Enable for-loops in multiple probes

For-loops in multiple probes are now supported without problems b/c
libbpf takes care of program relocations.

This reverts commit cdf9e9d and
re-enables a disabled runtime test for the feature.

CHANGELOG.md

@@ -13,6 +13,8 @@ and this project adheres to
   - [#3203](https://github.com/bpftrace/bpftrace/pull/3203)
 - Enable avg map reads in kernel space (implicit casting)
   - [#3268](https://github.com/bpftrace/bpftrace/pull/3268)
+- Enable for-loops in multiple probes
+  - [#3285](https://github.com/bpftrace/bpftrace/pull/3285)
 #### Changed
 - Stream output when printing maps
   - [#3264](https://github.com/bpftrace/bpftrace/pull/3264)

src/ast/passes/semantic_analyser.cpp

@@ -2073,13 +2073,6 @@ void SemanticAnalyser::visit(For &f)
    *     }
    */
 
-  if (scope_with_for_loop_.has_value() && *scope_with_for_loop_ != scope_) {
-    LOG(ERROR, f.loc, err_)
-        << "Currently, for-loops can be used only in a single probe.";
-  } else {
-    scope_with_for_loop_ = scope_;
-  }
-
   // Validate decl
   const auto &decl_name = f.decl->ident;
   if (variable_val_[scope_].find(decl_name) != variable_val_[scope_].end()) {

src/ast/passes/semantic_analyser.h

@@ -148,7 +148,6 @@ class SemanticAnalyser : public Visitor {
   bool has_end_probe_ = false;
   bool has_child_ = false;
   bool has_pos_param_ = false;
-  std::optional<ast::Scope *> scope_with_for_loop_ = std::nullopt;
 };
 
 Pass CreateSemanticPass();

tests/runtime/for

@@ -40,15 +40,13 @@ EXPECT (64, 128)
 EXPECT (65, 129)
 TIMEOUT 5
 
-# Disabled due to https://github.com/bpftrace/bpftrace/issues/3021
 NAME map multiple probes
 PROG BEGIN { @mapA[16] = 32; @mapA[17] = 33; @mapB[64] = 128; @mapB[65] = 129; for ($kv : @mapA) { print($kv); } exit(); } END { for ($kv : @mapB) { print($kv); } }
 EXPECT (16, 32)
 EXPECT (17, 33)
 EXPECT (64, 128)
 EXPECT (65, 129)
 TIMEOUT 5
-REQUIRES bash -c "exit 1"
 
 NAME map nested vals
 PROG BEGIN { @mapA[16] = 32; @mapB[64] = 128; @mapB[65] = 129; for ($kv : @mapA) { print($kv); for ($kv2 : @mapB) { print($kv2); } } exit(); }

tests/semantic_analyser.cpp

@@ -3769,20 +3769,6 @@ kprobe:f { @map[0] = 1; for ($kv : @map) { arg0 } }
 )");
 }
 
-TEST(semantic_analyser, for_loop_multiple_probes)
-{
-  test_error(R"(
-      BEGIN { @map[0] = 1 }
-      k:f1 { for ($kv : @map) { print($kv); } }
-      k:f2 { for ($kv : @map) { print($kv); } }
-  )",
-             R"(
-stdin:3:14-17: ERROR: Currently, for-loops can be used only in a single probe.
-      k:f2 { for ($kv : @map) { print($kv); } }
-             ~~~
-)");
-}
-
 TEST_F(semantic_analyser_btf, args_builtin_mixed_probes)
 {
   test_error("kfunc:func_1,tracepoint:sched:sched_one { args }", R"(