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authorStephen Hines <srhines@google.com>2014-12-01 14:51:49 -0800
committerStephen Hines <srhines@google.com>2014-12-02 16:08:10 -0800
commit37ed9c199ca639565f6ce88105f9e39e898d82d0 (patch)
tree8fb36d3910e3ee4c4e1b7422f4f017108efc52f5 /docs/BitCodeFormat.rst
parentd2327b22152ced7bc46dc629fc908959e8a52d03 (diff)
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Update aosp/master LLVM for rebase to r222494.
Change-Id: Ic787f5e0124df789bd26f3f24680f45e678eef2d
Diffstat (limited to 'docs/BitCodeFormat.rst')
-rw-r--r--docs/BitCodeFormat.rst26
1 files changed, 21 insertions, 5 deletions
diff --git a/docs/BitCodeFormat.rst b/docs/BitCodeFormat.rst
index fce1e37..34485b5 100644
--- a/docs/BitCodeFormat.rst
+++ b/docs/BitCodeFormat.rst
@@ -28,8 +28,9 @@ Unlike XML, the bitstream format is a binary encoding, and unlike XML it
provides a mechanism for the file to self-describe "abbreviations", which are
effectively size optimizations for the content.
-LLVM IR files may be optionally embedded into a `wrapper`_ structure that makes
-it easy to embed extra data along with LLVM IR files.
+LLVM IR files may be optionally embedded into a `wrapper`_ structure, or in a
+`native object file`_. Both of these mechanisms make it easy to embed extra
+data along with LLVM IR files.
This document first describes the LLVM bitstream format, describes the wrapper
format, then describes the record structure used by LLVM IR files.
@@ -460,6 +461,19 @@ to the start of the bitcode stream in the file, and the Size field is the size
in bytes of the stream. CPUType is a target-specific value that can be used to
encode the CPU of the target.
+.. _native object file:
+
+Native Object File Wrapper Format
+=================================
+
+Bitcode files for LLVM IR may also be wrapped in a native object file
+(i.e. ELF, COFF, Mach-O). The bitcode must be stored in a section of the
+object file named ``.llvmbc``. This wrapper format is useful for accommodating
+LTO in compilation pipelines where intermediate objects must be native object
+files which contain metadata in other sections.
+
+Not all tools support this format.
+
.. _encoding of LLVM IR:
LLVM IR Encoding
@@ -714,7 +728,7 @@ global variable. The operand fields are:
* *unnamed_addr*: If present and non-zero, indicates that the variable has
``unnamed_addr``
-.. _dllstorageclass:
+.. _bcdllstorageclass:
* *dllstorageclass*: If present, an encoding of the DLL storage class of this variable:
@@ -773,7 +787,8 @@ function. The operand fields are:
* *prefix*: If non-zero, the value index of the prefix data for this function,
plus 1.
-* *dllstorageclass*: An encoding of the `dllstorageclass`_ of this function
+* *dllstorageclass*: An encoding of the
+ :ref:`dllstorageclass<bcdllstorageclass>` of this function
MODULE_CODE_ALIAS Record
^^^^^^^^^^^^^^^^^^^^^^^^
@@ -791,7 +806,8 @@ fields are
* *visibility*: If present, an encoding of the `visibility`_ of the alias
-* *dllstorageclass*: If present, an encoding of the `dllstorageclass`_ of the alias
+* *dllstorageclass*: If present, an encoding of the
+ :ref:`dllstorageclass<bcdllstorageclass>` of the alias
MODULE_CODE_PURGEVALS Record
^^^^^^^^^^^^^^^^^^^^^^^^^^^^