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Diffstat (limited to 'llvm/docs/LangRef.rst')
| -rw-r--r-- | llvm/docs/LangRef.rst | 30 |
1 files changed, 26 insertions, 4 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index 99a2ffa40d6..9d910568bd5 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -527,6 +527,24 @@ the alias is accessed. It will not have any effect in the aliasee. For platforms without linker support of ELF TLS model, the -femulated-tls flag can be used to generate GCC compatible emulated TLS code. +.. _runtime_preemption_model: + +Runtime Preemption Specifiers +----------------------------- + +Global variables, functions and aliases may have an optional runtime preemption +specifier. If a preemption specifier isn't given explicitly, then a +symbol is assumed to be ``dso_preemptable``. + +``dso_preemptable`` + Indicates that the function or variable may be replaced by a symbol from + outside the linkage unit at runtime. + +``dso_local`` + The compiler may assume that a function or variable marked as ``dso_local`` + will resolve to a symbol within the same linkage unit. Direct access will + be generated even if the definition is not within this compilation unit. + .. _namedtypes: Structure Types @@ -650,6 +668,7 @@ iterate over them as an array, alignment padding would break this iteration. The maximum alignment is ``1 << 29``. Globals can also have a :ref:`DLL storage class <dllstorageclass>`, +an optional :ref:`runtime preemption specifier <runtime_preemption_model>`, an optional :ref:`global attributes <glattrs>` and an optional list of attached :ref:`metadata <metadata>`. @@ -658,7 +677,8 @@ Variables and aliases can have a Syntax:: - @<GlobalVarName> = [Linkage] [Visibility] [DLLStorageClass] [ThreadLocal] + @<GlobalVarName> = [Linkage] [PreemptionSpecifier] [Visibility] + [DLLStorageClass] [ThreadLocal] [(unnamed_addr|local_unnamed_addr)] [AddrSpace] [ExternallyInitialized] <global | constant> <Type> [<InitializerConstant>] @@ -691,7 +711,8 @@ Functions --------- LLVM function definitions consist of the "``define``" keyword, an -optional :ref:`linkage type <linkage>`, an optional :ref:`visibility +optional :ref:`linkage type <linkage>`, an optional :ref:`runtime preemption +specifier <runtime_preemption_model>`, an optional :ref:`visibility style <visibility>`, an optional :ref:`DLL storage class <dllstorageclass>`, an optional :ref:`calling convention <callingconv>`, an optional ``unnamed_addr`` attribute, a return type, an optional @@ -750,7 +771,7 @@ not be significant within the module. Syntax:: - define [linkage] [visibility] [DLLStorageClass] + define [linkage] [PreemptionSpecifier] [visibility] [DLLStorageClass] [cconv] [ret attrs] <ResultType> @<FunctionName> ([argument list]) [(unnamed_addr|local_unnamed_addr)] [fn Attrs] [section "name"] @@ -777,12 +798,13 @@ Aliases have a name and an aliasee that is either a global value or a constant expression. Aliases may have an optional :ref:`linkage type <linkage>`, an optional +:ref:`runtime preemption specifier <runtime_preemption_model>`, an optional :ref:`visibility style <visibility>`, an optional :ref:`DLL storage class <dllstorageclass>` and an optional :ref:`tls model <tls_model>`. Syntax:: - @<Name> = [Linkage] [Visibility] [DLLStorageClass] [ThreadLocal] [(unnamed_addr|local_unnamed_addr)] alias <AliaseeTy>, <AliaseeTy>* @<Aliasee> + @<Name> = [Linkage] [PreemptionSpecifier] [Visibility] [DLLStorageClass] [ThreadLocal] [(unnamed_addr|local_unnamed_addr)] alias <AliaseeTy>, <AliaseeTy>* @<Aliasee> The linkage must be one of ``private``, ``internal``, ``linkonce``, ``weak``, ``linkonce_odr``, ``weak_odr``, ``external``. Note that some system linkers |
