CMake: Make most target symbols hidden by default
Summary:
For builds with LLVM_BUILD_LLVM_DYLIB=ON and BUILD_SHARED_LIBS=OFF
this change makes all symbols in the target specific libraries hidden
by default.
A new macro called LLVM_EXTERNAL_VISIBILITY has been added to mark symbols in these
libraries public, which is mainly needed for the definitions of the
LLVMInitialize* functions.
This patch reduces the number of public symbols in libLLVM.so by about
25%. This should improve load times for the dynamic library and also
make abi checker tools, like abidiff require less memory when analyzing
libLLVM.so
One side-effect of this change is that for builds with
LLVM_BUILD_LLVM_DYLIB=ON and LLVM_LINK_LLVM_DYLIB=ON some unittests that
access symbols that are no longer public will need to be statically linked.
Before and after public symbol counts (using gcc 8.2.1, ld.bfd 2.31.1):
nm before/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
36221
nm after/libLLVM-9svn.so | grep ' [A-Zuvw] ' | wc -l
26278
Reviewers: chandlerc, beanz, mgorny, rnk, hans
Reviewed By: rnk, hans
Subscribers: Jim, hiraditya, michaelplatings, chapuni, jholewinski, arsenm, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, nhaehnle, javed.absar, sbc100, jgravelle-google, aheejin, kbarton, fedor.sergeev, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, zzheng, edward-jones, mgrang, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, PkmX, jocewei, kristina, jsji, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D54439
llvm-svn: 362990
diff --git a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
index 0881bf8..8711d67 100644
--- a/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
+++ b/llvm/lib/Target/Hexagon/AsmParser/HexagonAsmParser.cpp
@@ -813,10 +813,10 @@
return true;
}
-// extern "C" void LLVMInitializeHexagonAsmLexer();
+// extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonAsmLexer();
/// Force static initialization.
-extern "C" void LLVMInitializeHexagonAsmParser() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonAsmParser() {
RegisterMCAsmParser<HexagonAsmParser> X(getTheHexagonTarget());
}
diff --git a/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp b/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
index 99e3ee8..2519857 100644
--- a/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
+++ b/llvm/lib/Target/Hexagon/Disassembler/HexagonDisassembler.cpp
@@ -158,7 +158,7 @@
return new HexagonDisassembler(STI, Ctx, T.createMCInstrInfo());
}
-extern "C" void LLVMInitializeHexagonDisassembler() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonDisassembler() {
TargetRegistry::RegisterMCDisassembler(getTheHexagonTarget(),
createHexagonDisassembler);
}
diff --git a/llvm/lib/Target/Hexagon/HexagonAsmPrinter.cpp b/llvm/lib/Target/Hexagon/HexagonAsmPrinter.cpp
index b07d156..3f8d5ea 100644
--- a/llvm/lib/Target/Hexagon/HexagonAsmPrinter.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonAsmPrinter.cpp
@@ -771,6 +771,6 @@
OutStreamer->EmitInstruction(MCB, getSubtargetInfo());
}
-extern "C" void LLVMInitializeHexagonAsmPrinter() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonAsmPrinter() {
RegisterAsmPrinter<HexagonAsmPrinter> X(getTheHexagonTarget());
}
diff --git a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
index 80b8480..8656f97 100644
--- a/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonTargetMachine.cpp
@@ -180,7 +180,7 @@
return *RM;
}
-extern "C" void LLVMInitializeHexagonTarget() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonTarget() {
// Register the target.
RegisterTargetMachine<HexagonTargetMachine> X(getTheHexagonTarget());
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
index 9c50b25..59a6299 100644
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
@@ -456,7 +456,7 @@
}
// Force static initialization.
-extern "C" void LLVMInitializeHexagonTargetMC() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonTargetMC() {
// Register the MC asm info.
RegisterMCAsmInfoFn X(getTheHexagonTarget(), createHexagonMCAsmInfo);
diff --git a/llvm/lib/Target/Hexagon/TargetInfo/HexagonTargetInfo.cpp b/llvm/lib/Target/Hexagon/TargetInfo/HexagonTargetInfo.cpp
index d77b235..48770be 100644
--- a/llvm/lib/Target/Hexagon/TargetInfo/HexagonTargetInfo.cpp
+++ b/llvm/lib/Target/Hexagon/TargetInfo/HexagonTargetInfo.cpp
@@ -15,7 +15,7 @@
return TheHexagonTarget;
}
-extern "C" void LLVMInitializeHexagonTargetInfo() {
+extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeHexagonTargetInfo() {
RegisterTarget<Triple::hexagon, /*HasJIT=*/true> X(
getTheHexagonTarget(), "hexagon", "Hexagon", "Hexagon");
}