cmd/cgo: fix initialization of empty argument types

CL 258938 changed the way C to Go calls work such that they now
construct a C struct on the C side for the arguments and space for the
results. Any pointers in the result space must be zeroed, so we just
zero the whole struct.

However, C makes it surprisingly hard to robustly zero any struct
type. We had used a "{0}" initializer, which works in the vast
majority of cases, but fails if the type is empty or effectively

This CL fixes this by changing how the cgo tool zero-initializes the
argument struct to be more robust.

Fixes #42495.

Change-Id: Id1749b9d751e59eb7a02a9d44fec0698a2bf63cd
Trust: Austin Clements <>
Run-TryBot: Austin Clements <>
TryBot-Result: Go Bot <>
Reviewed-by: Cherry Zhang <>
Reviewed-by: Ian Lance Taylor <>
2 files changed
tree: 3b920dec7950a8e483710eeed9b84d06bcb125a1
  1. .gitattributes
  2. .github/
  3. .gitignore
  11. api/
  12. doc/
  13. favicon.ico
  14. lib/
  15. misc/
  16. robots.txt
  17. src/
  18. test/

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