diff options
Diffstat (limited to 'llvm/docs')
| -rw-r--r-- | llvm/docs/LangRef.rst | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst index 8e9d4204dbb..519fe2069ef 100644 --- a/llvm/docs/LangRef.rst +++ b/llvm/docs/LangRef.rst @@ -596,7 +596,8 @@ Syntax:: [@<GlobalVarName> =] [Linkage] [Visibility] [DLLStorageClass] [ThreadLocal] [unnamed_addr] [AddrSpace] [ExternallyInitialized] <global | constant> <Type> [<InitializerConstant>] - [, section "name"] [, align <Alignment>] + [, section "name"] [, comdat [($name)]] + [, align <Alignment>] For example, the following defines a global in a numbered address space with an initializer, section, and alignment: @@ -681,7 +682,7 @@ Syntax:: define [linkage] [visibility] [DLLStorageClass] [cconv] [ret attrs] <ResultType> @<FunctionName> ([argument list]) - [unnamed_addr] [fn Attrs] [section "name"] [comdat $<ComdatName>] + [unnamed_addr] [fn Attrs] [section "name"] [comdat [($name)]] [align N] [gc] [prefix Constant] [prologue Constant] { ... } The argument list is a comma seperated sequence of arguments where each @@ -775,12 +776,21 @@ the COMDAT key's section is the largest: .. code-block:: llvm $foo = comdat largest - @foo = global i32 2, comdat $foo + @foo = global i32 2, comdat($foo) - define void @bar() comdat $foo { + define void @bar() comdat($foo) { ret void } +As a syntactic sugar the ``$name`` can be omitted if the name is the same as +the global name: + +.. code-block:: llvm + + $foo = comdat any + @foo = global i32 2, comdat + + In a COFF object file, this will create a COMDAT section with selection kind ``IMAGE_COMDAT_SELECT_LARGEST`` containing the contents of the ``@foo`` symbol and another COMDAT section with selection kind @@ -803,8 +813,8 @@ For example: $foo = comdat any $bar = comdat any - @g1 = global i32 42, section "sec", comdat $foo - @g2 = global i32 42, section "sec", comdat $bar + @g1 = global i32 42, section "sec", comdat($foo) + @g2 = global i32 42, section "sec", comdat($bar) From the object file perspective, this requires the creation of two sections with the same name. This is necessary because both globals belong to different |
