Commit 05abce5

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Auto merge of #146059 - folkertdev:va-end-lifetime, r=saethlin

explicitly end the lifetime of `va_list` tracking issue: #44930 split out from: #144549 The `va_list` is created in the compiler itself when the variable argument list `...` is desugared, and hence the lifetime end is not inserted automatically. The value can't outlive the function in which it was created, so it is correct to end the lifetime here. Ending the lifetime explicitly also appears to give slightly better codegen in #144549. I also included a little drive-by improvement to not cast pointers to integers and back again. r? codegen

2 parents 75ee9ff + 213bb87 commit 05abce5Copy full SHA for 05abce5

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2 files changed

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lines changed

compiler
- rustc_codegen_llvm/src
  - va_arg.rs
- rustc_codegen_ssa/src/mir
  - block.rs

2 files changed

-3

lines changed

`‎compiler/rustc_codegen_llvm/src/va_arg.rs`

Lines changed: 6 additions & 3 deletions

Original file line number	Diff line number	Diff line change
`@@ -28,9 +28,12 @@ fn round_pointer_up_to_alignment<'ll>(`
`28`	`28`	`align: Align,`
`29`	`29`	`ptr_ty: &'ll Type,`
`30`	`30`	`) -> &'ll Value {`
`31`		`- let mut ptr_as_int = bx.ptrtoint(addr, bx.cx().type_isize());`
`32`		`- ptr_as_int = round_up_to_alignment(bx, ptr_as_int, align);`
`33`		`- bx.inttoptr(ptr_as_int, ptr_ty)`
	`31`	`+ let ptr = bx.inbounds_ptradd(addr, bx.const_i32(align.bytes() as i32 - 1));`
	`32`	`+ bx.call_intrinsic(`
	`33`	`+ "llvm.ptrmask",`
	`34`	`+ &[ptr_ty, bx.type_i32()],`
	`35`	`+ &[ptr, bx.const_int(bx.isize_ty, -(align.bytes() as isize) as i64)],`
	`36`	`+ )`
`34`	`37`	`}`
`35`	`38`
`36`	`39`	`fn emit_direct_ptr_va_arg<'ll, 'tcx>(`

`‎compiler/rustc_codegen_ssa/src/mir/block.rs`

Lines changed: 3 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -519,6 +519,9 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {`
`519`	`519`	`match self.locals[mir::Local::from_usize(1 + va_list_arg_idx)] {`
`520`	`520`	`LocalRef::Place(va_list) => {`
`521`	`521`	`bx.va_end(va_list.val.llval);`
	`522`	`+`
	`523`	+ // Explicitly end the lifetime of the `va_list`, this matters for LLVM.
	`524`	`+ bx.lifetime_end(va_list.val.llval, va_list.layout.size);`
`522`	`525`	`}`
`523`	`526`	_ => bug!("C-variadic function must have a `VaList` place"),
`524`	`527`	`}`

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Commit 05abce5

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2 files changed

2 files changed

`‎compiler/rustc_codegen_llvm/src/va_arg.rs`

`‎compiler/rustc_codegen_ssa/src/mir/block.rs`

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