; memory. In this case the --stack-first option is being passed along with a
; stack size of 512. This means (since the stack grows down) the stack pointer
; global should be initialized to 512.
+; Also test that __heap_base is still aligned with the --stack-first option.
-RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/start.s -o %t.o
-RUN: wasm-ld -z stack-size=512 --stack-first --export=__data_end --export=__heap_base -o %t.wasm %t.o
+RUN: llvm-mc -filetype=obj -triple=wasm32-unknown-unknown %p/Inputs/stack-first.s -o %t.o
+RUN: wasm-ld -z stack-size=512 --stack-first --export=__data_end --export=__heap_base --export=someByte -o %t.wasm %t.o
RUN: obj2yaml %t.wasm | FileCheck %s
CHECK: - Type: GLOBAL
CHECK-NEXT: Mutable: false
CHECK-NEXT: InitExpr:
CHECK-NEXT: Opcode: I32_CONST
-CHECK-NEXT: Value: 512
+CHECK-NEXT: Value: 513
+CHECK-NEXT: - Index: 3
+CHECK-NEXT: Type: I32
+CHECK-NEXT: Mutable: false
+CHECK-NEXT: InitExpr:
+CHECK-NEXT: Opcode: I32_CONST
+CHECK-NEXT: Value: 528
CHECK-NEXT: - Type: EXPORT
CHECK-NEXT: Exports:
CHECK-NEXT: - Name: memory
CHECK-NEXT: - Name: _start
CHECK-NEXT: Kind: FUNCTION
CHECK-NEXT: Index: 0
-CHECK-NEXT: - Name: __data_end
+CHECK-NEXT: - Name: someByte
CHECK-NEXT: Kind: GLOBAL
CHECK-NEXT: Index: 1
-CHECK-NEXT: - Name: __heap_base
+CHECK-NEXT: - Name: __data_end
CHECK-NEXT: Kind: GLOBAL
CHECK-NEXT: Index: 2
+CHECK-NEXT: - Name: __heap_base
+CHECK-NEXT: Kind: GLOBAL
+CHECK-NEXT: Index: 3
namespace lld {
namespace wasm {
static constexpr int stackAlignment = 16;
+static constexpr int heapAlignment = 16;
namespace {
placeStack();
if (WasmSym::heapBase) {
- // Set `__heap_base` to directly follow the end of the stack or global data.
- // The fact that this comes last means that a malloc/brk implementation
- // can grow the heap at runtime.
+ // Set `__heap_base` to follow the end of the stack or global data. The
+ // fact that this comes last means that a malloc/brk implementation can
+ // grow the heap at runtime.
+ // We'll align the heap base here because memory allocators might expect
+ // __heap_base to be aligned already.
+ memoryPtr = alignTo(memoryPtr, heapAlignment);
log("mem: heap base = " + Twine(memoryPtr));
WasmSym::heapBase->setVA(memoryPtr);
}