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compiler: merge runtime.typecodeID and runtime.typeInInterface

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This distinction was useful before when reflect wasn't properly
supported. Back then it made sense to only include method sets that were
actually used in an interface. But now that it is possible to get to
other values (for example, by extracting fields from structs) and it is
possible to turn them back into interfaces, it is necessary to preserve
all method sets that can possibly be used in the program in a type
assert, interface assert or interface method call.

In the future, this logic will need to be revisited again when
reflect.New or reflect.Zero gets implemented.

Code size increases a bit in some cases, but usually in a very limited
way (except for one outlier in the drivers smoke tests). The next commit
will improve the situation significantly.
This commit is contained in:
Ayke van Laethem
2021-03-15 23:53:05 +01:00
committed by Ron Evans
parent aa7c7b7bd9
commit bbb2909283
11 changed files with 122 additions and 104 deletions
Download Patch File Download Diff File Expand all files Collapse all files
transform/interface-lowering.go
+71 -54
View File
@@ -46,6 +46,7 @@ import (
// any method in particular.
type signatureInfo struct {
name string
global llvm.Value
methods []*methodInfo
interfaces []*interfaceInfo
}
@@ -73,13 +74,12 @@ type methodInfo struct {
// typeInfo describes a single concrete Go type, which can be a basic or a named
// type. If it is a named type, it may have methods.
type typeInfo struct {
name string
typecode llvm.Value
methodSet llvm.Value
num uint64 // the type number after lowering
countMakeInterfaces int // how often this type is used in an interface
countTypeAsserts int // how often a type assert happens on this method
methods []*methodInfo
name string
typecode llvm.Value
methodSet llvm.Value
num uint64 // the type number after lowering
countTypeAsserts int // how often a type assert happens on this method
methods []*methodInfo
}
// getMethod looks up the method on this type with the given signature and
@@ -104,9 +104,6 @@ func (t typeInfoSlice) Less(i, j int) bool {
if t[i].countTypeAsserts != t[j].countTypeAsserts {
return t[i].countTypeAsserts < t[j].countTypeAsserts
}
if t[i].countMakeInterfaces != t[j].countMakeInterfaces {
return t[i].countMakeInterfaces < t[j].countMakeInterfaces
}
return t[i].name < t[j].name
}
func (t typeInfoSlice) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
@@ -115,6 +112,7 @@ func (t typeInfoSlice) Swap(i, j int) { t[i], t[j] = t[j], t[i] }
// methods it has.
type interfaceInfo struct {
name string // name with $interface suffix
methodSet llvm.Value // global which this interfaceInfo describes
signatures []*signatureInfo // method set
types typeInfoSlice // types this interface implements
assertFunc llvm.Value // runtime.interfaceImplements replacement
@@ -163,9 +161,9 @@ func LowerInterfaces(mod llvm.Module) error {
// run runs the pass itself.
func (p *lowerInterfacesPass) run() error {
// Collect all type codes.
typecodeIDPtr := llvm.PointerType(p.mod.GetTypeByName("runtime.typecodeID"), 0)
typeInInterfacePtr := llvm.PointerType(p.mod.GetTypeByName("runtime.typeInInterface"), 0)
var typesInInterfaces []llvm.Value
typecodeID := p.mod.GetTypeByName("runtime.typecodeID")
typecodeIDPtr := llvm.PointerType(typecodeID, 0)
var typecodeIDs []llvm.Value
for global := p.mod.FirstGlobal(); !global.IsNil(); global = llvm.NextGlobal(global) {
switch global.Type() {
case typecodeIDPtr:
@@ -174,32 +172,19 @@ func (p *lowerInterfacesPass) run() error {
// discarded afterwards.
name := global.Name()
if _, ok := p.types[name]; !ok {
p.types[name] = &typeInfo{
typecodeIDs = append(typecodeIDs, global)
t := &typeInfo{
name: name,
typecode: global,
}
}
case typeInInterfacePtr:
// Count per type how often it is put in an interface. Also, collect
// all methods this type has (if it is named).
typesInInterfaces = append(typesInInterfaces, global)
initializer := global.Initializer()
typecode := llvm.ConstExtractValue(initializer, []uint32{0})
methodSet := llvm.ConstExtractValue(initializer, []uint32{1})
typecodeName := typecode.Name()
t := p.types[typecodeName]
if t == nil {
t = &typeInfo{
name: typecodeName,
typecode: typecode,
p.types[name] = t
initializer := global.Initializer()
if initializer.IsNil() {
continue
}
p.types[typecodeName] = t
methodSet := llvm.ConstExtractValue(initializer, []uint32{2})
p.addTypeMethods(t, methodSet)
}
p.addTypeMethods(t, methodSet)
// Count the number of MakeInterface instructions, for sorting the
// typecodes later.
t.countMakeInterfaces += len(getUses(global))
}
}
@@ -363,18 +348,30 @@ func (p *lowerInterfacesPass) run() error {
// Assign a type code for each type.
