From 03bcd6ecc8e71af76a3ca1277adb4c2440265893 Mon Sep 17 00:00:00 2001 From: Bill Wendling Date: Thu, 1 Jul 2010 21:55:59 +0000 Subject: Implement the "linker_private_weak" linkage type. This will be used for Objective-C metadata types which should be marked as "weak", but which the linker will remove upon final linkage. However, this linkage isn't specific to Objective-C. For example, the "objc_msgSend_fixup_alloc" symbol is defined like this: .globl l_objc_msgSend_fixup_alloc .weak_definition l_objc_msgSend_fixup_alloc .section __DATA, __objc_msgrefs, coalesced .align 3 l_objc_msgSend_fixup_alloc: .quad _objc_msgSend_fixup .quad L_OBJC_METH_VAR_NAME_1 This is different from the "linker_private" linkage type, because it can't have the metadata defined with ".weak_definition". Currently only supported on Darwin platforms. llvm-svn: 107433 --- llvm/docs/LangRef.html | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) (limited to 'llvm/docs/LangRef.html') diff --git a/llvm/docs/LangRef.html b/llvm/docs/LangRef.html index 32f143a93ae..13be38fed43 100644 --- a/llvm/docs/LangRef.html +++ b/llvm/docs/LangRef.html @@ -24,6 +24,7 @@
  1. 'private' Linkage
  2. 'linker_private' Linkage
    3. +
  3. 'linker_private_weak' Linkage
  4. 'internal' Linkage
  5. 'available_externally' Linkage
  6. 'linkonce' Linkage
    7. @@ -546,20 +547,24 @@ define i32 @main() { ; i32()*
    private
    -
    Global values with private linkage are only directly accessible by objects - in the current module. In particular, linking code into a module with an - private global value may cause the private to be renamed as necessary to - avoid collisions. Because the symbol is private to the module, all - references can be updated. This doesn't show up in any symbol table in the - object file.
    +
    Global values with "private" linkage are only directly accessible + by objects in the current module. In particular, linking code into a + module with an private global value may cause the private to be renamed as + necessary to avoid collisions. Because the symbol is private to the + module, all references can be updated. This doesn't show up in any symbol + table in the object file.
    linker_private
    -
    Similar to private, but the symbol is passed through the assembler and - removed by the linker after evaluation. Note that (unlike private - symbols) linker_private symbols are subject to coalescing by the linker: - weak symbols get merged and redefinitions are rejected. However, unlike - normal strong symbols, they are removed by the linker from the final - linked image (executable or dynamic library).
    +
    Similar to private, but the symbol is passed through the + assembler and evaluated by the linker. Unlike normal strong symbols, they + are removed by the linker from the final linked image (executable or + dynamic library).
    + +
    linker_private_weak
    +
    Similar to "linker_private", but the symbol is weak. Note that + linker_private_weak symbols are subject to coalescing by the + linker. The symbols are removed by the linker from the final linked image + (executable or dynamic library).
    internal
    Similar to private, but the value shows as a local symbol @@ -623,8 +628,8 @@ define i32 @main() { ; i32()*
    weak_odr
    Some languages allow differing globals to be merged, such as two functions with different semantics. Other languages, such as C++, ensure - that only equivalent globals are ever merged (the "one definition rule" - - "ODR"). Such languages can use the linkonce_odr + that only equivalent globals are ever merged (the "one definition rule" + — "ODR"). Such languages can use the linkonce_odr and weak_odr linkage types to indicate that the global will only be merged with equivalent globals. These linkage types are otherwise the same as their non-odr versions.
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