From fcedf0beaa44c080e583c4b7eb6932f8ea4117e0 Mon Sep 17 00:00:00 2001
From: Ayke van Laethem <aykevanlaethem@gmail.com>
Date: Wed, 16 Sep 2020 01:07:46 +0200
Subject: [PATCH] stacksize: deal with DW_CFA_advance_loc1

In some cases this operation is emitted. It appears to be emitted when a
switch is lowered to a jump table in the ARM backend.
---
 stacksize/dwarf.go | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/stacksize/dwarf.go b/stacksize/dwarf.go
index 6186a8c2..d4e71427 100644
--- a/stacksize/dwarf.go
+++ b/stacksize/dwarf.go
@@ -207,6 +207,16 @@ func (fi *frameInfo) exec(bytecode []byte) ([]frameInfoLine, error) {
 			switch lowBits {
 			case 0: // DW_CFA_nop
 				// no operation
+			case 0x02: // DW_CFA_advance_loc1
+				// Very similar to DW_CFA_advance_loc but allows for a slightly
+				// larger range.
+				offset, err := r.ReadByte()
+				if err != nil {
+					return nil, err
+				}
+				fi.loc += uint64(offset) * fi.cie.codeAlignmentFactor
+				entries = append(entries, fi.newLine())
+				// TODO: DW_CFA_advance_loc2 etc
 			case 0x07: // DW_CFA_undefined
 				// Marks a single register as undefined. This is used to stop
 				// unwinding in tinygo_startTask using: