Ivanov Nikita. Lab 2. Var 3.

llvm/labs/lab2/ivanov_nikita/CMakeLists.txt

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+
+set(PluginName AtikinLoopPass)
+add_compile_definitions(NAME=${PluginName})
+
+string(TOUPPER ${PluginName} PluginNameUpper)
+set(LLVM_${PluginNameUpper}_LINK_INTO_TOOLS ON)
+
+file(GLOB_RECURSE ALL_SOURCE_FILES *.cpp *.h)
+add_llvm_pass_plugin(${PluginName} 
+${ALL_SOURCE_FILES}     
+DEPENDS
+intrinsics_gen
+BUILDTREE_ONLY)
+
+target_link_libraries(${PluginName}
+  PUBLIC
+  LLVMSupport
+  LLVMCore
+  LLVMipo
+  LLVMPasses)
+
+set(LLVM_TEST_DEPENDS ${PluginName} ${LLVM_TEST_DEPENDS} PARENT_SCOPE)

llvm/labs/lab2/ivanov_nikita/ivanov.cpp

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+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
+
+using namespace llvm;
+
+class MyLoopPass : public PassInfoMixin<MyLoopPass> {
+public:
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM) {
+    auto *Ty = FunctionType::get(llvm::Type::getVoidTy(F.getContext()),
+                                 false); // get func type
+    auto *M = F.getParent();
+
+    auto LoopStartFunc =
+        M->getOrInsertFunction("loop_start", Ty); // create func start
+    auto LoopEndFunc =
+        M->getOrInsertFunction("loop_end", Ty); // create func end
+
+    auto &LI = FAM.getResult<LoopAnalysis>(F);
+
+    for (auto &L : LI) { // for by loop
+      auto *Preheader =
+          L->getLoopPreheader();           // get preheader block of the loop
+      auto *ExitBlock = L->getExitBlock(); // end exit block of the loop
+      IRBuilder<> Builder(Preheader->getTerminator()); // api for basic block
+
+      if (!Preheader)
+        continue;
+
+      Builder.CreateCall(LoopStartFunc); // paste loop_start
+
+      if (!ExitBlock)
+        continue;
+
+      Builder.SetInsertPoint(
+          ExitBlock->getFirstNonPHI()); // set pointer to exit block
+      Builder.CreateCall(LoopEndFunc);  // paste loop_start
+    }
+    return PreservedAnalyses::all();
+  }
+};
+
+/* New PM Registration */
+llvm::PassPluginLibraryInfo getAtikinLoopPassPluginInfo() {
+  return {LLVM_PLUGIN_API_VERSION, "AtikinLoopPass", LLVM_VERSION_STRING,
+          [](llvm::PassBuilder &PB) {
+            PB.registerPipelineParsingCallback(
+                [](llvm::StringRef Name, llvm::FunctionPassManager &PM,
+                   llvm::ArrayRef<llvm::PassBuilder::PipelineElement>) {
+                  if (Name == "ivanov-loop-pass") {
+                    PM.addPass(MyLoopPass());
+                    return true;
+                  }
+                  return false;
+                });
+          }};
+}
+
+extern "C" LLVM_ATTRIBUTE_WEAK ::llvm::PassPluginLibraryInfo
+llvmGetPassPluginInfo() {
+  return getAtikinLoopPassPluginInfo();
+}

llvm/test/lab2/ivanov_nikita/test.ll

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+; RUN: opt -passes=ivanov-loop-pass -S %s 2>&1 | FileCheck %s
+
+; void foo(int n, int m) {
+;     int c0;
+;     int c1;
+;     for (c0 = n; c0 > 0; c0--) {
+;         c1++;
+;     }
+; }
+
+define dso_local void @_Z3fooii(i32 noundef %n, i32 noundef %m) {
+entry:
+  %n.addr = alloca i32, align 4
+  %m.addr = alloca i32, align 4
+  %c0 = alloca i32, align 4
+  %c1 = alloca i32, align 4
+  store i32 %n, ptr %n.addr, align 4
+  store i32 %m, ptr %m.addr, align 4
+  %0 = load i32, ptr %n.addr, align 4
+  store i32 %0, ptr %c0, align 4
+; CHECK:    call void @loop_start()
+  br label %for.cond
+
+for.cond:
+  %1 = load i32, ptr %c0, align 4
+  %cmp = icmp sgt i32 %1, 0
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:
+  %2 = load i32, ptr %c1, align 4
+  %inc = add nsw i32 %2, 1
+  store i32 %inc, ptr %c1, align 4
+  br label %for.inc
+
+for.inc:
+  %3 = load i32, ptr %c0, align 4
+  %dec = add nsw i32 %3, -1
+  store i32 %dec, ptr %c0, align 4
+  br label %for.cond
+
+for.end:
+; CHECK:    call void @loop_end()
+  ret void
+}