fixes: https://github.com/iovisor/bpftrace/issues/3

src/ast/codegen_llvm.cpp

@@ -302,6 +302,13 @@ void CodegenLLVM::visit(Call &call)
     call.vargs->front()->accept(*this);
     b_.CreateProbeReadStr(buf, call.type.size, expr_);
     expr_ = buf;
+  }
+   else if (call.func == "kaddr")
+  {
+    uint64_t addr;
+    auto &name = static_cast<String&>(*call.vargs->at(0)).str;
+    addr = bpftrace_.resolve_kname(name.c_str());
+    expr_ = b_.getInt64(addr);
   }
   else if (call.func == "join")
   {

src/ast/semantic_analyser.cpp

@@ -209,6 +209,14 @@ void SemanticAnalyser::visit(Call &call)
 
     call.type = SizedType(Type::integer, 8);
   }
+  else if (call.func == "kaddr") {
+    if (check_nargs(call, 1)) {
+      if (check_arg(call, Type::string, 0, true)) {
+         ;
+      }
+    }
+    call.type = SizedType(Type::integer, 8);
+  }
   else if (call.func == "printf") {
     check_assignment(call, false, false);
     if (check_varargs(call, 1, 7)) {

src/bpftrace.cpp

@@ -1117,6 +1117,41 @@ std::string BPFtrace::resolve_sym(uintptr_t addr, bool show_offset)
   return symbol.str();
 }
 
+uint64_t BPFtrace::resolve_kname(const char *name)
+{
+  uint64_t addr = 0;
+  std::string file_name = "/proc/kallsyms";
+
+  std::ifstream file(file_name);
+  if (file.fail())
+  {
+    std::cerr << strerror(errno) << ": " << file_name << std::endl;
+    return addr;
+  }
+
+  std::string line;
+
+  std::string search = "\\b( ";
+  search += name;
+  std::regex e (search + ")");
+  std::smatch match;
+
+  while (std::getline(file, line) && addr == 0)
+  {
+    auto found = std::regex_search (line, match, e);
+
+    if (found)
+    {
+      std::string first_word = line.substr(0, line.find(" "));
+      addr = std::stoull(first_word, 0, 16);
+    }
+  }
+
+  file.close();
+
+  return addr;
+}
+
 std::string BPFtrace::resolve_usym(uintptr_t addr, int pid, bool show_offset)
 {
   struct bcc_symbol sym;

src/bpftrace.h

@@ -37,6 +37,7 @@ public:
   std::string get_stack(uint64_t stackidpid, bool ustack, int indent=0);
   std::string resolve_sym(uintptr_t addr, bool show_offset=false);
   std::string resolve_usym(uintptr_t addr, int pid, bool show_offset=false);
+  uint64_t resolve_kname(const char *name);
   std::string resolve_name(uint64_t name_id);
   int pid_;
 

tests/codegen.cpp

@@ -1024,6 +1024,23 @@ attributes #1 = { argmemonly nounwind }
 )EXPECTED");
 }
 
+TEST(codegen, call_kaddr)
+{
+  test("kprobe:f { @x = kaddr(\"avenrun\") }",
+
+R"EXPECTED(; Function Attrs: nounwind
+declare i64 @llvm.bpf.pseudo(i64, i64) #0
+
+BDG run bpftrace_test, and copy-n-paste the '+' diff output here until bpftrace_test passes this test
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { argmemonly nounwind }
+)EXPECTED");
+}
+
 TEST(codegen, call_hist)
 {
   test("kprobe:f { @x = hist(pid) }",

tests/parser.cpp

@@ -299,6 +299,17 @@ TEST(Parser, call_unknown_function)
       "  call: myfunc\n");
 }
 
+TEST(Parser, call_kaddr)
+{
+  test("kprobe:f { @ = kaddr(\"avenrun\") }",
+      "Program\n"
+      " kprobe:f\n"
+      "  =\n"
+      "   map: @\n"
+      "   call: kaddr\n"
+      "    string: avenrun\n");
+}
+
 TEST(Parser, multiple_probes)
 {
   test("kprobe:sys_open { 1; } kretprobe:sys_open { 2; }",

tests/semantic_analyser.cpp

@@ -253,6 +253,14 @@ TEST(semantic_analyser, call_usym)
   test("kprobe:f { usym(\"hello\"); }", 10);
 }
 
+TEST(semantic_analyser, call_kaddr)
+{
+  test("kprobe:f { kaddr(\"avenrun\"); }", 0);
+  test("kprobe:f { @x = kaddr(\"avenrun\"); }", 0);
+  test("kprobe:f { kaddr(); }", 1);
+  test("kprobe:f { kaddr(123); }", 1);
+}
+
 TEST(semantic_analyser, call_reg)
 {
   test("kprobe:f { reg(\"ip\"); }", 0);