MC: Support COFF image-relative MCSymbolRefs
Add support for the COFF relocation types IMAGE_REL_I386_DIR32NB and
IMAGE_REL_AMD64_ADDR32NB for 32- and 64-bit respectively. These are
similar to normal 4-byte relocations except that they do not include
the base address of the image.
Image-relative relocations are used for debug information (32-bit) and
SEH unwind tables (64-bit).
A new MCSymbolRef variant called 'VK_COFF_IMGREL32' is introduced to
specify such relocations. For AT&T assembly, this variant can be accessed
using the symbol suffix '@imgrel'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179240 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/Extensions.rst b/docs/Extensions.rst
new file mode 100644
index 0000000..062804a
--- /dev/null
+++ b/docs/Extensions.rst
@@ -0,0 +1,39 @@
+===============
+LLVM Extensions
+===============
+
+.. contents::
+ :local:
+ :depth: 1
+
+.. toctree::
+ :hidden:
+
+Introduction
+============
+
+This document describes extensions to tools and formats LLVM seeks compatibility
+with.
+
+Machine-specific Assembly Syntax
+================================
+
+X86/COFF-Dependent
+------------------
+
+The following additional relocation type is supported:
+
+**@IMGREL** (AT&T syntax only) generates an image-relative relocation that
+corresponds to the COFF relocation types ``IMAGE_REL_I386_DIR32NB`` (32-bit) or
+``IMAGE_REL_AMD64_ADDR32NB`` (64-bit).
+
+.. code-block:: gas
+
+ .text
+ fun:
+ mov foo@IMGREL(%ebx, %ecx, 4), %eax
+
+ .section .pdata
+ .long fun@IMGREL
+ .long (fun@imgrel + 0x3F)
+ .long $unwind$fun@imgrel
diff --git a/docs/index.rst b/docs/index.rst
index c3bb808..6b182da 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -160,6 +160,7 @@
ExtendingLLVM
HowToSetUpLLVMStyleRTTI
ProgrammersManual
+ Extensions
:doc:`LLVM Language Reference Manual <LangRef>`
Defines the LLVM intermediate representation and the assembly form of the
@@ -172,6 +173,9 @@
Introduction to the general layout of the LLVM sourcebase, important classes
and APIs, and some tips & tricks.
+:doc:`Extensions`
+ LLVM-specific extensions to tools and formats LLVM seeks compatibility with.
+
:doc:`CommandLine`
Provides information on using the command line parsing library.