b4c90f3677
This commit changes many things:
* Most interface-related operations are moved into an optimization
pass for more modularity. IR construction creates pseudo-calls which
are lowered in this pass.
* Type codes are assigned in this interface lowering pass, after DCE.
* Type codes are sorted by usage: types more often used in type
asserts are assigned lower numbers to ease jump table construction
during machine code generation.
* Interface assertions are optimized: they are replaced by constant
false, comparison against a constant, or a typeswitch with only
concrete types in the general case.
* Interface calls are replaced with unreachable, direct calls, or a
concrete type switch with direct calls depending on the number of
implementing types. This hopefully makes some interface patterns
zero-cost.
These changes lead to a ~0.5K reduction in code size on Cortex-M for
testdata/interface.go. It appears that a major cause for this is the
replacement of function pointers with direct calls, which are far more
susceptible to optimization. Also, not having a fixed global array of
function pointers greatly helps dead code elimination.
This change also makes future optimizations easier, like optimizations
on interface value comparisons.
452 строки
18 КиБ
Go
452 строки
18 КиБ
Go
package interp
|
|
|
|
// This file implements the core interpretation routines, interpreting single
|
|
// functions.
|
|
|
|
import (
|
|
"errors"
|
|
"strings"
|
|
|
|
"github.com/aykevl/go-llvm"
|
|
)
|
|
|
|
type frame struct {
|
|
*Eval
|
|
fn llvm.Value
|
|
pkgName string
|
|
locals map[llvm.Value]Value
|
|
}
|
|
|
|
// evalBasicBlock evaluates a single basic block, returning the return value (if
|
|
// ending with a ret instruction), a list of outgoing basic blocks (if not
|
|
// ending with a ret instruction), or an error on failure.
|
|
// Most of it works at compile time. Some calls get translated into calls to be
|
|
// executed at runtime: calls to functions with side effects, external calls,
|
|
// and operations on the result of such instructions.
|
|
func (fr *frame) evalBasicBlock(bb, incoming llvm.BasicBlock, indent string) (retval Value, outgoing []llvm.Value, err error) {
|
|
for inst := bb.FirstInstruction(); !inst.IsNil(); inst = llvm.NextInstruction(inst) {
|
|
if fr.Debug {
|
|
print(indent)
|
|
inst.Dump()
|
|
println()
|
|
}
|
|
switch {
|
|
case !inst.IsABinaryOperator().IsNil():
|
|
lhs := fr.getLocal(inst.Operand(0)).(*LocalValue).Underlying
|
|
rhs := fr.getLocal(inst.Operand(1)).(*LocalValue).Underlying
|
|
|
|
switch inst.InstructionOpcode() {
|
|
// Standard binary operators
|
|
case llvm.Add:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateAdd(lhs, rhs, "")}
|
|
case llvm.FAdd:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFAdd(lhs, rhs, "")}
|
|
case llvm.Sub:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateSub(lhs, rhs, "")}
|
|
case llvm.FSub:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFSub(lhs, rhs, "")}
|
|
case llvm.Mul:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateMul(lhs, rhs, "")}
|
|
case llvm.FMul:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFMul(lhs, rhs, "")}
|
|
case llvm.UDiv:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateUDiv(lhs, rhs, "")}
|
|
case llvm.SDiv:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateSDiv(lhs, rhs, "")}
|
|
case llvm.FDiv:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFDiv(lhs, rhs, "")}
|
|
case llvm.URem:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateURem(lhs, rhs, "")}
|
|
case llvm.SRem:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateSRem(lhs, rhs, "")}
|
|
case llvm.FRem:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFRem(lhs, rhs, "")}
|
|
|
|
// Logical operators
|
|
case llvm.Shl:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateShl(lhs, rhs, "")}
|
|
case llvm.LShr:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateLShr(lhs, rhs, "")}
|
|
case llvm.AShr:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateAShr(lhs, rhs, "")}
|
|
case llvm.And:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateAnd(lhs, rhs, "")}
|
|
case llvm.Or:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateOr(lhs, rhs, "")}
|
|
case llvm.Xor:
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateXor(lhs, rhs, "")}
|
|
|
|
default:
|
|
return nil, nil, &Unsupported{inst}
|
|
}
|
|
|
|
// Memory operators
|
|
case !inst.IsAAllocaInst().IsNil():
|
|
fr.locals[inst] = &AllocaValue{
|
|
Underlying: getZeroValue(inst.Type().ElementType()),
|
|
Dirty: false,
|
|
Eval: fr.Eval,
|
|
}
|
|
case !inst.IsALoadInst().IsNil():
|
|
operand := fr.getLocal(inst.Operand(0))
|
|
var value llvm.Value
|
|
if !operand.IsConstant() || inst.IsVolatile() {
|
|
value = fr.builder.CreateLoad(operand.Value(), inst.Name())
|
|
} else {
|
|
value = operand.Load()
|
|
}
|
|
if value.Type() != inst.Type() {
|
|
panic("interp: load: type does not match")
|
|
}
|
|
fr.locals[inst] = fr.getValue(value)
|
|
case !inst.IsAStoreInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
ptr := fr.getLocal(inst.Operand(1))
|
|
if inst.IsVolatile() {
|
|
fr.builder.CreateStore(value.Value(), ptr.Value())
|
|
} else {
|
|
ptr.Store(value.Value())
|
|
}
|
|
case !inst.IsAGetElementPtrInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
llvmIndices := make([]llvm.Value, inst.OperandsCount()-1)
|
|
for i := range llvmIndices {
|
|
llvmIndices[i] = inst.Operand(i + 1)
|
|
}
|
|
indices := make([]uint32, len(llvmIndices))
|
|
for i, llvmIndex := range llvmIndices {
|
|
operand := fr.getLocal(llvmIndex)
|
|
if !operand.IsConstant() {
|
|
// Not a constant operation.
