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Merged
sbc100 merged 1 commit into from
May 7, 2026
Merged

Remove guesswork from getStackPointerGlobal. NFC #8679

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13 changes: 3 additions & 10 deletions src/wasm/wasm-emscripten.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -40,17 +40,10 @@ void addExportedFunction(Module& wasm, Function* function) {
}

Global* getStackPointerGlobal(Module& wasm) {
// Assumption: The stack pointer is either imported as __stack_pointer or
// we just assume it's the first non-imported global.
// TODO(sbc): Find a better way to discover the stack pointer. Perhaps the
// linker could export it by name?
// Assumption: The stack pointer is either be an imported global called
// __stack_pointer or a defined global with that name.
for (auto& g : wasm.globals) {
if (g->imported() && g->base == STACK_POINTER) {
return g.get();
}
}
for (auto& g : wasm.globals) {
if (!g->imported()) {
if (g->base == STACK_POINTER || g->name == STACK_POINTER) {
return g.get();
}
}
Expand Down
14 changes: 7 additions & 7 deletions test/finalize/recursive_safe_stack.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
(memory $0 2)
(data (i32.const 568) "%d:%d\n\00Result: %d\n\00")
(table $0 1 1 funcref)
(global $global$0 (mut i32) (i32.const 66128))
(global $__stack_pointer (mut i32) (i32.const 66128))
(global $global$1 i32 (i32.const 66128))
(global $global$2 i32 (i32.const 587))
(export "memory" (memory $0))
Expand All @@ -18,10 +18,10 @@
)
(func $foo (; 2 ;) (type $0) (param $0 i32) (param $1 i32) (result i32)
(local $2 i32)
(global.set $global$0
(global.set $__stack_pointer
(local.tee $2
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -40,7 +40,7 @@
(local.get $2)
)
)
(global.set $global$0
(global.set $__stack_pointer
(i32.add
(local.get $2)
(i32.const 16)
Expand All @@ -53,10 +53,10 @@
)
(func $__original_main (; 3 ;) (type $2) (result i32)
(local $0 i32)
(global.set $global$0
(global.set $__stack_pointer
(local.tee $0
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -74,7 +74,7 @@
(local.get $0)
)
)
(global.set $global$0
(global.set $__stack_pointer
(i32.add
(local.get $0)
(i32.const 16)
Expand Down
14 changes: 7 additions & 7 deletions test/finalize/recursive_safe_stack.wat.out
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
(type $4 (func (param i32 i32)))
(import "env" "printf" (func $printf (param i32 i32) (result i32)))
(import "env" "__handle_stack_overflow" (func $__handle_stack_overflow (param i32)))
(global $global$0 (mut i32) (i32.const 66128))
(global $__stack_pointer (mut i32) (i32.const 66128))
(global $global$1 i32 (i32.const 66128))
(global $global$2 i32 (i32.const 587))
(global $__stack_base (mut i32) (i32.const 0))
Expand All @@ -33,7 +33,7 @@
(local.tee $3
(local.tee $2
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -51,7 +51,7 @@
)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $3)
)
)
Expand Down Expand Up @@ -92,7 +92,7 @@
)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $4)
)
)
Expand All @@ -112,7 +112,7 @@
(local.tee $1
(local.tee $0
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -130,7 +130,7 @@
)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $1)
)
)
Expand Down Expand Up @@ -170,7 +170,7 @@
)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $2)
)
)
Expand Down
14 changes: 7 additions & 7 deletions test/finalize/safe_stack_standalone-wasm.wat
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@
(memory $0 2)
(data (i32.const 568) "%d:%d\n\00Result: %d\n\00")
(table $0 1 1 funcref)
(global $global$0 (mut i32) (i32.const 66128))
(global $__stack_pointer (mut i32) (i32.const 66128))
(global $global$1 i32 (i32.const 66128))
(global $global$2 i32 (i32.const 587))
(export "memory" (memory $0))
Expand All @@ -18,10 +18,10 @@
)
(func $foo (; 2 ;) (type $0) (param $0 i32) (param $1 i32) (result i32)
(local $2 i32)
(global.set $global$0
(global.set $__stack_pointer
(local.tee $2
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -40,7 +40,7 @@
(local.get $2)
)
)
(global.set $global$0
(global.set $__stack_pointer
(i32.add
(local.get $2)
(i32.const 16)
Expand All @@ -53,10 +53,10 @@
)
(func $__original_main (; 3 ;) (type $2) (result i32)
(local $0 i32)
(global.set $global$0
(global.set $__stack_pointer
(local.tee $0
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -74,7 +74,7 @@
(local.get $0)
)
)
(global.set $global$0
(global.set $__stack_pointer
(i32.add
(local.get $0)
(i32.const 16)
Expand Down
14 changes: 7 additions & 7 deletions test/finalize/safe_stack_standalone-wasm.wat.out
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Original file line number Diff line number Diff line change
Expand Up @@ -4,7 +4,7 @@
(type $2 (func (result i32)))
(type $3 (func (param i32 i32)))
(import "env" "printf" (func $printf (param i32 i32) (result i32)))
(global $global$0 (mut i32) (i32.const 66128))
(global $__stack_pointer (mut i32) (i32.const 66128))
(global $global$1 i32 (i32.const 66128))
(global $global$2 i32 (i32.const 587))
(global $__stack_base (mut i32) (i32.const 0))
Expand All @@ -31,7 +31,7 @@
(local.tee $3
(local.tee $2
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -47,7 +47,7 @@
(unreachable)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $3)
)
)
Expand Down Expand Up @@ -86,7 +86,7 @@
(unreachable)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $4)
)
)
Expand All @@ -106,7 +106,7 @@
(local.tee $1
(local.tee $0
(i32.sub
(global.get $global$0)
(global.get $__stack_pointer)
(i32.const 16)
)
)
Expand All @@ -122,7 +122,7 @@
(unreachable)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $1)
)
)
Expand Down Expand Up @@ -160,7 +160,7 @@
(unreachable)
)
)
(global.set $global$0
(global.set $__stack_pointer
(local.get $2)
)
)
Expand Down
16 changes: 8 additions & 8 deletions test/lit/passes/stack-check-memory64.wast
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Original file line number Diff line number Diff line change
Expand Up @@ -9,8 +9,8 @@

