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Let replaceVTableHolder accept any type.#97
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alexcrichton merged 1 commit intorust-lang:rust-llvm-release-4-0-1from Nov 9, 2017
Merged
Let replaceVTableHolder accept any type.#97alexcrichton merged 1 commit intorust-lang:rust-llvm-release-4-0-1from
alexcrichton merged 1 commit intorust-lang:rust-llvm-release-4-0-1from
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In Rust, a trait can be implemented for any type, and if a trait object pointer is used for the type, then a virtual table will be emitted for that trait/type combination. We would like debuggers to be able to inspect trait objects, which requires finding the concrete type associated with a given vtable. This patch changes LLVM so that any type can be passed to replaceVTableHolder. This allows the Rust compiler to emit the needed debug info -- associating a vtable with the concrete type for which it was emitted. This is a DWARF extension: DWARF only specifies the meaning of DW_AT_containing_type in one specific situation. This style of DWARF extension is routine, though, and LLVM already has one such case for DW_AT_containing_type. Patch by Tom Tromey! Differential Revision: https://reviews.llvm.org/D39503 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317730 91177308-0d34-0410-b5e6-96231b3b80d8
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In Rust, a trait can be implemented for any type, and if a trait
object pointer is used for the type, then a virtual table will be
emitted for that trait/type combination.
We would like debuggers to be able to inspect trait objects, which
requires finding the concrete type associated with a given vtable.
This patch changes LLVM so that any type can be passed to
replaceVTableHolder. This allows the Rust compiler to emit the needed
debug info -- associating a vtable with the concrete type for which it
was emitted.
This is a DWARF extension: DWARF only specifies the meaning of
DW_AT_containing_type in one specific situation. This style of DWARF
extension is routine, though, and LLVM already has one such case for
DW_AT_containing_type.
This is a backport of this patch that went in upstream:
Differential Revision: https://reviews.llvm.org/D39503
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317730 91177308-0d34-0410-b5e6-96231b3b80d8