Index: test/wasm/alias.ll
===================================================================
--- test/wasm/alias.ll
+++ test/wasm/alias.ll
@@ -42,6 +42,12 @@
 ; CHECK-NEXT:         InitExpr:        
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66560
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:        
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66560
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:         
 ; CHECK-NEXT:       - Name:            memory
@@ -53,6 +59,9 @@
 ; CHECK-NEXT:       - Name:            start_alias
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           0
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Functions:       
 ; CHECK-NEXT:       - Index:           0
Index: test/wasm/call-indirect.ll
===================================================================
--- test/wasm/call-indirect.ll
+++ test/wasm/call-indirect.ll
@@ -71,6 +71,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66576
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66576
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -91,6 +97,9 @@
 ; CHECK-NEXT:       - Name:            call_ptr
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           4
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            ELEM
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - Offset:
Index: test/wasm/comdats.ll
===================================================================
--- test/wasm/comdats.ll
+++ test/wasm/comdats.ll
@@ -20,6 +20,12 @@
 ; CHECK-NEXT:        InitExpr:
 ; CHECK-NEXT:          Opcode:          I32_CONST
 ; CHECK-NEXT:          Value:           66576
+; CHECK-NEXT:      - Index:           1
+; CHECK-NEXT:        Type:            I32
+; CHECK-NEXT:        Mutable:         false
+; CHECK-NEXT:        InitExpr:
+; CHECK-NEXT:          Opcode:          I32_CONST
+; CHECK-NEXT:          Value:           66576
 ; CHECK-NEXT:  - Type:            EXPORT
 ; CHECK-NEXT:    Exports:
 ; CHECK-NEXT:      - Name:            memory
@@ -37,6 +43,9 @@
 ; CHECK-NEXT:      - Name:            callInline2
 ; CHECK-NEXT:        Kind:            FUNCTION
 ; CHECK-NEXT:        Index:           3
+; CHECK-NEXT:      - Name:            __heap_base
+; CHECK-NEXT:        Kind:            GLOBAL
+; CHECK-NEXT:        Index:           1
 ; CHECK-NEXT:  - Type:            ELEM
 ; CHECK-NEXT:    Segments:
 ; CHECK-NEXT:      - Offset:
Index: test/wasm/data-layout.ll
===================================================================
--- test/wasm/data-layout.ll
+++ test/wasm/data-layout.ll
@@ -22,30 +22,36 @@
 ; CHECK-NEXT:         Mutable:         false
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           1024
+; CHECK-NEXT:           Value:           66608
 ; CHECK-NEXT:       - Index:           2
 ; CHECK-NEXT:         Type:            I32
 ; CHECK-NEXT:         Mutable:         false
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           1040
+; CHECK-NEXT:           Value:           1024
 ; CHECK-NEXT:       - Index:           3
 ; CHECK-NEXT:         Type:            I32
 ; CHECK-NEXT:         Mutable:         false
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
-; CHECK-NEXT:           Value:           1048
+; CHECK-NEXT:           Value:           1040
 ; CHECK-NEXT:       - Index:           4
 ; CHECK-NEXT:         Type:            I32
 ; CHECK-NEXT:         Mutable:         false
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           1048
+; CHECK-NEXT:       - Index:           5
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           1052
 
 ; CHECK:       - Type:            DATA
 ; CHECK-NEXT:     Relocations:
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_MEMORY_ADDR_I32
-; CHECK-NEXT:         Index:           4
+; CHECK-NEXT:         Index:           5
 ; CHECK-NEXT:         Offset:          0x0000001F
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - SectionOffset:   7
Index: test/wasm/export.ll
===================================================================
--- test/wasm/export.ll
+++ test/wasm/export.ll
@@ -26,4 +26,7 @@
 ; CHECK-NEXT:       - Name:            hidden_function
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           0
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            CODE
Index: test/wasm/load-undefined.ll
===================================================================
--- test/wasm/load-undefined.ll
+++ test/wasm/load-undefined.ll
@@ -27,6 +27,9 @@
 ; CHECK-NEXT:       - Name:            ret64
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           2
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:
 
