Implement ordinary function inlining and subsume Whamm probe inlining

src/engine/x86-64/X86_64SinglePassCompiler.v3

@@ -1535,7 +1535,8 @@ component X86_64Spc {
 		return addr;
 	}
 	def estimateCodeSizeFor(decl: FuncDecl) -> int {
-		return 60 + decl.orig_bytecode.length * 20; // TODO: huge overestimate
+		// TODO: very imprecise estimate
+		return 60 + decl.orig_bytecode.length * 20 * (4 << byte.view(SpcTuning.maxInlineDepth));
 	}
 	private def lazyCompile(wf: WasmFunction) -> (WasmFunction, Pointer, Throwable) {
 		// The global stub simply consults the execution strategy.

src/util/Whamm.v3

@@ -175,10 +175,9 @@ component Whamm {
 class WhammProbe(func: Function, sig: Array<WhammArg>) extends Probe {
 	var trampoline: TargetCode;
 	// properties set by the spc to make inlining optimization decisions.
-	var inline_heuristic_checked = false;
-	var spc_inline_func = false;
-	var spc_swap_instance = false;
-	var spc_swap_membase = false;
+	var swap_checked = false;
+	var swap_instance = false;
+	var swap_membase = false;
 
 	private def args = if(sig.length == 0, Values.NONE, Array<Value>.new(sig.length));
 
@@ -203,6 +202,31 @@ class WhammProbe(func: Function, sig: Array<WhammArg>) extends Probe {
 		}
 		return ProbeAction.Continue;
 	}
+
+	// If function is to be inlined, check to see if instance or mem0_base need to be swapped.
+	def checkSwap() {
+		if (swap_checked) return;
+		var bi = BytecodeIterator.new().reset(WasmFunction.!(func).decl);
+		while (bi.more()) {
+			var op = bi.current();
+			match (op) {
+				// These opcodes require swapping the instance.
+				THROW, CALL, CALL_INDIRECT, MEMORY_INIT, MEMORY_SIZE, MEMORY_GROW, MEMORY_COPY, MEMORY_FILL, REF_FUNC, DATA_DROP,
+				ELEM_DROP, TABLE_INIT, TABLE_SIZE, TABLE_COPY, TABLE_GROW, GLOBAL_SET, GLOBAL_GET, TABLE_SET, TABLE_GET => swap_instance = true;
+				// Load/store opcodes require either the memory base or the instance.
+				I32_STORE, I64_STORE, F32_STORE, F64_STORE, I32_STORE8, I32_STORE16, I64_STORE8, I64_STORE16, I64_STORE32,
+				V128_STORE, I32_LOAD, I64_LOAD, F32_LOAD, F64_LOAD, I32_LOAD8_S, I32_LOAD8_U, I32_LOAD16_S, I32_LOAD16_U,
+				I64_LOAD8_S, I64_LOAD8_U, I64_LOAD16_S, I64_LOAD16_U, I64_LOAD32_S, I64_LOAD32_U, V128_LOAD => {
+					var memarg = bi.immptr().read_MemArg();
+					if (memarg.memory_index == 0) swap_membase = true;
+					else swap_instance = true;
+				}
+				_ => ;
+			}
+			bi.next();
+		}
+		swap_checked = true;
+	}
 }
 
 def parseParam0(r: TextReader) -> WhammParam {

test/inline/failures.x86-64-linux.dyn

@@ -1,4 +1,5 @@
 inline_test_arithmetic.wasm
 inline_test_locals_control.wasm
 inline_test_nesting.wasm
+inline_test_return.wasm
 

test/inline/inline_test_return.wasm.exit

@@ -0,0 +1 @@
+0

test/inline/inline_test_return.wasm.flags

@@ -0,0 +1 @@
+--metrics=spc*calls --inline-max-depth=1

test/inline/inline_test_return.wasm.out

@@ -0,0 +1,4 @@
+spc:static_calls         : 6         calls
+spc:static_inlined_calls : 6         calls
+spc:dynamic_calls        : 6         calls
+spc:dynamic_inlined_calls : 6        calls

test/inline/inline_test_return.wat

@@ -0,0 +1,97 @@
+;; Test inlined functions with explicit RETURN, including nested control flow
+;; and paths where extra values are on the stack at the time of return.
+(module
+  ;; Two levels of nested ifs; in the early-return path, 2*a is an extra value
+  ;; on the value stack below the returned a+b.
+  (func $weighted (param i32) (param i32) (result i32)
+    block (result i32)
+      local.get 0
+      i32.const 2
+      i32.mul           ;; [2a] -- extra below when early return fires
+      block
+        local.get 0
+        i32.const 0
+        i32.gt_s
+        if
+          local.get 1
+          i32.const 0
+          i32.gt_s
+          if
+            ;; both positive: return a+b; 2a is extra on stack
+            local.get 0
+            local.get 1
+            i32.add
+            return
+          end
+        end
+      end
+      local.get 1
+      i32.add           ;; fallthrough: 2a+b
+    end
+  )
+
+  ;; Clamp x to [lo, hi]; two levels of nesting, returns on multiple paths.
+  (func $clamp (param i32) (param i32) (param i32) (result i32)
+    local.get 0
+    local.get 1
+    i32.lt_s
+    if
+      local.get 1
+      return
+    end
+    local.get 0
+    local.get 2
+    i32.gt_s
+    if
+      local.get 2
+      return
+    end
+    local.get 0
+  )
+
+  (func (export "main") (result i32)
+    i32.const 3
+    i32.const 4
+    call $weighted
+    i32.const 7         ;; both positive: 3+4=7
+    i32.ne
+
+    i32.const 3
+    i32.const -1
+    call $weighted
+    i32.const 5         ;; b<=0: 2*3+(-1)=5
+    i32.ne
+    i32.or
+
+    i32.const -1
+    i32.const 4
+    call $weighted
+    i32.const 2         ;; a<=0: 2*(-1)+4=2
+    i32.ne
+    i32.or
+
+    i32.const 5
+    i32.const 0
+    i32.const 10
+    call $clamp
+    i32.const 5
+    i32.ne
+    i32.or
+
+    i32.const -3
+    i32.const 0
+    i32.const 10
+    call $clamp
+    i32.const 0
+    i32.ne
+    i32.or
+
+    i32.const 15
+    i32.const 0
+    i32.const 10
+    call $clamp
+    i32.const 10
+    i32.ne
+    i32.or
+  )
+)