[Polly][NewPM] Update pass registration for the LLVM plugin interface

[philip.pfaffe]

Summary

As of rL329273, LLVM has a mechanism to load new-pm plugins in opt. Use
this API in Polly.

[grosser]

Hi Philip,

I am not sure what this means. Is this something that can already be tested? Or is this tested by the change in test/lit.site.cfg.in?

Best,
Tobias

[philip.pfaffe]

The tests for this I added in a follow-up revision D45493, which, as you can see, is quite large. I wanted to keep the functional change here and the mechanical changes to the tests separate for better review.

So, this change here cannot be tested on its own.

[grosser]

OK. Then this LGTM.

Personally, I would add a minimal test cases that shows this works. But this is probably subjective. Feel free to add one or not.

[Meinersbur]

test/lit.site.cfg.in

47–50 ↗

(On Diff #141830)

Don't -load and -load-pass-plugin conflict? If the so is loaded twice into the address space, shoudn't some global symbols or cl::opt initializer clash?

[philip.pfaffe]

test/lit.site.cfg.in

47–50 ↗

(On Diff #141830)

They don't! That's the beauty of this.

Both mechanisms are built on top of DynamicLibrary, which guarantees that you can safely load the same shared library twice.

[Meinersbur]

test/lit.site.cfg.in

47–50 ↗

(On Diff #141830)

Cool, I didn't know that.

[philip.pfaffe]

Add a testcase.

polly/trunk/lib/Support/RegisterPasses.cpp

 #include "polly/ScopDetection.h"
 #include "polly/ScopInfo.h"
 #include "polly/Simplify.h"
 #include "polly/Support/DumpModulePass.h"
 #include "llvm/Analysis/CFGPrinter.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
 #include "llvm/Support/TargetSelect.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/IPO/PassManagerBuilder.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Vectorize.h"
 
 using namespace llvm;
 using namespace polly;
void RegisterPollyPasses(PassBuilder &PB) {
   PB.registerPipelineParsingCallback(parseScopPipeline);
   PB.registerParseTopLevelPipelineCallback(parseTopLevelPipeline);
 
   if (PassPosition == POSITION_BEFORE_VECTORIZER)
     PB.registerVectorizerStartEPCallback(buildDefaultPollyPipeline);
   // FIXME else Error?
 }
 } // namespace polly
+
+// Plugin Entrypoint:
+extern "C" ::llvm::PassPluginLibraryInfo LLVM_ATTRIBUTE_WEAK LLVM_PLUGIN_EXPORT
+llvmGetPassPluginInfo() {
+  return {LLVM_PLUGIN_API_VERSION, "Polly", LLVM_VERSION_STRING,
+          polly::RegisterPollyPasses};
+}

polly/trunk/test/Support/Plugins.ll

+; RUN: opt %loadPolly -passes='polly-prepare,scop(print<polly-ast>)' -S < %s \
+; RUN: | FileCheck %s
+
+; This testcase tests plugin registration. Check-lines below serve to verify
+; that the passes actually ran.
+
+; CHECK-LABEL: void @foo
+; CHECK-NEXT: entry:
+; CHECK-NEXT: br label %entry.split
+define void @foo() {
+entry:
+  ret void
+}

polly/trunk/test/lit.site.cfg.in

if config.link_polly_into_tools == '' or \
    config.link_polly_into_tools.lower() == 'n' or \
    config.link_polly_into_tools.lower() == 'no' or \
    config.link_polly_into_tools.lower() == 'off' or \
    config.link_polly_into_tools.lower() == 'false' or \
    config.link_polly_into_tools.lower() == 'notfound' or \
    config.link_polly_into_tools.lower() == 'link_polly_into_tools-notfound':
     config.substitutions.append(('%loadPolly', '-load '
                                  + config.polly_lib_dir + '/LLVMPolly@LLVM_SHLIBEXT@'
+                                 + ' -load-pass-plugin '
+                                 + config.polly_lib_dir + '/LLVMPolly@LLVM_SHLIBEXT@'
                                  + ' -polly-process-unprofitable '
                                  + ' -polly-remarks-minimal '
                                  + ' -polly-use-llvm-names '
                                  + ' -polly-import-jscop-dir=%S '
                                  + ' -polly-codegen-verify '
                                  ))
 else:
     config.substitutions.append(('%loadPolly', ''