;; CHECK: (type $1 (func (param i64 i64)))

;; CHECK: (global $sp (mut i64) (i64.const 0))
(global $sp (mut i64) (i64.const 0))
;; CHECK: (global $__stack_pointer (mut i64) (i64.const 0))
(global $__stack_pointer (mut i64) (i64.const 0))
;; CHECK: (global $__stack_base (mut i64) (i64.const 0))

;; CHECK: (global $__stack_limit (mut i64) (i64.const 0))
Expand Down Expand Up @@ -41,15 +41,15 @@
;; CHECK-NEXT: (unreachable)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (global.set $sp
;; CHECK-NEXT: (global.set $__stack_pointer
;; CHECK-NEXT: (local.get $0)
;; CHECK-NEXT: )
;; CHECK-NEXT: )
;; CHECK-NEXT: (global.get $sp)
;; CHECK-NEXT: (global.get $__stack_pointer)
;; CHECK-NEXT: )
(func $use_stack (export "use_stack") (result i64)
(global.set $sp (i64.const 42))
(global.get $sp)
(global.set $__stack_pointer (i64.const 42))
(global.get $__stack_pointer)
)
)
;; CHECK: (func $__set_stack_limits (param $0 i64) (param $1 i64)
Expand All @@ -67,8 +67,8 @@

;; CHECK: (type $1 (func (param i64 i64)))

;; CHECK: (global $sp (mut i64) (i64.const 0))
(global $sp (mut i64) (i64.const 0))
;; CHECK: (global $__stack_pointer (mut i64) (i64.const 0))
(global $__stack_pointer (mut i64) (i64.const 0))
;; CHECK: (global $__stack_base (mut i64) (i64.const 0))
(global $__stack_base (mut i64) (i64.const 0))
;; CHECK: (global $__stack_limit (mut i64) (i64.const 0))
Expand Down
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