From fdbf1bd9f1bdec32384eda47f419d895d11a1c50 Mon Sep 17 00:00:00 2001
From: XingYuShuai <1150775134@qq.com>
Date: Wed, 15 May 2024 14:42:27 +0800
Subject: [PATCH] [LICM] Solve runtime error caused by the signal function.

Using the option enable-signal to control whether to solve the
runtime error caused by the signal function when lto is turned on.
---
 llvm/cmake/modules/HandleLLVMOptions.cmake    |  8 ++++
 llvm/lib/Transforms/Scalar/LICM.cpp           | 47 +++++++++++++++++++
 .../Transforms/LICM/signal-before-loop-2.ll   | 25 ++++++++++
 .../Transforms/LICM/signal-before-loop.ll     | 25 ++++++++++
 llvm/test/lit.site.cfg.py.in                  |  1 +
 5 files changed, 106 insertions(+)
 create mode 100644 llvm/test/Transforms/LICM/signal-before-loop-2.ll
 create mode 100644 llvm/test/Transforms/LICM/signal-before-loop.ll

diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index b8e9dbe29d88..8be5d4ba52c2 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -120,6 +120,14 @@ else()
   set(LLVM_ENABLE_AUTOTUNER 0)
 endif()
 
+option(LLVM_BUILD_FOR_COMMON "" ON)
+if(LLVM_BUILD_FOR_COMMON)
+  set(LLVM_BUILD_FOR_COMMON 1)
+  add_definitions( -DBUILD_FOR_COMMON )
+else()
+  set(LLVM_BUILD_FOR_COMMON 0)
+endif()
+
 if(LLVM_ENABLE_EXPENSIVE_CHECKS)
   add_compile_definitions(EXPENSIVE_CHECKS)
 
diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index f8fab03f151d..2feec759f240 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -44,6 +44,9 @@
 #include "llvm/Analysis/AliasSetTracker.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CaptureTracking.h"
+#ifdef BUILD_FOR_COMMON
+#include "llvm/Analysis/CFG.h"
+#endif // BUILD_FOR_COMMON
 #include "llvm/Analysis/GuardUtils.h"
 #include "llvm/Analysis/LazyBlockFrequencyInfo.h"
 #include "llvm/Analysis/Loads.h"
@@ -122,6 +125,13 @@ static cl::opt<bool>
     SingleThread("licm-force-thread-model-single", cl::Hidden, cl::init(false),
                  cl::desc("Force thread model single in LICM pass"));
 
+#ifdef BUILD_FOR_COMMON
+static cl::opt<bool> DisableMovStoreInsOutsideOfLoopInSigFun(
+  "disable-move-store-ins-outside-of-loop",
+    cl::Hidden, cl::init(true), cl::desc("Disable move store instruction"
+    "outside of loop in signal function."));
+#endif // BUILD_FOR_COMMON
+
 static cl::opt<uint32_t> MaxNumUsesTraversed(
     "licm-max-num-uses-traversed", cl::Hidden, cl::init(8),
     cl::desc("Max num uses visited for identifying load "
@@ -2075,8 +2085,45 @@ bool llvm::promoteLoopAccessesToScalars(
     for (Use &U : ASIV->uses()) {
       // Ignore instructions that are outside the loop.
       Instruction *UI = dyn_cast<Instruction>(U.getUser());
+ #if defined(BUILD_FOR_COMMON)
+      if (DisableMovStoreInsOutsideOfLoopInSigFun) {
+        if (!UI)
+          continue;
+
+        // In the following scenario, there will be a loop index store 
+        // instruction that is moved outside the loop and when the termination 
+        // loop is triggered by the signal function, the store instruction is not 
+        // executed.However, the function registered by the signal will read the
+        // data sored in the store instruction, so the data read is incorrect.
+        // Solution: Prevent the store instruction form going outside the loop.
+        // NOTE: The sys_signal function takes the same arguments and performs 
+        // the same task as signal. They all belong to glic.
+        if(StoreSafety == StoreSafe && !CurLoop->contains(UI)) {
+          if(LoadInst *NotCurLoopLoad = dyn_cast<LoadInst>(UI)) {
+            Function *NotCurLoopFun = UI->getParent()->getParent();
+            for (Use &UseFun : NotCurLoopFun->uses()) {
+            CallInst *Call = dyn_cast<CallInst>(UseFun.getUser());
+            if (Call && Call->getCalledFunction() &&
+                (Call->getCalledFunction()->getName() == "__sysv_signal" ||
+                 Call->getCalledFunction()->getName() == "signal") &&
+                isPotentiallyReachable(Call->getParent(),
+                                       CurLoop->getLoopPreheader(),NULL,DT,
+                                       LI))
+              return false;
+            }
+          }
+        }
+
+        if (!CurLoop->contains(UI))
+          continue;
+      } else {
+        if (!UI || !CurLoop->contains(UI))
+          continue;
+      }
+#else
       if (!UI || !CurLoop->contains(UI))
         continue;
+#endif // BUILD_FOR_COMMON
 
