[clang-ifs] Clang Interface Stubs, first version (second landing attempt).

Authored by plotfi on Jun 20 2019, 9:59 AM.


[clang-ifs] Clang Interface Stubs, first version (second landing attempt).

This change reverts r363649; effectively re-landing r363626. At this point
clang::Index::CodegenNameGeneratorImpl has been refactored into
clang::AST::ASTNameGenerator. This makes it so that the previous circular link
dependency no longer exists, fixing the previous share lib
(-DBUILD_SHARED_LIBS=ON) build issue which was the reason for r363649.

Clang interface stubs (previously referred to as clang-ifsos) is a new frontend
action in clang that allows the generation of stub files that contain mangled
name info that can be used to produce a stub library. These stub libraries can
be useful for breaking up build dependencies and controlling access to a
library's internal symbols. Generation of these stubs can be invoked by:

clang -fvisibility=<visibility> -emit-interface-stubs \

-interface-stub-version=<interface format>

Notice that -fvisibility (along with use of visibility attributes) can be used
to control what symbols get generated. Currently the interface format is
experimental but there are a wide range of possibilities here.

Currently clang-ifs produces .ifs files that can be thought of as analogous to
object (.o) files, but just for the mangled symbol info. In a subsequent patch
I intend to add support for merging the .ifs files into one .ifs/.ifso file
that can be the input to something like llvm-elfabi to produce something like a
.so file or .dll (but without any of the code, just symbols).

Differential Revision: https://reviews.llvm.org/D60974

llvm-svn: 363948


plotfiJun 20 2019, 9:59 AM
Differential Revision
D60974: Clang IFSO driver action.
rGaa10f050447d: [CodeGen] Fix formatting and comments (NFC)