wazeroir: removes allocations in wasmOpcodeSignature asymptotically (#1145)

Signed-off-by: Takeshi Yoneda <takeshi@tetrate.io>

internal/wazeroir/compiler.go

@@ -188,7 +188,8 @@ type compiler struct {
 
 	ensureTermination bool
 	// Pre-allocated bytes.Reader to be used in varous places.
-	br *bytes.Reader
+	br             *bytes.Reader
+	funcTypeToSigs *funcTypeToIRSignatures
 }
 
 //lint:ignore U1000 for debugging only.
@@ -276,10 +277,18 @@ func CompileFunctions(enabledFeatures api.CoreFeatures, callFrameStackSizeInUint
 		tableTypes[i] = tables[i].Type
 	}
 
+	types := module.TypeSection
+
+	funcTypeToSigs := &funcTypeToIRSignatures{
+		indirectCalls: make([]*signature, len(types)),
+		directCalls:   make([]*signature, len(types)),
+		wasmTypes:     types,
+	}
+
 	var ret []*CompilationResult
 	for funcIndex := range module.FunctionSection {
 		typeID := module.FunctionSection[funcIndex]
-		sig := module.TypeSection[typeID]
+		sig := types[typeID]
 		code := module.CodeSection[funcIndex]
 		if code.GoFunc != nil {
 			// Assume the function might use memory if it has a parameter for the api.Module
@@ -300,8 +309,8 @@ func CompileFunctions(enabledFeatures api.CoreFeatures, callFrameStackSizeInUint
 			continue
 		}
 		r, err := compile(enabledFeatures, callFrameStackSizeInUint64, sig, code.Body,
-			code.LocalTypes, module.TypeSection, functions, globals, code.BodyOffsetInCodeSection,
-			module.DWARFLines != nil, ensureTermination)
+			code.LocalTypes, types, functions, globals, code.BodyOffsetInCodeSection,
+			module.DWARFLines != nil, ensureTermination, funcTypeToSigs)
 		if err != nil {
 			def := module.FunctionDefinitionSection[uint32(funcIndex)+module.ImportFuncCount()]
 			return nil, fmt.Errorf("failed to lower func[%s] to wazeroir: %w", def.DebugName(), err)
@@ -309,7 +318,7 @@ func CompileFunctions(enabledFeatures api.CoreFeatures, callFrameStackSizeInUint
 		r.IsHostFunction = code.IsHostFunction
 		r.Globals = globals
 		r.Functions = functions
-		r.Types = module.TypeSection
+		r.Types = types
 		r.HasMemory = hasMemory
 		r.HasTable = hasTable
 		r.HasDataInstances = hasDataInstances
@@ -335,6 +344,7 @@ func compile(enabledFeatures api.CoreFeatures,
 	bodyOffsetInCodeSection uint64,
 	needSourceOffset bool,
 	ensureTermination bool,
+	funcTypeToSigs *funcTypeToIRSignatures,
 ) (*CompilationResult, error) {
 	c := compiler{
 		enabledFeatures:            enabledFeatures,
@@ -351,6 +361,7 @@ func compile(enabledFeatures api.CoreFeatures,
 		bodyOffsetInCodeSection:    bodyOffsetInCodeSection,
 		ensureTermination:          ensureTermination,
 		br:                         bytes.NewReader(nil),
+		funcTypeToSigs:             funcTypeToSigs,
 	}
 
 	c.initializeStack()