer.cpp
index 804e38ead0..b0bc2900ec 100644
--- a/lib/MC/MCAsmStreamer.cpp
+++ b/lib/MC/MCAsmStreamer.cpp
@@ -519,13 +519,16 @@ void MCAsmStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                           unsigned ByteAlign) {
   OS << "\t.lcomm\t" << *Symbol << ',' << Size;
   if (ByteAlign > 1) {
-    assert(MAI.getLCOMMDirectiveSupportsAlignment() &&
-           "alignment not supported on .lcomm!");
-    if (MAI.getCOMMDirectiveAlignmentIsInBytes()) {
+    switch (MAI.getLCOMMDirectiveAlignmentType()) {
+    case LCOMM::NoAlignment:
+      llvm_unreachable("alignment not supported on .lcomm!");
+    case LCOMM::ByteAlignment:
       OS << ',' << ByteAlign;
-    } else {
+      break;
+    case LCOMM::Log2Alignment:
       assert(isPowerOf2_32(ByteAlign) && "alignment must be a power of 2");
       OS << ',' << Log2_32(ByteAlign);
+      break;
     }
   }
   EmitEOL();
diff --git a/lib/MC/MCParser/AsmParser.cpp b/lib/MC/MCParser/AsmParser.cpp
index 271fee02ad..55ef01c796 100644
--- a/lib/MC/MCParser/AsmParser.cpp
+++ b/lib/MC/MCParser/AsmParser.cpp
@@ -2280,11 +2280,13 @@ bool AsmParser::ParseDirectiveComm(bool IsLocal) {
     if (ParseAbsoluteExpression(Pow2Alignment))
       return true;
 
-    if (IsLocal && !Lexer.getMAI().getLCOMMDirectiveSupportsAlignment())
+    LCOMM::LCOMMType LCOMM = Lexer.getMAI().getLCOMMDirectiveAlignmentType();
+    if (IsLocal && LCOMM == LCOMM::NoAlignment)
       return Error(Pow2AlignmentLoc, "alignment not supported on this target");
 
     // If this target takes alignments in bytes (not log) validate and convert.
-    if (Lexer.getMAI().getCOMMDirectiveAlignmentIsInBytes()) {
+    if ((!IsLocal && Lexer.getMAI().getCOMMDirectiveAlignmentIsInBytes()) ||
+        (IsLocal && LCOMM == LCOMM::ByteAlignment)) {
       if (!isPowerOf2_64(Pow2Alignment))
         return Error(Pow2AlignmentLoc, "alignment must be a power of 2");
       Pow2Alignment = Log2_64(Pow2Alignment);
diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonMCAsmInfo.cpp b/lib/Target/Hexagon/MCTargetDesc/HexagonMCAsmInfo.cpp
index ec6b721f12..86f75d1c2d 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonMCAsmInfo.cpp
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonMCAsmInfo.cpp
@@ -24,7 +24,7 @@ HexagonMCAsmInfo::HexagonMCAsmInfo(const Target &T, StringRef TT) {
   HasLEB128 = true;
 
   PrivateGlobalPrefix = ".L";
-  LCOMMDirectiveSupportsAlignment = true;
+  LCOMMDirectiveAlignmentType = LCOMM::ByteAlignment;
   InlineAsmStart = "# InlineAsm Start";
   InlineAsmEnd = "# InlineAsm End";
   ZeroDirective = "\t.space\t";
diff --git a/test/MC/COFF/comm.ll b/test/MC/COFF/comm.ll
new file mode 100644
index 0000000000..74da557fb5
--- /dev/null
+++ b/test/MC/COFF/comm.ll
@@ -0,0 +1,13 @@
+; RUN: llc -mtriple i386-pc-mingw32 < %s | FileCheck %s
+
+@a = internal global i8 0, align 1
+@b = internal global double 0.000000e+00, align 8
+@c = common global i8 0, align 1
+@d = common global double 0.000000e+00, align 8
+
+; .lcomm uses byte alignment
+; CHECK: .lcomm	_a,1
+; CHECK: .lcomm	_b,8,8
+; .comm uses log2 alignment
+; CHECK: .comm	_c,1,0
+; CHECK: .comm	_d,8,3