Index: llvm/trunk/lib/MC/WasmObjectWriter.cpp
===================================================================
--- llvm/trunk/lib/MC/WasmObjectWriter.cpp
+++ llvm/trunk/lib/MC/WasmObjectWriter.cpp
@@ -38,6 +38,10 @@
 
 namespace {
 
+// Went we ceate the indirect function table we start at 1, so that there is
+// and emtpy slot at 0 and therefore calling a null function pointer will trap.
+static const uint32_t kInitialTableOffset = 1;
+
 // For patching purposes, we need to remember where each section starts, both
 // for patching up the section size field, and for patching up references to
 // locations within the section.
@@ -789,7 +793,7 @@
 
   // init expr for starting offset
   write8(wasm::WASM_OPCODE_I32_CONST);
-  encodeSLEB128(0, getStream());
+  encodeSLEB128(kInitialTableOffset, getStream());
   write8(wasm::WASM_OPCODE_END);
 
   encodeULEB128(TableElems.size(), getStream());
@@ -1326,7 +1330,7 @@
         case wasm::R_WEBASSEMBLY_MEMORY_ADDR_I32:
         case wasm::R_WEBASSEMBLY_MEMORY_ADDR_SLEB: {
           uint32_t Index = SymbolIndices.find(&WS)->second;
-          IndirectSymbolIndices[&WS] = TableElems.size();
+          IndirectSymbolIndices[&WS] = TableElems.size() + kInitialTableOffset;
           DEBUG(dbgs() << "  -> adding to table: " << TableElems.size() << "\n");
           TableElems.push_back(Index);
           registerFunctionType(WS);
Index: llvm/trunk/test/MC/WebAssembly/external-func-address.ll
===================================================================
--- llvm/trunk/test/MC/WebAssembly/external-func-address.ll
+++ llvm/trunk/test/MC/WebAssembly/external-func-address.ll
@@ -29,10 +29,10 @@
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - Offset:
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           0
+; CHECK-NEXT:           Value:           1
 ; CHECK-NEXT:         Functions:       [ 0 ]
 ; CHECK:        - Type:            DATA
 ; CHECK-NEXT:     Relocations:
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_I32
-; CHECK-NEXT:         Index:           0
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:         Offset:          0x00000006
Index: llvm/trunk/test/MC/WebAssembly/func-address.ll
===================================================================
--- llvm/trunk/test/MC/WebAssembly/func-address.ll
+++ llvm/trunk/test/MC/WebAssembly/func-address.ll
@@ -42,6 +42,6 @@
 ; CHECK:     Relocation {
 ; CHECK:       Type: R_WEBASSEMBLY_TABLE_INDEX_SLEB (1)
 ; CHECK:       Offset: 0x1E
-; CHECK:       Index: 0x0
+; CHECK:       Index: 0x1
 ; CHECK:     }
 ; CHECK:   }
Index: llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll
===================================================================
--- llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll
+++ llvm/trunk/test/MC/WebAssembly/global-ctor-dtor.ll
@@ -87,7 +87,7 @@
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - Offset:          
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           0
+; CHECK-NEXT:           Value:           1
 ; CHECK-NEXT:         Functions:       [ 5, 7 ]
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Relocations:     
@@ -95,7 +95,7 @@
 ; CHECK-NEXT:         Index:           0
 ; CHECK-NEXT:         Offset:          0x00000004
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_SLEB
-; CHECK-NEXT:         Index:           0
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:         Offset:          0x0000000F
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_MEMORY_ADDR_SLEB
 ; CHECK-NEXT:         Index:           0
@@ -107,7 +107,7 @@
 ; CHECK-NEXT:         Index:           2
 ; CHECK-NEXT:         Offset:          0x0000002C
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_SLEB
-; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:         Index:           2
 ; CHECK-NEXT:         Offset:          0x00000037
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_MEMORY_ADDR_SLEB
 ; CHECK-NEXT:         Index:           0
@@ -121,13 +121,13 @@
 ; CHECK-NEXT:         Body:            1080808080000B
 ; CHECK-NEXT:       - Index:           6
 ; CHECK-NEXT:         Locals:          
-; CHECK-NEXT:         Body:            024041808080800041004180808080001081808080000D000F0B00000B
+; CHECK-NEXT:         Body:            024041818080800041004180808080001081808080000D000F0B00000B
 ; CHECK-NEXT:       - Index:           7
 ; CHECK-NEXT:         Locals:          
 ; CHECK-NEXT:         Body:            1082808080000B
 ; CHECK-NEXT:       - Index:           8
 ; CHECK-NEXT:         Locals:          
-; CHECK-NEXT:         Body:            024041818080800041004180808080001081808080000D000F0B00000B
+; CHECK-NEXT:         Body:            024041828080800041004180808080001081808080000D000F0B00000B
 ; CHECK-NEXT:   - Type:            DATA
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - SectionOffset:   6
Index: llvm/trunk/test/MC/WebAssembly/weak-alias.ll
===================================================================
--- llvm/trunk/test/MC/WebAssembly/weak-alias.ll
+++ llvm/trunk/test/MC/WebAssembly/weak-alias.ll
@@ -130,7 +130,7 @@
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - Offset:          
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           0
+; CHECK-NEXT:           Value:           1
 ; CHECK-NEXT:         Functions:       [ 1, 0 ]
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Relocations:     
@@ -171,10 +171,10 @@
 ; CHECK-NEXT:   - Type:            DATA
 ; CHECK-NEXT:     Relocations:     
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_I32
-; CHECK-NEXT:         Index:           0
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:         Offset:          0x0000000F
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_TABLE_INDEX_I32
-; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:         Index:           2
 ; CHECK-NEXT:         Offset:          0x00000018
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - SectionOffset:   6
@@ -188,7 +188,7 @@
 ; CHECK-NEXT:         Offset:          
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           8
-; CHECK-NEXT:         Content:         '00000000'
+; CHECK-NEXT:         Content:         '01000000'
 
 ; CHECK:        - Type:            CUSTOM
 ; CHECK-NEXT:     Name:            name