| commit | 532c199ee56cdbc2cfd12da1c1cfb3359b122c7c | [log] [tgz] |
|---|---|---|
| author | Austin Clements <austin@google.com> | Sat Oct 17 18:42:03 2020 -0400 |
| committer | Austin Clements <austin@google.com> | Mon Oct 26 14:50:38 2020 +0000 |
| tree | 15cd5602f750c46e64d4d7329fc84382f58cd9bb | |
| parent | 614a8b7c8ad42ff8a9bc363f813af2aae046fd0c [diff] |
runtime: fix sub-uintptr-sized Windows callback arguments The Windows callback support accepts Go functions with arguments that are uintptr-sized or smaller. However, it doesn't implement smaller arguments correctly. It assumes the Windows arguments layout is equivalent to the Go argument layout. This is often true, but because Windows C ABIs pad arguments to word size, while Go packs arguments, the layout is different if there are multiple sub-word-size arguments in a row. For example, a function with two uint16 arguments will have a two-word C argument frame, but only a 4 byte Go argument frame. There are also subtleties surrounding floating-point register arguments that it doesn't handle correctly. To fix this, when constructing a callback, we examine the Go function's signature to construct a mapping between the C argument frame and the Go argument frame. When the callback is invoked, we use this mapping to build the Go argument frame and copy the result back. This adds several test cases to TestStdcallAndCDeclCallbacks that exercise more complex function signatures. These all fail with the current code, but work with this CL. In addition to fixing these callback types, this is also a step toward the Go register ABI (#40724), which is going to make the ABI translation more complex. Change-Id: I19fb1681b659d9fd528ffd5e88912bebb95da052 Reviewed-on: https://go-review.googlesource.com/c/go/+/263271 Trust: Austin Clements <austin@google.com> Trust: Alex Brainman <alex.brainman@gmail.com> Run-TryBot: Austin Clements <austin@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Michael Knyszek <mknyszek@google.com> Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
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