Add sym and usym builtins

README.md

@@ -194,8 +194,10 @@ Variables:
 - `func` - Name of the function currently being traced
 
 Functions:
-- `quantize(int n)` - produce a log2 histogram of values of `n`
-- `count()` - count the number of times this function is called
-- `delete()` - delete the map element this is assigned to
-- `str(char *s)` - returns the string pointed to by `s`
-- `printf(char *fmt, ...)` - write to stdout
+- `quantize(int n)` - Produce a log2 histogram of values of `n`
+- `count()` - Count the number of times this function is called
+- `delete()` - Delete the map element this is assigned to
+- `str(char *s)` - Returns the string pointed to by `s`
+- `printf(char *fmt, ...)` - Write to stdout
+- `sym(void *p)` - Resolve kernel address
+- `usym(void *p)` - Resolve user space address (incomplete)

src/ast/codegen_llvm.cpp

@@ -160,6 +160,10 @@ void CodegenLLVM::visit(Call &call)
     b_.CreateProbeReadStr(buf, call.type.size, expr_);
     expr_ = buf;
   }
+  else if (call.func == "sym" || call.func == "usym")
+  {
+    call.vargs->front()->accept(*this);
+  }
   else if (call.func == "printf")
   {
     ArrayType *string_type = ArrayType::get(b_.getInt8Ty(), STRING_SIZE);

src/ast/semantic_analyser.cpp

@@ -119,16 +119,22 @@ void SemanticAnalyser::visit(Call &call)
     }
     call.type = SizedType(Type::del, 0);
   }
-  else if (call.func == "str") {
+  else if (call.func == "str" || call.func == "sym" || call.func == "usym") {
     if (nargs != 1) {
-      err_ << "str() should take 1 arguments (";
+      err_ << call.func << "() should take 1 arguments (";
       err_ << nargs << " provided)" << std::endl;
     }
     if (is_final_pass() && call.vargs->at(0)->type.type != Type::integer) {
-      err_ << "str() only supports integer arguments";
+      err_ << call.func << "() only supports integer arguments";
       err_ << " (" << call.vargs->at(0)->type.type << " provided)" << std::endl;
     }
-    call.type = SizedType(Type::string, STRING_SIZE);
+
+    if (call.func == "str")
+      call.type = SizedType(Type::string, STRING_SIZE);
+    else if (call.func == "sym")
+      call.type = SizedType(Type::sym, 8);
+    else if (call.func == "usym")
+      call.type = SizedType(Type::usym, 8);
   }
   else if (call.func == "printf") {
     if (call.map) {

tests/semantic_analyser.cpp

@@ -101,6 +101,23 @@ TEST(semantic_analyser, call_str)
   test("kprobe:f { str(arg0); }", 0);
   test("kprobe:f { @x = str(arg0); }", 0);
   test("kprobe:f { str(); }", 1);
+  test("kprobe:f { str(\"hello\"); }", 10);
+}
+
+TEST(semantic_analyser, call_sym)
+{
+  test("kprobe:f { sym(arg0); }", 0);
+  test("kprobe:f { @x = sym(arg0); }", 0);
+  test("kprobe:f { sym(); }", 1);
+  test("kprobe:f { sym(\"hello\"); }", 10);
+}
+
+TEST(semantic_analyser, call_usym)
+{
+  test("kprobe:f { usym(arg0); }", 0);
+  test("kprobe:f { @x = usym(arg0); }", 0);
+  test("kprobe:f { usym(); }", 1);
+  test("kprobe:f { usym(\"hello\"); }", 10);
 }
 
 TEST(semantic_analyser, map_reassignment)