[WebAssembly] Cleanup of the way globals and global flags are handled

Differential Revision: https://reviews.llvm.org/D44030

llvm-svn: 338894

8 files changed, 35 insertions, 16 deletions

diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyFixupKinds.h b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyFixupKinds.h
index b0af63c924b..23d0de15ea9 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyFixupKinds.h
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyFixupKinds.h
@@ -19,8 +19,6 @@ enum Fixups {
   fixup_code_sleb128_i64,                             // 64-bit signed
   fixup_code_uleb128_i32,                             // 32-bit unsigned
 
-  fixup_code_global_index,                            // 32-bit unsigned
-
   // Marker
   LastTargetFixupKind,
   NumTargetFixupKinds = LastTargetFixupKind - FirstTargetFixupKind
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
index 94ca94e1e18..417912604e0 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCCodeEmitter.cpp
@@ -138,7 +138,7 @@ void WebAssemblyMCCodeEmitter::encodeInstruction(
                  Info.OperandType == WebAssembly::OPERAND_TYPEINDEX) {
         FixupKind = MCFixupKind(WebAssembly::fixup_code_uleb128_i32);
       } else if (Info.OperandType == WebAssembly::OPERAND_GLOBAL) {
-        FixupKind = MCFixupKind(WebAssembly::fixup_code_global_index);
+        FixupKind = MCFixupKind(WebAssembly::fixup_code_uleb128_i32);
       } else {
         llvm_unreachable("unexpected symbolic operand kind");
       }
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
index 62a59317165..071e4586856 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h
@@ -81,6 +81,16 @@ enum {
   // whether the value represents a control-flow label.
   VariableOpImmediateIsLabel = (1 << 1)
 };
+
+/// Target Operand Flag enum.
+enum TOF {
+  MO_NO_FLAG = 0,
+
+  // Flags to indicate the type of the symbol being referenced
+  MO_SYMBOL_FUNCTION = 0x1,
+  MO_SYMBOL_GLOBAL   = 0x2,
+  MO_SYMBOL_MASK     = 0x3,
+};
 } // end namespace WebAssemblyII
 
 } // end namespace llvm
diff --git a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
index 4fb12d40b01..dc876ab585b 100644
--- a/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
+++ b/llvm/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyWasmObjectWriter.cpp
@@ -81,6 +81,11 @@ static const MCSection *GetFixupSection(const MCExpr *Expr) {
   return nullptr;
 }
 
+static bool IsGlobalType(const MCValue &Target) {
+  const MCSymbolRefExpr *RefA = Target.getSymA();
+  return RefA && RefA->getKind() == MCSymbolRefExpr::VK_WebAssembly_GLOBAL;
+}
+
 unsigned
 WebAssemblyWasmObjectWriter::getRelocType(const MCValue &Target,
                                           const MCFixup &Fixup) const {
@@ -89,8 +94,6 @@ WebAssemblyWasmObjectWriter::getRelocType(const MCValue &Target,
   bool IsFunction = IsFunctionExpr(Fixup.getValue());
 
   switch (unsigned(Fixup.getKind())) {
-  case WebAssembly::fixup_code_global_index:
-    return wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB;
   case WebAssembly::fixup_code_sleb128_i32:
     if (IsFunction)
       return wasm::R_WEBASSEMBLY_TABLE_INDEX_SLEB;
@@ -98,6 +101,8 @@ WebAssemblyWasmObjectWriter::getRelocType(const MCValue &Target,
   case WebAssembly::fixup_code_sleb128_i64:
     llvm_unreachable("fixup_sleb128_i64 not implemented yet");
   case WebAssembly::fixup_code_uleb128_i32:
+    if (IsGlobalType(Target))
+      return wasm::R_WEBASSEMBLY_GLOBAL_INDEX_LEB;
     if (IsFunctionType(Target))
       return wasm::R_WEBASSEMBLY_TYPE_INDEX_LEB;
     if (IsFunction)
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
index 052c94e9d6a..0835ff38a13 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyFrameLowering.cpp
@@ -107,7 +107,7 @@ static void writeSPToMemory(unsigned SrcReg, MachineFunction &MF,
   const char *ES = "__stack_pointer";
   auto *SPSymbol = MF.createExternalSymbolName(ES);
   BuildMI(MBB, InsertStore, DL, TII->get(WebAssembly::SET_GLOBAL_I32))
-      .addExternalSymbol(SPSymbol)
+      .addExternalSymbol(SPSymbol, WebAssemblyII::MO_SYMBOL_GLOBAL)
       .addReg(SrcReg);
 }
 
