Wasmtime GitHub notifications bot (Aug 04 2022 at 21:04): Wasmtime GitHub notifications bot (Aug 04 2022 at 21:04):uweigand opened PR #4616 from s390x-tls-value to main:
Implement the tls_value for s390 in the ELF general-dynamic mode.
Notable differences to the x86_64 implementation are:
- We use a __tls_get_offset libcall instead of __tls_get_addr.
The current thread pointer (stored in a pair of access registers)
needs to be added to the result of __tls_get_offset.__tls_get_offset has a variant ABI that requires the address of
the GOT (global offset table) is passed in %r12.This means we need new libcall entries for __tls_get_offset and
the _GLOBAL_OFFSET_TABLE_ symbol. The latter is a bit weird in
that it is not actually a function, so "libcall" seems a bit
inappropiate. But there currently is no way, apart from the
libcall mechanism, so refer to a well-known global symbol by name.We also need to emit a relocation on a symbol placed in a
constant pool, as well as an extra relocation on the call
to __tls_get_offset required for TLS linker optimization.Needed by the cg_clif frontend.
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Wasmtime GitHub notifications bot (Aug 05 2022 at 11:57):uweigand updated PR #4616 from s390x-tls-value to main.
Wasmtime GitHub notifications bot (Aug 05 2022 at 15:17):uweigand updated PR #4616 from s390x-tls-value to main.
Wasmtime GitHub notifications bot (Aug 05 2022 at 16:04):uweigand updated PR #4616 from s390x-tls-value to main.
Wasmtime GitHub notifications bot (Aug 09 2022 at 20:51):uweigand edited PR #4616 from s390x-tls-value to main:
Implement the tls_value for s390 in the ELF general-dynamic mode.
Notable differences to the x86_64 implementation are:
- We use a
__tls_get_offsetlibcall instead of__tls_get_addr.The current thread pointer (stored in a pair of access registers)
needs to be added to the result of__tls_get_offset.
__tls_get_offsethas a variant ABI that requires the address of
the GOT (global offset table) is passed in %r12.This means we need a new libcall entries for
__tls_get_offset.
In addition, we also need a way to access_GLOBAL_OFFSET_TABLE_.
The latter is a "magic" symbol with a well-known name defined
by the ABI and recognized by the linker. This patch introduces
a newExternalName::KnownSymbolvariant to support such names
(originally due to @afonso360).We also need to emit a relocation on a symbol placed in a
constant pool, as well as an extra relocation on the call
to__tls_get_offsetrequired for TLS linker optimization.Needed by the cg_clif frontend.
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the PR.
[ ] This has been discussed in issue #..., or if not, please tell us why
here.[ ] A short description of what this does, why it is needed; if the
description becomes long, the matter should probably be discussed in an issue
first.[ ] This PR contains test cases, if meaningful.
- [ ] A reviewer from the core maintainer team has been assigned for this PR.
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Wasmtime GitHub notifications bot (Aug 09 2022 at 22:03):cfallin submitted PR review.
Wasmtime GitHub notifications bot (Aug 10 2022 at 17:02):cfallin merged PR #4616.
Last updated: Dec 23 2024 at 12:05 UTC