       // If there is an non-load/store instruction in the loop, we can't promote
       // it.
diff --git a/llvm/test/Transforms/LICM/signal-before-loop-2.ll b/llvm/test/Transforms/LICM/signal-before-loop-2.ll
new file mode 100644
index 000000000000..da878c6c691b
--- /dev/null
+++ b/llvm/test/Transforms/LICM/signal-before-loop-2.ll
@@ -0,0 +1,25 @@
+; REQUIRES: enable_build_for_common
+; RUN:opt -disable-move-store-ins-outside-of-loop=true -S < %s | FileCheck %s 
+
+@Run_Index = external global i64
+
+declare ptr @signal(ptr)
+
+define void @report() {
+entry:
+  %0 = load i64, ptr @Run_Index, align 8
+  unreachable
+}
+
+define i32 @main() {
+if.end:
+  %call.i4 = call ptr @signal(ptr @report)
+  br label %for.cond
+
+; CHECK-LABEL: for.cond
+; CHECK: store
+for.cond:
+  %0 = load i64, ptr @Run_Index, align 8
+  store i64 %0, ptr @Run_Index, align 8
+  br label %for.cond
+}
diff --git a/llvm/test/Transforms/LICM/signal-before-loop.ll b/llvm/test/Transforms/LICM/signal-before-loop.ll
new file mode 100644
index 000000000000..cfae4e87db56
--- /dev/null
+++ b/llvm/test/Transforms/LICM/signal-before-loop.ll
@@ -0,0 +1,25 @@
+; REQUIRES: enable_build_for_common
+; RUN:opt -disable-move-store-ins-outside-of-loop=true -S < %s | FileCheck %s 
+
+@Run_Index = external global i64
+
+declare ptr @__sysv_signal(ptr)
+
+define void @report() {
+entry:
+  %0 = load i64, ptr @Run_Index, align 8
+  unreachable
+}
+
+define i32 @main() {
+if.end:
+  %call.i4 = call ptr @__sysv_signal(ptr @report)
+  br label %for.cond
+
+; CHECK-LABEL: for.cond
+; CHECK: store
+for.cond:
+  %0 = load i64, ptr @Run_Index, align 8
+  store i64 %0, ptr @Run_Index, align 8
+  br label %for.cond
+}
diff --git a/llvm/test/lit.site.cfg.py.in b/llvm/test/lit.site.cfg.py.in
index 0e9396e3b014..20c1ecca1d43 100644
--- a/llvm/test/lit.site.cfg.py.in
+++ b/llvm/test/lit.site.cfg.py.in
@@ -63,6 +63,7 @@ config.dxil_tests = @LLVM_INCLUDE_DXIL_TESTS@
 config.have_llvm_driver = @LLVM_TOOL_LLVM_DRIVER_BUILD@
 config.use_classic_flang = @LLVM_ENABLE_CLASSIC_FLANG@
 config.enable_enable_autotuner = @LLVM_ENABLE_AUTOTUNER@
+config.enable_build_for_common = @LLVM_BUILD_FOR_COMMON@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
-- 
2.38.1.windows.1

