From 6a0927d8c18d62d131e0ecda945398c3bb0ffa1a Mon Sep 17 00:00:00 2001
From: LemonBoy <thatlemon@gmail.com>
Date: Wed, 26 Feb 2020 21:41:29 +0100
Subject: [PATCH] debug: Fix end-of-stream condition in DWARF parser

---
 lib/std/dwarf.zig              | 10 ++++++----
 lib/std/io/seekable_stream.zig |  4 ++--
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/std/dwarf.zig b/lib/std/dwarf.zig
index f174e38555..32a49b68e0 100644
--- a/lib/std/dwarf.zig
+++ b/lib/std/dwarf.zig
@@ -417,9 +417,9 @@ pub const DwarfInfo = struct {
         var s = io.SliceSeekableInStream.init(di.debug_info);
         var this_unit_offset: u64 = 0;
 
-        while (true) {
+        while (this_unit_offset < try s.seekable_stream.getEndPos()) {
             s.seekable_stream.seekTo(this_unit_offset) catch |err| switch (err) {
-                error.EndOfStream => return,
+                error.EndOfStream => unreachable,
                 else => return err,
             };
 
@@ -445,6 +445,8 @@ pub const DwarfInfo = struct {
 
             while ((try s.seekable_stream.getPos()) < next_unit_pos) {
                 const die_obj = (try di.parseDie(&s.stream, abbrev_table, is_64)) orelse continue;
+                defer die_obj.attrs.deinit();
+
                 const after_die_offset = try s.seekable_stream.getPos();
 
                 switch (die_obj.tag_id) {
@@ -520,9 +522,9 @@ pub const DwarfInfo = struct {
         var s = io.SliceSeekableInStream.init(di.debug_info);
         var this_unit_offset: u64 = 0;
 
-        while (true) {
+        while (this_unit_offset < try s.seekable_stream.getEndPos()) {
             s.seekable_stream.seekTo(this_unit_offset) catch |err| switch (err) {
-                error.EndOfStream => return,
+                error.EndOfStream => unreachable,
                 else => return err,
             };
 
diff --git a/lib/std/io/seekable_stream.zig b/lib/std/io/seekable_stream.zig
index 48dc31b785..052abbc856 100644
--- a/lib/std/io/seekable_stream.zig
+++ b/lib/std/io/seekable_stream.zig
@@ -73,7 +73,7 @@ pub const SliceSeekableInStream = struct {
     fn seekToFn(in_stream: *SeekableInStream, pos: u64) SeekError!void {
         const self = @fieldParentPtr(Self, "seekable_stream", in_stream);
         const usize_pos = @intCast(usize, pos);
-        if (usize_pos >= self.slice.len) return error.EndOfStream;
+        if (usize_pos > self.slice.len) return error.EndOfStream;
         self.pos = usize_pos;
     }
 
@@ -86,7 +86,7 @@ pub const SliceSeekableInStream = struct {
             self.pos -= abs_amt;
         } else {
             const usize_amt = @intCast(usize, amt);
-            if (self.pos + usize_amt >= self.slice.len) return error.EndOfStream;
+            if (self.pos + usize_amt > self.slice.len) return error.EndOfStream;
             self.pos += usize_amt;
         }
     }