3f34e1b883
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
34 lines
1.1 KiB
LLVM
34 lines
1.1 KiB
LLVM
; RUN: llc -filetype=obj %s -o - | obj2yaml | FileCheck %s
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target triple = "wasm32-unknown-unknown"
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; Weak external data reference
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@weak_external_data = extern_weak global i32, align 4
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; Weak function definition
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define weak hidden i32 @weak_function() local_unnamed_addr #0 {
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entry:
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%0 = load i32, i32* @weak_external_data, align 4
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ret i32 %0
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}
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; CHECK: - Type: IMPORT
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; CHECK-NEXT: Imports:
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; CHECK: - Module: env
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; CHECK-NEXT: Field: __linear_memory
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; CHECK: - Module: env
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; CHECK-NEXT: Field: __indirect_function_table
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; CHECK: SymbolTable:
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; CHECK-NEXT: - Index: 0
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; CHECK-NEXT: Kind: FUNCTION
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; CHECK-NEXT: Name: weak_function
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; CHECK-NEXT: Flags: [ BINDING_WEAK, VISIBILITY_HIDDEN ]
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; CHECK-NEXT: Function: 0
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; CHECK-NEXT: - Index: 1
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; CHECK-NEXT: Kind: DATA
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; CHECK-NEXT: Name: weak_external_data
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; CHECK-NEXT: Flags: [ BINDING_WEAK, UNDEFINED ]
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; CHECK-NEXT: ...
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