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Restrict lambda-blocks to occuring as function call arguments #851

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msullivan opened this issue Aug 19, 2011 · 2 comments
Closed

Restrict lambda-blocks to occuring as function call arguments #851

msullivan opened this issue Aug 19, 2011 · 2 comments

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@msullivan
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Right now they are permitted anywhere.
@msullivan
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Without doing this we are unsound, as you could assign a block to a lambda, deinitialize variables it refers to, and then call the lambda.

@graydon
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graydon commented Feb 14, 2012

I believe this is long-since obsolete.

@graydon graydon closed this as completed Feb 14, 2012
keeperofdakeys pushed a commit to keeperofdakeys/rust that referenced this issue Dec 12, 2017
@bors
Auto merge of rust-lang#851 - mneumann:dragonfly-several-fixes, r=ale…
5054b3c 
…xcrichton

Several fixes for DragonFly

With these changes in place, crate "nix" works (with some patches applied).
ZuseZ4 pushed a commit to EnzymeAD/rust that referenced this issue Mar 7, 2023
@wsmoses
Add acos (rust-lang#851)
1e82cd6
coastalwhite pushed a commit to coastalwhite/rust that referenced this issue Aug 5, 2023
@danielverkamp
Manually preserve rbx across cpuid instruction (rust-lang#851)
fb9bca9 
* Manually preserve rbx across cpuid instruction

This fixes an issue observed when using __cpuid and __cpuid_count with
Address Sanitizer enabled: the generated code uses the rbx register to
access ASAN tracking information without reloading it after cpuid,
resulting in a segfault since the rbx register is overwritten by cpuid
(https://crbug.com/1072045).

This seems like a compiler backend bug, and indeed there is a
long-standing LLVM bug report about a very similar issue:
https://bugs.llvm.org/show_bug.cgi?id=17907

To work around this issue, we can manually preserve the rbx register
contents in the inline assembly.  This is the approach taken by LLVM's
own host cpuid detection code (lib/Host/Support.cpp).  The original rbx
value is stashed in rsi, which is then swapped with rbx to restore the
original value as well as keep the output ebx value from the CPUID
instruction to be used as an output of the inline assembly.

The rbx clobber is also removed; this seems ineffective, and it
conflicts with the ebx output of the inline assembly (ebx is a
subregister of rbx): "Note that clobbering named registers that are also
present in output constraints is not legal."
(https://llvm.org/docs/LangRef.html#clobber-constraints)

* Add link to LLVM bug in cpuid workaround comment
celinval pushed a commit to celinval/rust-dev that referenced this issue Jun 4, 2024
@adpaco-aws @tedinski
Add test for likely and unlikely intrinsics. (rust-lang#851)
ef5385d 
* Add test for `likely` and `unlikely` intrinsics.

* Format

* Remove let statments
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@graydon @msullivan