Плеханов Даниил. Лабораторная работа 2, Вариант 2, LLVM IR.

llvm/compiler-course/llvm-ir/plekhanov_pass_pure/CMakeLists.txt

@@ -0,0 +1,14 @@
+set(Title "PureFunc")
+set(Student "Plekhanov_Daniil")
+set(Group "FIIT2")
+set(TARGET_NAME "${Title}_${Student}_${Group}_LLVM_IR")
+
+if (NOT WIN32 AND NOT CYGWIN)
+    file(GLOB_RECURSE SOURCES *.cpp *.h *.hpp)
+    add_llvm_pass_plugin(${TARGET_NAME} ${SOURCES}
+        DEPENDS
+        intrinsics_gen
+        BUILDTREE_ONLY
+    )
+    set(LLVM_TEST_DEPENDS ${TARGET_NAME} ${LLVM_TEST_DEPENDS} PARENT_SCOPE)
+endif()

llvm/compiler-course/llvm-ir/plekhanov_pass_pure/plekhanov.cpp

@@ -0,0 +1,36 @@
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/Passes/PassBuilder.h"
+#include "llvm/Passes/PassPlugin.h"
+
+using namespace llvm;
+
+namespace {
+struct PureFunctionPass : PassInfoMixin<PureFunctionPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &) {
+    for (auto &BB : F)
+      for (auto &I : BB)
+        if (I.mayReadOrWriteMemory())
+          return PreservedAnalyses::none();
+
+    F.addFnAttr("pure");
+    return PreservedAnalyses::none();
+  }
+
+  static bool isRequired() { return true; }
+};
+} // namespace
+extern "C" LLVM_ATTRIBUTE_WEAK PassPluginLibraryInfo llvmGetPassPluginInfo() {
+  return {LLVM_PLUGIN_API_VERSION, "PureFunctionPass", "0.1",
+          [](PassBuilder &PB) {
+            PB.registerPipelineParsingCallback(
+                [](StringRef Name, FunctionPassManager &FPM,
+                   ArrayRef<PassBuilder::PipelineElement>) {
+                  if (Name == "pure-func-pass") {
+                    FPM.addPass(PureFunctionPass{});
+                    return true;
+                  }
+                  return false;
+                });
+          }};
+}

llvm/test/compiler-course/plekhanov_pass_pure/test.ll

@@ -0,0 +1,66 @@
+; RUN: opt -load-pass-plugin %llvmshlibdir/PureFunc_Plekhanov_Daniil_FIIT2_LLVM_IR%pluginext\
+; RUN: -passes=pure-func-pass -S %s | FileCheck %s
+
+; int mul(int a, int b) { return a * b; }
+; CHECK: define i32 @_Z3muli(i32 %a, i32 %b) #0
+define i32 @_Z3muli(i32 %a, i32 %b) {
+entry:
+  %res = mul i32 %a, %b
+  ret i32 %res
+}
+
+@counter = global i32 0
+
+; void inc() { counter++; }
+; CHECK: define void @_Z3incv()
+; CHECK-NOT: #0
+define void @_Z3incv() {
+entry:
+  %val = load i32, ptr @counter
+  %inc = add i32 %val, 1
+  store i32 %inc, ptr @counter
+  ret void
+}
+
+; int identity(int x) { return x; }
+; CHECK: define i32 @_Z8identityi(i32 %x) #0
+define i32 @_Z8identityi(i32 %x) {
+entry:
+  ret i32 %x
+}
+
+declare void @external_impure()
+
+; void wrapper() { external_impure(); }
+; CHECK: define void @_Z7wrapperv()
+; CHECK-NOT: #0
+define void @_Z7wrapperv() {
+entry:
+  call void @external_impure()
+  ret void
+}
+
+; int abs(int x) { return x < 0 ? -x : x; }
+; CHECK: define i32 @_Z3absi(i32 %x) #0
+define i32 @_Z3absi(i32 %x) {
+entry:
+  %cmp = icmp slt i32 %x, 0
+  %neg = sub i32 0, %x
+  %res = select i1 %cmp, i32 %neg, i32 %x
+  ret i32 %res
+}
+
+@gptr = global ptr null
+
+; int read_gptr() { return ptrtoint(ptr @gptr to i32); }
+; CHECK: define i32 @_Z9read_gptrv()
+; CHECK-NOT: #0
+define i32 @_Z9read_gptrv() {
+entry:
+  %p = load ptr, ptr @gptr
+  %i = ptrtoint ptr %p to i32
+  ret i32 %i
+}
+
+; CHECK: attributes #0 = { "pure" }
+attributes #0 = { "pure" }