Replace MCTargetOptionsCommandFlags.inc and CommandFlags.inc by runtime registration

MCTargetOptionsCommandFlags.inc and CommandFlags.inc are headers which contain
cl::opt with static storage.
These headers are meant to be incuded by tools to make it easier to parametrize
codegen/mc.

However, these headers are also included in at least two libraries: lldCommon
and handle-llvm. As a result, when creating DYLIB, clang-cpp holds a reference
to the options, and lldCommon holds another reference. Linking the two in a
single executable, as zig does[0], results in a double registration.

This patch explores an other approach: the .inc files are moved to regular
files, and the registration happens on-demand through static declaration of
options in the constructor of a static object.

[0] https://bugzilla.redhat.com/show_bug.cgi?id=1756977#c5

Differential Revision: https://reviews.llvm.org/D75579

1 files changed, 5 insertions, 3 deletions

diff --git a/llvm/tools/llvm-mca/llvm-mca.cpp b/llvm/tools/llvm-mca/llvm-mca.cpp
index 06c1ce9..9f3bf41 100644
--- a/llvm/tools/llvm-mca/llvm-mca.cpp
+++ b/llvm/tools/llvm-mca/llvm-mca.cpp
@@ -39,7 +39,7 @@
 #include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
 #include "llvm/MC/MCSubtargetInfo.h"
-#include "llvm/MC/MCTargetOptionsCommandFlags.inc"
+#include "llvm/MC/MCTargetOptionsCommandFlags.h"
 #include "llvm/MCA/CodeEmitter.h"
 #include "llvm/MCA/Context.h"
 #include "llvm/MCA/InstrBuilder.h"
@@ -62,6 +62,8 @@
 
 using namespace llvm;
 
+static mc::RegisterMCTargetOptionsFlags MOF;
+
 static cl::OptionCategory ToolOptions("Tool Options");
 static cl::OptionCategory ViewOptions("View Options");
 
@@ -353,7 +355,7 @@ int main(int argc, char **argv) {
   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
   assert(MRI && "Unable to create target register info!");
 
-  MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
+  MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
   std::unique_ptr<MCAsmInfo> MAI(
       TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
   assert(MAI && "Unable to create target asm info!");
@@ -443,7 +445,7 @@ int main(int argc, char **argv) {
       TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx));
 
   std::unique_ptr<MCAsmBackend> MAB(TheTarget->createMCAsmBackend(
-      *STI, *MRI, InitMCTargetOptionsFromFlags()));
+      *STI, *MRI, mc::InitMCTargetOptionsFromFlags()));
 
   for (const std::unique_ptr<mca::CodeRegion> &Region : Regions) {
     // Skip empty code regions.