bcc: Fix segmentation fault for LLVM 15

When BCC is compiled with LLVM 15, running BCC tools will cause segfault.
The core dump reveals that the segfault is triggered by the calls to
`getPointerElementType()`. This is because LLVM is moving towards
`Opaque Pointer` ([0]). This commit follows the migration guide to fix
the issue.

  [0]: https://llvm.org/docs/OpaquePointers.html

Signed-off-by: Hengqi Chen <chenhengqi@outlook.com>

diff --git a/src/cc/bpf_module_rw_engine.cc b/src/cc/bpf_module_rw_engine.cc
index f1649880cb29a10e637d3a64687bc6a3117b6811..7ee3e111531e6d11ff4c105ffac65ff6a9b1683b 100644 (file)
--- a/src/cc/bpf_module_rw_engine.cc
+++ b/src/cc/bpf_module_rw_engine.cc
@@ -49,7 +49,12 @@ void BPFModule::cleanup_rw_engine() {
 
 static LoadInst *createLoad(IRBuilder<> &B, Value *addr, bool isVolatile = false)
 {
-#if LLVM_MAJOR_VERSION >= 14
+#if LLVM_MAJOR_VERSION >= 15
+  if (isa<AllocaInst>(addr))
+    return B.CreateLoad(dyn_cast<AllocaInst>(addr)->getAllocatedType(), addr, isVolatile);
+  else
+    return B.CreateLoad(addr->getType(), addr, isVolatile);
+#elif LLVM_MAJOR_VERSION >= 14
   return B.CreateLoad(addr->getType()->getPointerElementType(), addr, isVolatile);
 #else
   return B.CreateLoad(addr, isVolatile);
@@ -58,7 +63,12 @@ static LoadInst *createLoad(IRBuilder<> &B, Value *addr, bool isVolatile = false
 
 static Value *createInBoundsGEP(IRBuilder<> &B, Value *ptr, ArrayRef<Value *>idxlist)
 {
-#if LLVM_MAJOR_VERSION >= 14
+#if LLVM_MAJOR_VERSION >= 15
+  if (isa<GlobalValue>(ptr))
+    return B.CreateInBoundsGEP(dyn_cast<GlobalValue>(ptr)->getValueType(), ptr, idxlist);
+  else
+    return B.CreateInBoundsGEP(ptr->getType(), ptr, idxlist);
+#elif LLVM_MAJOR_VERSION >= 14
   return B.CreateInBoundsGEP(ptr->getType()->getScalarType()->getPointerElementType(),
                              ptr, idxlist);
 #else
@@ -116,7 +126,7 @@ static void finish_sscanf(IRBuilder<> &B, vector<Value *> *args, string *fmt,
   B.SetInsertPoint(label_false);
   // s = &s[nread];
   B.CreateStore(
-      createInBoundsGEP(B, createLoad(B, sptr), createLoad(B, nread, true)), sptr);
+      createInBoundsGEP(B, createLoad(B, sptr), {createLoad(B, nread, true)}), sptr);
 
   args->resize(2);
   fmt->clear();
@@ -400,10 +410,12 @@ int BPFModule::annotate() {
     table_names_[table.name] = id++;
     GlobalValue *gvar = mod_->getNamedValue(table.name);
     if (!gvar) continue;
-    if (PointerType *pt = dyn_cast<PointerType>(gvar->getType())) {
 #if LLVM_MAJOR_VERSION >= 15
-      StructType *st = dyn_cast<StructType>(pt->getPointerElementType());
+    {
+      Type *t = gvar->getValueType();
+      StructType *st = dyn_cast<StructType>(t);
 #else
+    if (PointerType *pt = dyn_cast<PointerType>(gvar->getType())) {
       StructType *st = dyn_cast<StructType>(pt->getElementType());
 #endif
       if (st) {