|
|
// This should be detected by the scanner, but isn't at the
|
|
// moment.
|
|
panic("todo: non-const gep")
|
|
}
|
|
indices[i] = uint32(operand.Value().ZExtValue())
|
|
}
|
|
result := value.GetElementPtr(indices)
|
|
if result.Type() != inst.Type() {
|
|
println(" expected:", inst.Type().String())
|
|
println(" actual: ", result.Type().String())
|
|
panic("interp: gep: type does not match")
|
|
}
|
|
fr.locals[inst] = result
|
|
|
|
// Cast operators
|
|
case !inst.IsATruncInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateTrunc(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAZExtInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateZExt(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsASExtInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateSExt(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAFPToUIInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFPToUI(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAFPToSIInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFPToSI(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAUIToFPInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateUIToFP(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsASIToFPInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateSIToFP(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAFPTruncInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFPTrunc(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAFPExtInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFPExt(value.(*LocalValue).Value(), inst.Type(), "")}
|
|
case !inst.IsAPtrToIntInst().IsNil():
|
|
value := fr.getLocal(inst.Operand(0))
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreatePtrToInt(value.Value(), inst.Type(), "")}
|
|
case !inst.IsABitCastInst().IsNil() && inst.Type().TypeKind() == llvm.PointerTypeKind:
|
|
operand := inst.Operand(0)
|
|
if !operand.IsACallInst().IsNil() {
|
|
fn := operand.CalledValue()
|
|
if !fn.IsAFunction().IsNil() && fn.Name() == "runtime.alloc" {
|
|
continue // special case: bitcast of alloc
|
|
}
|
|
}
|
|
value := fr.getLocal(operand)
|
|
if bc, ok := value.(*PointerCastValue); ok {
|
|
value = bc.Underlying // avoid double bitcasts
|
|
}
|
|
fr.locals[inst] = &PointerCastValue{Eval: fr.Eval, Underlying: value, CastType: inst.Type()}
|
|
|
|
// Other operators
|
|
case !inst.IsAICmpInst().IsNil():
|
|
lhs := fr.getLocal(inst.Operand(0)).(*LocalValue).Underlying
|
|
rhs := fr.getLocal(inst.Operand(1)).(*LocalValue).Underlying
|
|
predicate := inst.IntPredicate()
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateICmp(predicate, lhs, rhs, "")}
|
|
case !inst.IsAFCmpInst().IsNil():
|
|
lhs := fr.getLocal(inst.Operand(0)).(*LocalValue).Underlying
|
|
rhs := fr.getLocal(inst.Operand(1)).(*LocalValue).Underlying
|
|
predicate := inst.FloatPredicate()
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateFCmp(predicate, lhs, rhs, "")}
|
|
case !inst.IsAPHINode().IsNil():
|
|
for i := 0; i < inst.IncomingCount(); i++ {
|
|
if inst.IncomingBlock(i) == incoming {
|
|
fr.locals[inst] = fr.getLocal(inst.IncomingValue(i))
|
|
}
|
|
}
|
|
case !inst.IsACallInst().IsNil():
|
|
callee := inst.CalledValue()
|
|
switch {
|
|
case callee.Name() == "runtime.alloc":
|
|
// heap allocation
|
|
users := getUses(inst)
|
|
var resultInst = inst
|
|
if len(users) == 1 && !users[0].IsABitCastInst().IsNil() {