 
Index: test/wasm/local-symbols.ll
===================================================================
--- test/wasm/local-symbols.ll
+++ test/wasm/local-symbols.ll
@@ -47,6 +47,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66576
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66576
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -55,6 +61,9 @@
 ; CHECK-NEXT:       - Name:            _start
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Functions:
 ; CHECK-NEXT:       - Index:           0
Index: test/wasm/stack-pointer.ll
===================================================================
--- test/wasm/stack-pointer.ll
+++ test/wasm/stack-pointer.ll
@@ -41,6 +41,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66560
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66560
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -52,6 +58,9 @@
 ; CHECK-NEXT:       - Name:            __wasm_call_ctors
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Relocations:
 ; CHECK-NEXT:       - Type:            R_WEBASSEMBLY_GLOBAL_INDEX_LEB
Index: test/wasm/visibility-hidden.ll
===================================================================
--- test/wasm/visibility-hidden.ll
+++ test/wasm/visibility-hidden.ll
@@ -43,4 +43,7 @@
 ; CHECK-NEXT:       - Name:            objectDefault
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:
Index: test/wasm/weak-alias-overide.ll
===================================================================
--- test/wasm/weak-alias-overide.ll
+++ test/wasm/weak-alias-overide.ll
@@ -49,6 +49,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66560
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66560
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -75,6 +81,9 @@
 ; CHECK-NEXT:       - Name:            call_direct_ptr
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           6
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            ELEM
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - Offset:          
Index: test/wasm/weak-alias.ll
===================================================================
--- test/wasm/weak-alias.ll
+++ test/wasm/weak-alias.ll
@@ -46,6 +46,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66560
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66560
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -72,6 +78,9 @@
 ; CHECK-NEXT:       - Name:            call_direct_ptr
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           5
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            ELEM
 ; CHECK-NEXT:     Segments:        
 ; CHECK-NEXT:       - Offset:          
Index: test/wasm/weak-symbols.ll
===================================================================
--- test/wasm/weak-symbols.ll
+++ test/wasm/weak-symbols.ll
@@ -46,6 +46,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66576
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66576
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -63,6 +69,9 @@
 ; CHECK-NEXT:       - Name:            exportWeak2
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           4
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            ELEM
 ; CHECK-NEXT:     Segments:
 ; CHECK-NEXT:       - Offset:
Index: test/wasm/weak-undefined.ll
===================================================================
--- test/wasm/weak-undefined.ll
+++ test/wasm/weak-undefined.ll
@@ -56,6 +56,12 @@
 ; CHECK-NEXT:         InitExpr:
 ; CHECK-NEXT:           Opcode:          I32_CONST
 ; CHECK-NEXT:           Value:           66560
+; CHECK-NEXT:       - Index:           1
+; CHECK-NEXT:         Type:            I32
+; CHECK-NEXT:         Mutable:         false
+; CHECK-NEXT:         InitExpr:
+; CHECK-NEXT:           Opcode:          I32_CONST
+; CHECK-NEXT:           Value:           66560
 ; CHECK-NEXT:   - Type:            EXPORT
 ; CHECK-NEXT:     Exports:
 ; CHECK-NEXT:       - Name:            memory
@@ -70,6 +76,9 @@
 ; CHECK-NEXT:       - Name:            get_address_of_global_var
 ; CHECK-NEXT:         Kind:            FUNCTION
 ; CHECK-NEXT:         Index:           1
+; CHECK-NEXT:       - Name:            __heap_base
+; CHECK-NEXT:         Kind:            GLOBAL
+; CHECK-NEXT:         Index:           1
 ; CHECK-NEXT:   - Type:            CODE
 ; CHECK-NEXT:     Functions:
 ; CHECK-NEXT:       - Index:           0
Index: wasm/Config.h
===================================================================
--- wasm/Config.h
+++ wasm/Config.h
@@ -40,6 +40,7 @@
   llvm::StringSet<> AllowUndefinedSymbols;
   std::vector<llvm::StringRef> SearchPaths;
   Symbol *StackPointerSymbol = nullptr;
+  Symbol *HeapBaseSymbol = nullptr;
   Symbol *CtorSymbol = nullptr;
 };
 
Index: wasm/Driver.cpp
===================================================================
--- wasm/Driver.cpp
+++ wasm/Driver.cpp
@@ -310,6 +310,7 @@
     Config->CtorSymbol = Symtab->addDefinedFunction(
         "__wasm_call_ctors", &Signature, WASM_SYMBOL_VISIBILITY_HIDDEN);
     Config->StackPointerSymbol = Symtab->addDefinedGlobal("__stack_pointer");
+    Config->HeapBaseSymbol = Symtab->addDefinedGlobal("__heap_base");
     Symtab->addDefinedGlobal("__dso_handle")->setVirtualAddress(0);
   }
 
Index: wasm/Writer.cpp
===================================================================
--- wasm/Writer.cpp
+++ wasm/Writer.cpp
@@ -572,6 +572,11 @@
     MemoryPtr += Config->ZStackSize;
     Config->StackPointerSymbol->setVirtualAddress(MemoryPtr);
     debugPrint("mem: stack top   = %d\n", MemoryPtr);
+    // Set `__heap_base` to directly follow the end of the stack.  We don't
+    // allocate any heap memory up front, but instead really on the malloc/brk
+    // implementation growing the memory at runtime.
+    Config->HeapBaseSymbol->setVirtualAddress(MemoryPtr);
+    debugPrint("mem: heap base   = %d\n", MemoryPtr);
   }
 
   uint32_t MemSize = alignTo(MemoryPtr, WasmPageSize);
@@ -669,6 +674,11 @@
     Config->StackPointerSymbol->setOutputIndex(GlobalIndex++);
   }
 
+  if (Config->HeapBaseSymbol) {
+    DefinedGlobals.emplace_back(Config->HeapBaseSymbol);
+    Config->HeapBaseSymbol->setOutputIndex(GlobalIndex++);
+  }
+
   if (Config->EmitRelocs)
     DefinedGlobals.reserve(Symtab->getSymbols().size());