assignTypeCodes(p.mod, typeSlice)
// Replace each use of a runtime.typeInInterface with the constant type
// Replace each use of a ptrtoint runtime.typecodeID with the constant type
// code.
for _, global := range typesInInterfaces {
for _, global := range typecodeIDs {
for _, use := range getUses(global) {
t := p.types[llvm.ConstExtractValue(global.Initializer(), []uint32{0}).Name()]
if use.IsAConstantExpr().IsNil() {
continue
}
t := p.types[global.Name()]
typecode := llvm.ConstInt(p.uintptrType, t.num, false)
switch use.Opcode() {
case llvm.PtrToInt:
// Already of the correct type.
case llvm.BitCast:
// Could happen when stored in an interface (which is of type
// i8*).
typecode = llvm.ConstIntToPtr(typecode, use.Type())
default:
panic("unexpected constant expression")
}
use.ReplaceAllUsesWith(typecode)
}
}
// Replace each type assert with an actual type comparison or (if the type
// assert is impossible) the constant false.
// Replace each type assert with an actual type comparison.
for _, use := range typeAssertUses {
actualType := use.Operand(0)
assertedTypeGlobal := use.Operand(1)
@@ -405,20 +402,36 @@ func (p *lowerInterfacesPass) run() error {
}
}
// Remove stray runtime.typeInInterface globals. Required for the following
// cleanup.
for _, global := range typesInInterfaces {
global.EraseFromParentAsGlobal()
}
// Remove method sets of types. Unnecessary, but cleans up the IR for
// inspection.
// Remove most objects created for interface and reflect lowering.
// Unnecessary, but cleans up the IR for inspection and testing.
zeroTypeCode := llvm.ConstNull(typecodeID)
for _, typ := range p.types {
// Only some typecodes have an initializer.
initializer := typ.typecode.Initializer()
if !initializer.IsNil() {
references := llvm.ConstExtractValue(initializer, []uint32{0})
typ.typecode.SetInitializer(zeroTypeCode)
if !references.IsAConstantExpr().IsNil() && references.Opcode() == llvm.BitCast {
// Structs have a 'references' field that is not a typecode but
// a pointer to a runtime.structField array and therefore a
// bitcast. This global should be erased separately, otherwise
// typecode objects cannot be erased.
structFields := references.Operand(0)
structFields.EraseFromParentAsGlobal()
}
}
if !typ.methodSet.IsNil() {
typ.methodSet.EraseFromParentAsGlobal()
typ.methodSet = llvm.Value{}
}
}
for _, itf := range p.interfaces {
// Remove method sets of interfaces.
itf.methodSet.EraseFromParentAsGlobal()
itf.methodSet = llvm.Value{}
}
return nil
}
@@ -437,9 +450,10 @@ func (p *lowerInterfacesPass) addTypeMethods(t *typeInfo, methodSet llvm.Value)
set := methodSet.Initializer() // get value from global
for i := 0; i < set.Type().ArrayLength(); i++ {
methodData := llvm.ConstExtractValue(set, []uint32{uint32(i)})
signatureName := llvm.ConstExtractValue(methodData, []uint32{0}).Name()
signatureGlobal := llvm.ConstExtractValue(methodData, []uint32{0})
signatureName := signatureGlobal.Name()
function := llvm.ConstExtractValue(methodData, []uint32{1}).Operand(0)
signature := p.getSignature(signatureName)
signature := p.getSignature(signatureName, signatureGlobal)
method := &methodInfo{
function: function,
signatureInfo: signature,
@@ -454,13 +468,15 @@ func (p *lowerInterfacesPass) addTypeMethods(t *typeInfo, methodSet llvm.Value)
func (p *lowerInterfacesPass) addInterface(methodSet llvm.Value) {
name := methodSet.Name()
t := &interfaceInfo{
name: name,
name: name,
methodSet: methodSet,
}
p.interfaces[name] = t
methodSet = methodSet.Initializer() // get global value from getelementptr
for i := 0; i < methodSet.Type().ArrayLength(); i++ {
signatureName := llvm.ConstExtractValue(methodSet, []uint32{uint32(i)}).Name()
signature := p.getSignature(signatureName)
signatureGlobal := llvm.ConstExtractValue(methodSet, []uint32{uint32(i)})
signatureName := signatureGlobal.Name()
signature := p.getSignature(signatureName, signatureGlobal)
signature.interfaces = append(signature.interfaces, t)
t.signatures = append(t.signatures, signature)
}
@@ -468,10 +484,11 @@ func (p *lowerInterfacesPass) addInterface(methodSet llvm.Value) {
// getSignature returns a new *signatureInfo, creating it if it doesn't already
// exist.