|
|
// happens when allocating something other than i8*
|
|
resultInst = users[0]
|
|
}
|
|
size := fr.getLocal(inst.Operand(0)).(*LocalValue).Underlying.ZExtValue()
|
|
allocType := resultInst.Type().ElementType()
|
|
typeSize := fr.TargetData.TypeAllocSize(allocType)
|
|
elementCount := 1
|
|
if size != typeSize {
|
|
// allocate an array
|
|
if size%typeSize != 0 {
|
|
return nil, nil, &Unsupported{inst}
|
|
}
|
|
elementCount = int(size / typeSize)
|
|
allocType = llvm.ArrayType(allocType, elementCount)
|
|
}
|
|
alloc := llvm.AddGlobal(fr.Mod, allocType, fr.pkgName+"$alloc")
|
|
alloc.SetInitializer(getZeroValue(allocType))
|
|
alloc.SetLinkage(llvm.InternalLinkage)
|
|
result := &GlobalValue{
|
|
Underlying: alloc,
|
|
Eval: fr.Eval,
|
|
}
|
|
if elementCount == 1 {
|
|
fr.locals[resultInst] = result
|
|
} else {
|
|
fr.locals[resultInst] = result.GetElementPtr([]uint32{0, 0})
|
|
}
|
|
case callee.Name() == "runtime.hashmapMake":
|
|
// create a map
|
|
keySize := inst.Operand(0).ZExtValue()
|
|
valueSize := inst.Operand(1).ZExtValue()
|
|
fr.locals[inst] = &MapValue{
|
|
Eval: fr.Eval,
|
|
PkgName: fr.pkgName,
|
|
KeySize: int(keySize),
|
|
ValueSize: int(valueSize),
|
|
}
|
|
case callee.Name() == "runtime.hashmapStringSet":
|
|
// set a string key in the map
|
|
m := fr.getLocal(inst.Operand(0)).(*MapValue)
|
|
keyBuf := fr.getLocal(inst.Operand(1))
|
|
keyLen := fr.getLocal(inst.Operand(2))
|
|
valPtr := fr.getLocal(inst.Operand(3))
|
|
m.PutString(keyBuf, keyLen, valPtr)
|
|
case callee.Name() == "runtime.hashmapBinarySet":
|
|
// set a binary (int etc.) key in the map
|
|
// TODO: unimplemented
|
|
case callee.Name() == "runtime.stringConcat":
|
|
// adding two strings together
|
|
buf1Ptr := fr.getLocal(inst.Operand(0))
|
|
buf1Len := fr.getLocal(inst.Operand(1))
|
|
buf2Ptr := fr.getLocal(inst.Operand(2))
|
|
buf2Len := fr.getLocal(inst.Operand(3))
|
|
buf1 := getStringBytes(buf1Ptr, buf1Len.Value())
|
|
buf2 := getStringBytes(buf2Ptr, buf2Len.Value())
|
|
result := []byte(string(buf1) + string(buf2))
|
|
vals := make([]llvm.Value, len(result))
|
|
for i := range vals {
|
|
vals[i] = llvm.ConstInt(fr.Mod.Context().Int8Type(), uint64(result[i]), false)
|
|
}
|
|
globalType := llvm.ArrayType(fr.Mod.Context().Int8Type(), len(result))
|
|
globalValue := llvm.ConstArray(fr.Mod.Context().Int8Type(), vals)
|
|
global := llvm.AddGlobal(fr.Mod, globalType, fr.pkgName+"$stringconcat")
|
|
global.SetInitializer(globalValue)
|
|
global.SetLinkage(llvm.InternalLinkage)
|
|
global.SetGlobalConstant(true)
|
|
global.SetUnnamedAddr(true)
|
|
stringType := fr.Mod.GetTypeByName("runtime._string")
|
|
retPtr := llvm.ConstGEP(global, getLLVMIndices(fr.Mod.Context().Int32Type(), []uint32{0, 0}))
|
|
retLen := llvm.ConstInt(stringType.StructElementTypes()[1], uint64(len(result)), false)
|
|
ret := getZeroValue(stringType)
|
|
ret = llvm.ConstInsertValue(ret, retPtr, []uint32{0})
|
|
ret = llvm.ConstInsertValue(ret, retLen, []uint32{1})
|
|
fr.locals[inst] = &LocalValue{fr.Eval, ret}
|
|
case callee.Name() == "runtime.stringToBytes":
|
|
// convert a string to a []byte
|
|
bufPtr := fr.getLocal(inst.Operand(0))
|
|
bufLen := fr.getLocal(inst.Operand(1))
|
|
result := getStringBytes(bufPtr, bufLen.Value())
|
|
vals := make([]llvm.Value, len(result))
|
|
for i := range vals {
|
|
