Index: docs/LangRef.rst =================================================================== --- docs/LangRef.rst +++ docs/LangRef.rst @@ -579,7 +579,9 @@ case they don't have an initializer. Either global variable definitions or declarations may have an explicit section -to be placed in and may have an optional explicit alignment specified. +to be placed in and may have an optional explicit alignment specified. A +mismatch between section information in the variable declaration and its +definition is undefined behavior. A variable may be defined as a global ``constant``, which indicates that the contents of the variable will **never** be modified (enabling better @@ -622,6 +624,12 @@ Additionally, the global can placed in a comdat if the target has the necessary support. +External declarations may have an explicit section specified. Section +information is retained in LLVM IR for targets that make use of this +information. Attaching section information to an external declaration is an +assertion that its definition is located in the specified section. If the +definition is located in a different section, the behavior is undefined. + By default, global initializers are optimized by assuming that global variables defined within the module are not modified from their initial values before the start of the global initializer. This is