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llvm-project/llvm/test/CodeGen/WebAssembly/target-features-tls.ll

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[WebAssembly] Implement thread-local storage (local-exec model) Summary: Thread local variables are placed inside a `.tdata` segment. Their symbols are offsets from the start of the segment. The address of a thread local variable is computed as `__tls_base` + the offset from the start of the segment. `.tdata` segment is a passive segment and `memory.init` is used once per thread to initialize the thread local storage. `__tls_base` is a wasm global. Since each thread has its own wasm instance, it is effectively thread local. Currently, `__tls_base` must be initialized at thread startup, and so cannot be used with dynamic libraries. `__tls_base` is to be initialized with a new linker-synthesized function, `__wasm_init_tls`, which takes as an argument a block of memory to use as the storage for thread locals. It then initializes the block of memory and sets `__tls_base`. As `__wasm_init_tls` will handle the memory initialization, the memory does not have to be zeroed. To help allocating memory for thread-local storage, a new compiler intrinsic is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns the size of the thread-local storage for the current function. The expected usage is to run something like the following upon thread startup: __wasm_init_tls(malloc(__builtin_wasm_tls_size())); Reviewers: tlively, aheejin, kripken, sbc100 Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D64537 llvm-svn: 366272
2019-07-17 06:00:45 +08:00
; RUN: llc < %s -mattr=-bulk-memory | FileCheck %s --check-prefixes NO-BULK-MEM
; RUN: llc < %s -mattr=+bulk-memory | FileCheck %s --check-prefixes BULK-MEM
[WebAssembly] Merge used feature sets, update atomics linkage policy Summary: It does not currently make sense to use WebAssembly features in some functions but not others, so this CL adds an IR pass that takes the union of all used feature sets and applies it to each function in the module. This allows us to prevent atomics from being lowered away if some function has opted in to using them. When atomics is not enabled anywhere, we detect whether there exists any atomic operations or thread local storage that would be stripped and disallow linking with objects that contain atomics if and only if atomics or tls are stripped. When atomics is enabled, mark it as used but do not require it of other objects in the link. These changes allow libraries that do not use atomics to be built once and linked into both single-threaded and multithreaded binaries. Reviewers: aheejin, sbc100, dschuff Subscribers: jgravelle-google, hiraditya, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59625 llvm-svn: 357226
2019-03-29 08:14:01 +08:00
; Test that the target features section contains -atomics or +atomics
; for modules that have thread local storage in their source.
target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
target triple = "wasm32-unknown-unknown"
@foo = internal thread_local global i32 0
[WebAssembly] Implement thread-local storage (local-exec model) Summary: Thread local variables are placed inside a `.tdata` segment. Their symbols are offsets from the start of the segment. The address of a thread local variable is computed as `__tls_base` + the offset from the start of the segment. `.tdata` segment is a passive segment and `memory.init` is used once per thread to initialize the thread local storage. `__tls_base` is a wasm global. Since each thread has its own wasm instance, it is effectively thread local. Currently, `__tls_base` must be initialized at thread startup, and so cannot be used with dynamic libraries. `__tls_base` is to be initialized with a new linker-synthesized function, `__wasm_init_tls`, which takes as an argument a block of memory to use as the storage for thread locals. It then initializes the block of memory and sets `__tls_base`. As `__wasm_init_tls` will handle the memory initialization, the memory does not have to be zeroed. To help allocating memory for thread-local storage, a new compiler intrinsic is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns the size of the thread-local storage for the current function. The expected usage is to run something like the following upon thread startup: __wasm_init_tls(malloc(__builtin_wasm_tls_size())); Reviewers: tlively, aheejin, kripken, sbc100 Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D64537 llvm-svn: 366272
2019-07-17 06:00:45 +08:00
; -bulk-memory
; NO-BULK-MEM-LABEL: .custom_section.target_features,"",@
; NO-BULK-MEM-NEXT: .int8 1
; NO-BULK-MEM-NEXT: .int8 45
; NO-BULK-MEM-NEXT: .int8 7
; NO-BULK-MEM-NEXT: .ascii "atomics"
; NO-BULK-MEM-NEXT: .bss.foo,"",@
[WebAssembly] Merge used feature sets, update atomics linkage policy Summary: It does not currently make sense to use WebAssembly features in some functions but not others, so this CL adds an IR pass that takes the union of all used feature sets and applies it to each function in the module. This allows us to prevent atomics from being lowered away if some function has opted in to using them. When atomics is not enabled anywhere, we detect whether there exists any atomic operations or thread local storage that would be stripped and disallow linking with objects that contain atomics if and only if atomics or tls are stripped. When atomics is enabled, mark it as used but do not require it of other objects in the link. These changes allow libraries that do not use atomics to be built once and linked into both single-threaded and multithreaded binaries. Reviewers: aheejin, sbc100, dschuff Subscribers: jgravelle-google, hiraditya, sunfish, jfb, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D59625 llvm-svn: 357226
2019-03-29 08:14:01 +08:00
[WebAssembly] Implement thread-local storage (local-exec model) Summary: Thread local variables are placed inside a `.tdata` segment. Their symbols are offsets from the start of the segment. The address of a thread local variable is computed as `__tls_base` + the offset from the start of the segment. `.tdata` segment is a passive segment and `memory.init` is used once per thread to initialize the thread local storage. `__tls_base` is a wasm global. Since each thread has its own wasm instance, it is effectively thread local. Currently, `__tls_base` must be initialized at thread startup, and so cannot be used with dynamic libraries. `__tls_base` is to be initialized with a new linker-synthesized function, `__wasm_init_tls`, which takes as an argument a block of memory to use as the storage for thread locals. It then initializes the block of memory and sets `__tls_base`. As `__wasm_init_tls` will handle the memory initialization, the memory does not have to be zeroed. To help allocating memory for thread-local storage, a new compiler intrinsic is introduced: `__builtin_wasm_tls_size()`. This instrinsic function returns the size of the thread-local storage for the current function. The expected usage is to run something like the following upon thread startup: __wasm_init_tls(malloc(__builtin_wasm_tls_size())); Reviewers: tlively, aheejin, kripken, sbc100 Subscribers: dschuff, jgravelle-google, hiraditya, sunfish, jfb, cfe-commits, llvm-commits Tags: #clang, #llvm Differential Revision: https://reviews.llvm.org/D64537 llvm-svn: 366272
2019-07-17 06:00:45 +08:00
; +bulk-memory
; BULK-MEM-LABEL: .custom_section.target_features,"",@
; BULK-MEM-NEXT: .int8 1
; BULK-MEM-NEXT: .int8 43
; BULK-MEM-NEXT: .int8 11
; BULK-MEM-NEXT: .ascii "bulk-memory"
; BULK-MEM-NEXT: .tbss.foo,"",@