vals[i] = llvm.ConstInt(fr.Mod.Context().Int8Type(), uint64(result[i]), false)
|
|
}
|
|
globalType := llvm.ArrayType(fr.Mod.Context().Int8Type(), len(result))
|
|
globalValue := llvm.ConstArray(fr.Mod.Context().Int8Type(), vals)
|
|
global := llvm.AddGlobal(fr.Mod, globalType, fr.pkgName+"$bytes")
|
|
global.SetInitializer(globalValue)
|
|
global.SetLinkage(llvm.InternalLinkage)
|
|
global.SetGlobalConstant(true)
|
|
global.SetUnnamedAddr(true)
|
|
sliceType := inst.Type()
|
|
retPtr := llvm.ConstGEP(global, getLLVMIndices(fr.Mod.Context().Int32Type(), []uint32{0, 0}))
|
|
retLen := llvm.ConstInt(sliceType.StructElementTypes()[1], uint64(len(result)), false)
|
|
ret := getZeroValue(sliceType)
|
|
ret = llvm.ConstInsertValue(ret, retPtr, []uint32{0}) // ptr
|
|
ret = llvm.ConstInsertValue(ret, retLen, []uint32{1}) // len
|
|
ret = llvm.ConstInsertValue(ret, retLen, []uint32{2}) // cap
|
|
fr.locals[inst] = &LocalValue{fr.Eval, ret}
|
|
case callee.Name() == "runtime.makeInterface":
|
|
fr.locals[inst] = &LocalValue{fr.Eval, llvm.ConstPtrToInt(inst.Operand(0), fr.TargetData.IntPtrType())}
|
|
case strings.HasPrefix(callee.Name(), "runtime.print") || callee.Name() == "runtime._panic":
|
|
// all print instructions, which necessarily have side
|
|
// effects but no results
|
|
var params []llvm.Value
|
|
for i := 0; i < inst.OperandsCount()-1; i++ {
|
|
operand := fr.getLocal(inst.Operand(i)).Value()
|
|
fr.markDirty(operand)
|
|
params = append(params, operand)
|
|
}
|
|
// TODO: accurate debug info, including call chain
|
|
fr.builder.CreateCall(callee, params, inst.Name())
|
|
case !callee.IsAFunction().IsNil() && callee.IsDeclaration():
|
|
// external functions
|
|
var params []llvm.Value
|
|
for i := 0; i < inst.OperandsCount()-1; i++ {
|
|
operand := fr.getLocal(inst.Operand(i)).Value()
|
|
fr.markDirty(operand)
|
|
params = append(params, operand)
|
|
}
|
|
// TODO: accurate debug info, including call chain
|
|
result := fr.builder.CreateCall(callee, params, inst.Name())
|
|
if inst.Type().TypeKind() != llvm.VoidTypeKind {
|
|
fr.markDirty(result)
|
|
fr.locals[inst] = &LocalValue{fr.Eval, result}
|
|
}
|
|
case !callee.IsAFunction().IsNil():
|
|
// regular function
|
|
var params []Value
|
|
dirtyParams := false
|
|
for i := 0; i < inst.OperandsCount()-1; i++ {
|
|
local := fr.getLocal(inst.Operand(i))
|
|
if !local.IsConstant() {
|
|
dirtyParams = true
|
|
}
|
|
params = append(params, local)
|
|
}
|
|
var ret Value
|
|
scanResult := fr.Eval.hasSideEffects(callee)
|
|
if scanResult.severity == sideEffectLimited || dirtyParams && scanResult.severity != sideEffectAll {
|
|
// Side effect is bounded. This means the operation invokes
|
|
// side effects (like calling an external function) but it
|
|
// is known at compile time which side effects it invokes.
|
|
// This means the function can be called at runtime and the
|
|
// affected globals can be marked dirty at compile time.
|
|
llvmParams := make([]llvm.Value, len(params))
|
|
for i, param := range params {
|
|
llvmParams[i] = param.Value()
|
|
}
|
|
result := fr.builder.CreateCall(callee, llvmParams, inst.Name())
|
|
ret = &LocalValue{fr.Eval, result}
|
|
// mark all mentioned globals as dirty
|
|
for global := range scanResult.mentionsGlobals {
|
|
fr.markDirty(global)
|
|
}
|
|
} else {
|
|
// Side effect is one of:
|
|
// * None: no side effects, can be fully interpreted at
|
|
// compile time.
