cmd/gc: Method values + slicing arrays + inlining == Broken strings

[dominikh]

What steps will reproduce the problem?
If possible, include a link to a program on play.golang.org.
1. Compile and run http://play.golang.org/p/Yl6EXET0fc (can reproduce on the playground
as well)
2. Notice how the length for the second string becomes ridiculously big
3.

What is the expected output?
Not breaking the string

What do you see instead?
Broken strings that will cause Go to read memory it shouldn't.

Which compiler are you using (5g, 6g, 8g, gccgo)?
6g

Which operating system are you using?
Linux

Which version are you using?  (run 'go version')
This happens both with Go 1.1 and current tip (go version devel +56909cb770fe Fri Jun 21
18:07:57 2013 -0700 linux/amd64)

Please provide any additional information below.

1) This only happens when using method values. Function values are fine
2) This only happens when manually creating the backing array
3) Disabling inlining avoids the issue.

(Reporting this on behalf of Mikhail Panchenko who initially discovered this issue in a
more complex scenario)

[minux]

Comment 1:

Issue #5754 has been merged into this issue.

[DanielMorsing]

Comment 2:

Looks like a case of bad escape analysis. The broken method thunk allocates foo on the
stack.

Status changed to Accepted.

[ianlancetaylor]

Comment 3:

Labels changed: added priority-asap, go1.1.2, removed priority-triage.

[DanielMorsing]

Comment 4:

Fix at https://golang.org/cl/10383048

Owner changed to @DanielMorsing.

Status changed to Started.

[DanielMorsing]

Comment 5:

This issue was closed by revision 7cfa831.

Status changed to Fixed.

[adg]

Comment 6:

This issue was closed by revision e503b72350b2.