Allow multiple arguments for delete()

Implements passing of multiple arguments to delete().

E.g. you can now do

@x[1] = 1;
@x[2] = 2;
@c = 5;
delete(@x[1], @x[2], @c);

instead of having to call delete() separately for each individual map
element.

CHANGELOG.md

@@ -17,6 +17,8 @@ and this project adheres to
   - [#3027](https://github.com/bpftrace/bpftrace/pull/3027)
 - Add LLVM 18 support
   - [#3051](https://github.com/bpftrace/bpftrace/pull/3051)
+- Add ability to call delete() with multiple arguments
+  - [#3046](https://github.com/bpftrace/bpftrace/pull/3046)
 #### Changed
 #### Deprecated
 #### Removed

man/adoc/bpftrace.adoc

@@ -2292,8 +2292,8 @@ Functions that are marked *async* are asynchronous which can lead to unexpected
 | Count how often this function is called.
 | Sync
 
-| <<map-functions-delete, `delete(mapkey k)`>>
-| Delete a single key from a map. For a single value map this deletes the only element. For an associative-array the key to delete has to be specified.
+| <<map-functions-delete, `delete(mapkey k, ...)`>>
+| Delete a single key from a map. For a single value map this deletes the only element. For an associative-array the key to delete has to be specified. Multiple arguments can be passed to delete many keys at once.
 | Sync
 
 | <<map-functions-hist, `hist(int64 n[, int k])`>>
@@ -2399,18 +2399,21 @@ i:s:10 {
 === delete
 
 .variants
-* `delete(mapkey k)`
+* `delete(mapkey k, ...)`
 
 Delete a single key from a map.
 For a single value map this deletes the only element.
 For an associative-array the key to delete has to be specified.
+Multiple arguments can be passed to delete many keys at once.
 
 ```
 k:dummy {
   @scalar = 1;
   @associative[1,2] = 1;
   delete(@scalar);
   delete(@associative[1,2]);
+  // alternatively, you can delete both at once
+  delete(@scalar, @associative[1,2]);
 
   delete(@associative); // error
 }

src/ast/passes/codegen_llvm.cpp

@@ -555,17 +555,18 @@ void CodegenLLVM::visit(Call &call)
     b_.CreateLifetimeEnd(key);
     expr_ = nullptr;
   } else if (call.func == "delete") {
-    auto &arg = *call.vargs->at(0);
-    auto &map = static_cast<Map &>(arg);
-    auto [key, scoped_key_deleter] = getMapKey(map);
-    if (!is_bpf_map_clearable(map_types_[map.ident])) {
-      // store zero instead of calling bpf_map_delete_elem()
-      AllocaInst *val = b_.CreateAllocaBPF(map.type, map.ident + "_zero");
-      b_.CreateStore(Constant::getNullValue(b_.GetType(map.type)), val);
-      b_.CreateMapUpdateElem(ctx_, map, key, val, call.loc);
-      b_.CreateLifetimeEnd(val);
-    } else {
-      b_.CreateMapDeleteElem(ctx_, map, key, call.loc);
+    for (const auto &arg : *call.vargs) {
+      auto &map = static_cast<Map &>(*arg);
+      auto [key, scoped_key_deleter] = getMapKey(map);
+      if (!is_bpf_map_clearable(map_types_[map.ident])) {
+        // store zero instead of calling bpf_map_delete_elem()
+        AllocaInst *val = b_.CreateAllocaBPF(map.type, map.ident + "_zero");
+        b_.CreateStore(Constant::getNullValue(b_.GetType(map.type)), val);
+        b_.CreateMapUpdateElem(ctx_, map, key, val, call.loc);
+        b_.CreateLifetimeEnd(val);
+      } else {
+        b_.CreateMapDeleteElem(ctx_, map, key, call.loc);
+      }
     }
     expr_ = nullptr;
   } else if (call.func == "str") {

src/ast/passes/semantic_analyser.cpp

@@ -606,12 +606,13 @@ void SemanticAnalyser::visit(Call &call)
     call.type = CreateStats(true);
   } else if (call.func == "delete") {
     check_assignment(call, false, false, false);
-    if (check_nargs(call, 1)) {
-      auto &arg = *call.vargs->at(0);
-      if (!arg.is_map)
-        LOG(ERROR, call.loc, err_) << "delete() expects a map to be provided";
+    if (check_varargs(call, 1, std::numeric_limits<size_t>::max())) {
+      for (const auto &arg : *call.vargs) {
+        if (!arg->is_map)
+          LOG(ERROR, arg->loc, err_)
+              << "delete() only expects maps to be provided";
+      }
     }
-
     call.type = CreateNone();
   } else if (call.func == "str") {
     if (check_varargs(call, 1, 2)) {

tests/runtime/basic

@@ -220,6 +220,12 @@ PROG BEGIN { @ = 1; @a[1] = 1; delete(@); delete(@a[1]); printf("ok\n"); exit();
 EXPECT ok
 TIMEOUT 1
 
+NAME delete multiple-map
+PROG BEGIN { @ = 1; @a[1] = 1; delete(@, @a[1]); exit(); }
+EXPECT_NONE @: 1
+EXPECT_NONE @a[1]: 1
+TIMEOUT 1
+
 NAME delete count-map
 PROG BEGIN { @ = count(); @a[1] = count(); delete(@); delete(@a[1]); exit(); }
 EXPECT @: 0

tests/semantic_analyser.cpp

@@ -538,13 +538,29 @@ TEST(semantic_analyser, call_stats)
 TEST(semantic_analyser, call_delete)
 {
   test("kprobe:f { @x = 1; delete(@x); }", 0);
+  test("kprobe:f { @x = 1; @y = 2; delete(@x, @y); }", 0);
+  test("kprobe:f { @x = 1; @y[5] = 5; delete(@x, @y[5]); }", 0);
   test("kprobe:f { delete(1); }", 1);
   test("kprobe:f { delete(); }", 1);
   test("kprobe:f { @y = delete(@x); }", 1);
   test("kprobe:f { $y = delete(@x); }", 1);
   test("kprobe:f { @[delete(@x)] = 1; }", 1);
   test("kprobe:f { @x = 1; if(delete(@x)) { 123 } }", 10);
   test("kprobe:f { @x = 1; delete(@x) ? 0 : 1; }", 10);
+
+  test_error("kprobe:f { @x = 1; @y[5] = 5; delete(@x, @y); }", R"(
+stdin:1:42-44: ERROR: Argument mismatch for @y: trying to access with arguments: [] when map expects arguments: [unsigned int64]
+kprobe:f { @x = 1; @y[5] = 5; delete(@x, @y); }
+                                         ~~
+)");
+  test_error("kprobe:f { @x = 1; $y = 2; $c = 3; delete(@x, $y, $c); }", R"(
+stdin:1:47-49: ERROR: delete() only expects maps to be provided
+kprobe:f { @x = 1; $y = 2; $c = 3; delete(@x, $y, $c); }
+                                              ~~
+stdin:1:51-53: ERROR: delete() only expects maps to be provided
+kprobe:f { @x = 1; $y = 2; $c = 3; delete(@x, $y, $c); }
+                                                  ~~
+)");
 }
 
 TEST(semantic_analyser, call_exit)