From 9477d577636bb7262aad0daf6fee1d1aa74b3d08 Mon Sep 17 00:00:00 2001 From: Yunzhong Gao Date: Thu, 5 Dec 2013 18:37:54 +0000 Subject: [PATCH] Document that dllexported symbols are preserved by optimization passes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@196523 91177308-0d34-0410-b5e6-96231b3b80d8 --- docs/LangRef.rst | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/docs/LangRef.rst b/docs/LangRef.rst index f7f83dba696..9adbea5e9ee 100644 --- a/docs/LangRef.rst +++ b/docs/LangRef.rst @@ -289,7 +289,9 @@ symbols from (to) DLLs (Dynamic Link Libraries). pointer to a pointer in a DLL, so that it can be referenced with the ``dllimport`` attribute. On Microsoft Windows targets, the pointer name is formed by combining ``__imp_`` and the function or variable - name. + name. Since this linkage exists for defining a dll interface, the + compiler, assembler and linker know it is externally referenced and + must refrain from deleting the symbol. It is illegal for a function *declaration* to have any linkage type other than ``external``, ``dllimport`` or ``extern_weak``. @@ -501,8 +503,8 @@ variables defined within the module are not modified from their initial values before the start of the global initializer. This is true even for variables potentially accessible from outside the module, including those with external linkage or appearing in -``@llvm.used``. This assumption may be suppressed by marking the -variable with ``externally_initialized``. +``@llvm.used`` or dllexported variables. This assumption may be suppressed +by marking the variable with ``externally_initialized``. An explicit alignment may be specified for a global, which must be a power of 2. If not present, or if the alignment is set to zero, the -- 2.34.1