@@ -153,7 +153,7 @@ void WebAssemblyFrameLowering::emitPrologue(MachineFunction &MF,
   const char *ES = "__stack_pointer";
   auto *SPSymbol = MF.createExternalSymbolName(ES);
   BuildMI(MBB, InsertPt, DL, TII->get(WebAssembly::GET_GLOBAL_I32), SPReg)
-      .addExternalSymbol(SPSymbol);
+      .addExternalSymbol(SPSymbol, WebAssemblyII::MO_SYMBOL_GLOBAL);
 
   bool HasBP = hasBP(MF);
   if (HasBP) {
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 95502762a78..aa3c0d03913 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -871,7 +871,7 @@ SDValue WebAssemblyTargetLowering::LowerExternalSymbol(
   // functions.
   return DAG.getNode(WebAssemblyISD::Wrapper, DL, VT,
                      DAG.getTargetExternalSymbol(ES->getSymbol(), VT,
-                                                 /*TargetFlags=*/0x1));
+                                                 WebAssemblyII::MO_SYMBOL_FUNCTION));
 }
 
 SDValue WebAssemblyTargetLowering::LowerJumpTable(SDValue Op,
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
index d85db14fc67..5a9e3c67176 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.cpp
@@ -108,9 +108,11 @@ MCSymbol *WebAssemblyMCInstLower::GetExternalSymbolSymbol(
 
 MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(MCSymbol *Sym,
                                                      int64_t Offset,
-                                                     bool IsFunc) const {
+                                                     bool IsFunc,
+                                                     bool IsGlob) const {
   MCSymbolRefExpr::VariantKind VK =
-      IsFunc ? MCSymbolRefExpr::VK_WebAssembly_FUNCTION
+      IsFunc ? MCSymbolRefExpr::VK_WebAssembly_FUNCTION :
+      IsGlob ? MCSymbolRefExpr::VK_WebAssembly_GLOBAL
              : MCSymbolRefExpr::VK_None;
 
   const MCExpr *Expr = MCSymbolRefExpr::create(Sym, VK, Ctx);
@@ -118,6 +120,8 @@ MCOperand WebAssemblyMCInstLower::LowerSymbolOperand(MCSymbol *Sym,
   if (Offset != 0) {
     if (IsFunc)
       report_fatal_error("Function addresses with offsets not supported");
+    if (IsGlob)
+      report_fatal_error("Global indexes with offsets not supported");
     Expr =
         MCBinaryExpr::createAdd(Expr, MCConstantExpr::create(Offset, Ctx), Ctx);
   }
@@ -212,18 +216,20 @@ void WebAssemblyMCInstLower::Lower(const MachineInstr *MI,
       break;
     }
     case MachineOperand::MO_GlobalAddress:
-      assert(MO.getTargetFlags() == 0 &&
+      assert(MO.getTargetFlags() == WebAssemblyII::MO_NO_FLAG &&
              "WebAssembly does not use target flags on GlobalAddresses");
       MCOp = LowerSymbolOperand(GetGlobalAddressSymbol(MO), MO.getOffset(),
-                                MO.getGlobal()->getValueType()->isFunctionTy());
+                                MO.getGlobal()->getValueType()->isFunctionTy(),
+                                false);
       break;
     case MachineOperand::MO_ExternalSymbol:
       // The target flag indicates whether this is a symbol for a
       // variable or a function.
-      assert((MO.getTargetFlags() & -2) == 0 &&
-             "WebAssembly uses only one target flag bit on ExternalSymbols");
+      assert((MO.getTargetFlags() & ~WebAssemblyII::MO_SYMBOL_MASK) == 0 &&
+             "WebAssembly uses only symbol flags on ExternalSymbols");
       MCOp = LowerSymbolOperand(GetExternalSymbolSymbol(MO), /*Offset=*/0,
-                                MO.getTargetFlags() & 1);
+          (MO.getTargetFlags() & WebAssemblyII::MO_SYMBOL_FUNCTION) != 0,
+          (MO.getTargetFlags() & WebAssemblyII::MO_SYMBOL_GLOBAL) != 0);
       break;
     }
 
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.h b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.h
index 41b4313bb38..3a9d52b1c8c 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.h
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyMCInstLower.h
@@ -34,7 +34,7 @@ class LLVM_LIBRARY_VISIBILITY WebAssemblyMCInstLower {
   MCSymbol *GetGlobalAddressSymbol(const MachineOperand &MO) const;
   MCSymbol *GetExternalSymbolSymbol(const MachineOperand &MO) const;
   MCOperand LowerSymbolOperand(MCSymbol *Sym, int64_t Offset,
-                               bool IsFunc) const;
+                               bool IsFunc, bool IsGlob) const;
 
 public:
   WebAssemblyMCInstLower(MCContext &ctx, WebAssemblyAsmPrinter &printer)