It is mandatory to specify a comdat in order to receive comdat semantics
for a symbol. We were previously getting this wrong in -function-sections
mode; linker-weak symbols were being emitted in a selectany comdat. This
change causes such symbols to use a noduplicates comdat instead, fixing
the inconsistency.
Also correct an inaccuracy in the docs.
Differential Revision: http://reviews.llvm.org/D10828
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241103
91177308-0d34-0410-b5e6-
96231b3b80d8
COMDAT groups and COMDATs, at the object file level, are represented by
sections.
-Note that certain IR constructs like global variables and functions may create
-COMDATs in the object file in addition to any which are specified using COMDAT
-IR. This arises, for example, when a global variable has linkonce_odr linkage.
+Note that certain IR constructs like global variables and functions may
+create COMDATs in the object file in addition to any which are specified using
+COMDAT IR. This arises when the code generator is configured to emit globals
+in individual sections (e.g. when `-data-sections` or `-function-sections`
+is supplied to `llc`).
.. _namedmetadatastructure:
} else {
return COFF::IMAGE_COMDAT_SELECT_ASSOCIATIVE;
}
- } else if (GV->isWeakForLinker()) {
- return COFF::IMAGE_COMDAT_SELECT_ANY;
}
return 0;
}
--- /dev/null
+; RUN: llc -function-sections -o - %s | FileCheck %s
+
+target datalayout = "e-m:w-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-pc-windows-msvc"
+
+; CHECK: .section{{.*}}one_only
+define linkonce_odr void @foo() {
+ ret void
+}