arm64: Add support for system calls (SVC)

Author: racerxdl

compiler/compiler.go

@@ -1336,12 +1336,14 @@ func (b *builder) createFunctionCall(instr *ssa.CallCommon) (llvm.Value, error)
 			return b.createMemoryCopyCall(fn, instr.Args)
 		case name == "runtime.memzero":
 			return b.createMemoryZeroCall(instr.Args)
-		case name == "device.Asm" || name == "device/arm.Asm" || name == "device/avr.Asm" || name == "device/riscv.Asm":
+		case name == "device.Asm" || name == "device/arm.Asm" || name == "device/arm64.Asm" || name == "device/avr.Asm" || name == "device/riscv.Asm":
 			return b.createInlineAsm(instr.Args)
-		case name == "device.AsmFull" || name == "device/arm.AsmFull" || name == "device/avr.AsmFull" || name == "device/riscv.AsmFull":
+		case name == "device.AsmFull" || name == "device/arm.AsmFull" || name == "device/arm64.AsmFull" || name == "device/avr.AsmFull" || name == "device/riscv.AsmFull":
 			return b.createInlineAsmFull(instr)
 		case strings.HasPrefix(name, "device/arm.SVCall"):
 			return b.emitSVCall(instr.Args)
+		case strings.HasPrefix(name, "device/arm64.SVCall"):
+			return b.emitSV64Call(instr.Args)
 		case strings.HasPrefix(name, "(device/riscv.CSR)."):
 			return b.emitCSROperation(instr)
 		case strings.HasPrefix(name, "syscall.Syscall"):

compiler/inlineasm.go

@@ -163,6 +163,44 @@ func (b *builder) emitSVCall(args []ssa.Value) (llvm.Value, error) {
 	return b.CreateCall(target, llvmArgs, ""), nil
 }
 
+// This is a compiler builtin which emits an inline SVCall instruction. It can
+// be one of:
+//
+//     func SVCall0(num uintptr) uintptr
+//     func SVCall1(num uintptr, a1 interface{}) uintptr
+//     func SVCall2(num uintptr, a1, a2 interface{}) uintptr
+//     func SVCall3(num uintptr, a1, a2, a3 interface{}) uintptr
+//     func SVCall4(num uintptr, a1, a2, a3, a4 interface{}) uintptr
+//
+// The num parameter must be a constant. All other parameters may be any scalar
+// value supported by LLVM inline assembly.
+// Same as emitSVCall but for AArch64
+func (b *builder) emitSV64Call(args []ssa.Value) (llvm.Value, error) {
+	num, _ := constant.Uint64Val(args[0].(*ssa.Const).Value)
+	llvmArgs := []llvm.Value{}
+	argTypes := []llvm.Type{}
+	asm := "svc #" + strconv.FormatUint(num, 10)
+	constraints := "={x0}"
+	for i, arg := range args[1:] {
+		arg = arg.(*ssa.MakeInterface).X
+		if i == 0 {
+			constraints += ",0"
+		} else {
+			constraints += ",{x" + strconv.Itoa(i) + "}"
+		}
+		llvmValue := b.getValue(arg)
+		llvmArgs = append(llvmArgs, llvmValue)
+		argTypes = append(argTypes, llvmValue.Type())
+	}
+	// Implement the ARM64 calling convention by marking x1-x7 as
+	// clobbered. x0 is used as an output register so doesn't have to be
+	// marked as clobbered.
+	constraints += ",~{x1},~{x2},~{x3},~{x4},~{x5},~{x6},~{x7}"
+	fnType := llvm.FunctionType(b.uintptrType, argTypes, false)
+	target := llvm.InlineAsm(fnType, asm, constraints, true, false, 0)
+	return b.CreateCall(target, llvmArgs, ""), nil
+}
+
 // This is a compiler builtin which emits CSR instructions. It can be one of:
 //
 //     func (csr CSR) Get() uintptr

src/device/arm64/arm64.go

@@ -0,0 +1,36 @@
+package arm64
+
+// Run the given assembly code. The code will be marked as having side effects,
+// as it doesn't produce output and thus would normally be eliminated by the
+// optimizer.
+func Asm(asm string)
+
+// Run the given inline assembly. The code will be marked as having side
+// effects, as it would otherwise be optimized away. The inline assembly string
+// recognizes template values in the form {name}, like so:
+//
+//     arm.AsmFull(
+//         "str {value}, {result}",
+//         map[string]interface{}{
+//             "value":  1
+//             "result": &dest,
+//         })
+//
+// You can use {} in the asm string (which expands to a register) to set the
+// return value.
+func AsmFull(asm string, regs map[string]interface{}) uintptr
+
+// Run the following system call (SVCall) with 0 arguments.
+func SVCall0(num uintptr) uintptr
+
+// Run the following system call (SVCall) with 1 argument.
+func SVCall1(num uintptr, a1 interface{}) uintptr
+
+// Run the following system call (SVCall) with 2 arguments.
+func SVCall2(num uintptr, a1, a2 interface{}) uintptr
+
+// Run the following system call (SVCall) with 3 arguments.
+func SVCall3(num uintptr, a1, a2, a3 interface{}) uintptr
+
+// Run the following system call (SVCall) with 4 arguments.
+func SVCall4(num uintptr, a1, a2, a3, a4 interface{}) uintptr