|
|
// * Unbounded: cannot call at runtime so we'll try to
|
|
// interpret anyway and hope for the best.
|
|
ret, err = fr.function(callee, params, fr.pkgName, indent+" ")
|
|
if err != nil {
|
|
return nil, nil, err
|
|
}
|
|
}
|
|
if inst.Type().TypeKind() != llvm.VoidTypeKind {
|
|
fr.locals[inst] = ret
|
|
}
|
|
default:
|
|
// function pointers, etc.
|
|
return nil, nil, &Unsupported{inst}
|
|
}
|
|
case !inst.IsAExtractValueInst().IsNil():
|
|
agg := fr.getLocal(inst.Operand(0)).(*LocalValue) // must be constant
|
|
indices := inst.Indices()
|
|
if agg.Underlying.IsConstant() {
|
|
newValue := llvm.ConstExtractValue(agg.Underlying, indices)
|
|
fr.locals[inst] = fr.getValue(newValue)
|
|
} else {
|
|
if len(indices) != 1 {
|
|
return nil, nil, errors.New("cannot handle extractvalue with not exactly 1 index")
|
|
}
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateExtractValue(agg.Underlying, int(indices[0]), inst.Name())}
|
|
}
|
|
case !inst.IsAInsertValueInst().IsNil():
|
|
agg := fr.getLocal(inst.Operand(0)).(*LocalValue) // must be constant
|
|
val := fr.getLocal(inst.Operand(1))
|
|
indices := inst.Indices()
|
|
if agg.IsConstant() && val.IsConstant() {
|
|
newValue := llvm.ConstInsertValue(agg.Underlying, val.Value(), indices)
|
|
fr.locals[inst] = &LocalValue{fr.Eval, newValue}
|
|
} else {
|
|
if len(indices) != 1 {
|
|
return nil, nil, errors.New("cannot handle insertvalue with not exactly 1 index")
|
|
}
|
|
fr.locals[inst] = &LocalValue{fr.Eval, fr.builder.CreateInsertValue(agg.Underlying, val.Value(), int(indices[0]), inst.Name())}
|
|
}
|
|
|
|
case !inst.IsAReturnInst().IsNil() && inst.OperandsCount() == 0:
|
|
return nil, nil, nil // ret void
|
|
case !inst.IsAReturnInst().IsNil() && inst.OperandsCount() == 1:
|
|
return fr.getLocal(inst.Operand(0)), nil, nil
|
|
case !inst.IsABranchInst().IsNil() && inst.OperandsCount() == 3:
|
|
// conditional branch (if/then/else)
|
|
cond := fr.getLocal(inst.Operand(0)).Value()
|
|
if cond.Type() != fr.Mod.Context().Int1Type() {
|
|
panic("expected an i1 in a branch instruction")
|
|
}
|
|
thenBB := inst.Operand(1)
|
|
elseBB := inst.Operand(2)
|
|
if !cond.IsConstant() {
|
|
return nil, nil, errors.New("interp: branch on a non-constant")
|
|
} else {
|
|
switch cond.ZExtValue() {
|
|
case 0: // false
|
|
return nil, []llvm.Value{thenBB}, nil // then
|
|
case 1: // true
|
|
return nil, []llvm.Value{elseBB}, nil // else
|
|
default:
|
|
panic("branch was not true or false")
|
|
}
|
|
}
|
|
case !inst.IsABranchInst().IsNil() && inst.OperandsCount() == 1:
|
|
// unconditional branch (goto)
|
|
return nil, []llvm.Value{inst.Operand(0)}, nil
|
|
case !inst.IsAUnreachableInst().IsNil():
|
|
// unreachable was reached (e.g. after a call to panic())
|
|
// assume this is actually unreachable when running
|
|
return &LocalValue{fr.Eval, llvm.Undef(fr.fn.Type())}, nil, nil
|
|
|
|
default:
|
|
return nil, nil, &Unsupported{inst}
|
|
}
|
|
}
|
|
|
|
panic("interp: reached end of basic block without terminator")
|
|
}
|
|
|
|
// Get the Value for an operand, which is a constant value of some sort.
|
|
func (fr *frame) getLocal(v llvm.Value) Value {
|
|
if ret, ok := fr.locals[v]; ok {
|
|
return ret
|
|
} else if value := fr.getValue(v); value != nil {
|
|
return value
|
|
} else {
|
|
panic("cannot find value")
|
|
}
|
|
}
|