func (p *lowerInterfacesPass) getSignature(name string) *signatureInfo {
func (p *lowerInterfacesPass) getSignature(name string, global llvm.Value) *signatureInfo {
if _, ok := p.signatures[name]; !ok {
p.signatures[name] = &signatureInfo{
name: name,
name: name,
global: global,
}
}
return p.signatures[name]
transform/testdata/interface.ll
Vendored
+5 -9
View File
@@ -1,21 +1,17 @@
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv7m-none-eabi"
%runtime.typecodeID = type { %runtime.typecodeID*, i32 }
%runtime.typeInInterface = type { %runtime.typecodeID*, %runtime.interfaceMethodInfo* }
%runtime.typecodeID = type { %runtime.typecodeID*, i32, %runtime.interfaceMethodInfo* }
%runtime.interfaceMethodInfo = type { i8*, i32 }
@"reflect/types.type:basic:uint8" = external constant %runtime.typecodeID
@"reflect/types.type:basic:int" = external constant %runtime.typecodeID
@"typeInInterface:reflect/types.type:basic:uint8" = private constant %runtime.typeInInterface { %runtime.typecodeID* @"reflect/types.type:basic:uint8", %runtime.interfaceMethodInfo* null }
@"typeInInterface:reflect/types.type:basic:int" = private constant %runtime.typeInInterface { %runtime.typecodeID* @"reflect/types.type:basic:int", %runtime.interfaceMethodInfo* null }
@"func NeverImplementedMethod()" = external constant i8
@"Unmatched$interface" = private constant [1 x i8*] [i8* @"func NeverImplementedMethod()"]
@"func Double() int" = external constant i8
@"Doubler$interface" = private constant [1 x i8*] [i8* @"func Double() int"]
@"Number$methodset" = private constant [1 x %runtime.interfaceMethodInfo] [%runtime.interfaceMethodInfo { i8* @"func Double() int", i32 ptrtoint (i32 (i8*, i8*)* @"(Number).Double$invoke" to i32) }]
@"reflect/types.type:named:Number" = private constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:basic:int", i32 0 }
@"typeInInterface:reflect/types.type:named:Number" = private constant %runtime.typeInInterface { %runtime.typecodeID* @"reflect/types.type:named:Number", %runtime.interfaceMethodInfo* getelementptr inbounds ([1 x %runtime.interfaceMethodInfo], [1 x %runtime.interfaceMethodInfo]* @"Number$methodset", i32 0, i32 0) }
@"reflect/types.type:named:Number" = private constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:basic:int", i32 0, %runtime.interfaceMethodInfo* getelementptr inbounds ([1 x %runtime.interfaceMethodInfo], [1 x %runtime.interfaceMethodInfo]* @"Number$methodset", i32 0, i32 0) }
declare i1 @runtime.interfaceImplements(i32, i8**)
declare i1 @runtime.typeAssert(i32, %runtime.typecodeID*)
@@ -27,9 +23,9 @@ declare void @runtime.printnl()
declare void @runtime.nilPanic(i8*, i8*)
define void @printInterfaces() {
call void @printInterface(i32 ptrtoint (%runtime.typeInInterface* @"typeInInterface:reflect/types.type:basic:int" to i32), i8* inttoptr (i32 5 to i8*))
call void @printInterface(i32 ptrtoint (%runtime.typeInInterface* @"typeInInterface:reflect/types.type:basic:uint8" to i32), i8* inttoptr (i8 120 to i8*))
call void @printInterface(i32 ptrtoint (%runtime.typeInInterface* @"typeInInterface:reflect/types.type:named:Number" to i32), i8* inttoptr (i32 3 to i8*))
call void @printInterface(i32 ptrtoint (%runtime.typecodeID* @"reflect/types.type:basic:int" to i32), i8* inttoptr (i32 5 to i8*))
call void @printInterface(i32 ptrtoint (%runtime.typecodeID* @"reflect/types.type:basic:uint8" to i32), i8* inttoptr (i8 120 to i8*))
call void @printInterface(i32 ptrtoint (%runtime.typecodeID* @"reflect/types.type:named:Number" to i32), i8* inttoptr (i32 3 to i8*))
ret void
}
transform/testdata/interface.out.ll
Vendored
+3 -4
View File
@@ -1,15 +1,14 @@
target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-a:0:32-n32-S64"
target triple = "armv7m-none-eabi"
%runtime.typecodeID = type { %runtime.typecodeID*, i32 }
%runtime.typecodeID = type { %runtime.typecodeID*, i32, %runtime.interfaceMethodInfo* }
%runtime.interfaceMethodInfo = type { i8*, i32 }
@"reflect/types.type:basic:uint8" = external constant %runtime.typecodeID
@"reflect/types.type:basic:int" = external constant %runtime.typecodeID
@"func NeverImplementedMethod()" = external constant i8
@"Unmatched$interface" = private constant [1 x i8*] [i8* @"func NeverImplementedMethod()"]
@"func Double() int" = external constant i8
@"Doubler$interface" = private constant [1 x i8*] [i8* @"func Double() int"]
@"reflect/types.type:named:Number" = private constant %runtime.typecodeID { %runtime.typecodeID* @"reflect/types.type:basic:int", i32 0 }
@"reflect/types.type:named:Number" = private constant %runtime.typecodeID zeroinitializer
declare i1 @runtime.interfaceImplements(i32, i8**)