enums: Symbolize in maps

This commit teaches bpftrace to symbolize enums when used in mapsfor the default human-readable output. We leave JSON output alone for now in case machines are parsing the current output format. This should make it easier to aggregate by enums without having to go thru the extra step of consulting enum definitions.
bpftrace · Oct 29, 2024 · 9ac33c7 · 9ac33c7
1 parent 96497cf
commit 9ac33c7
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Showing 4 changed files with 103 additions and 27 deletions.
diff --git a/.github/include/aot_skip.txt b/.github/include/aot_skip.txt
@@ -77,8 +77,20 @@ aot.json-output.scalar
 aot.json-output.scalar_str
 aot.json-output.stats
 aot.other.if_compare_and_print_string
+# Enum metadata is not being serialized
+aot.other.no symbolize enum after arithmetic
+# Enum metadata is not being serialized
+aot.other.no symbolize enum after arithmetic mixed
 aot.other.per_cpu_map_arithmetic
 aot.other.per_cpu_map_avg_if
+# Enum metadata is not being serialized
+aot.other.symbolize enum in map key
+# Enum metadata is not being serialized
+aot.other.symbolize enum in map value
+# Enum metadata is not being serialized
+aot.other.symbolize enum in tuple map key
+# Enum metadata is not being serialized
+aot.other.symbolize enum in tuple map value
 aot.probe.fentry
 aot.probe.fentry args
 aot.probe.fentry args as a pointer

diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -58,6 +58,8 @@ and this project adheres to
   - [#3300](https://github.com/bpftrace/bpftrace/pull/3300)
 - Change `delete` API to accept a map and key as separate args
   - [#3472](https://github.com/bpftrace/bpftrace/pull/3472)
+- Symbolize enums when used in maps
+  - [#3539](https://github.com/bpftrace/bpftrace/pull/3539)
 #### Deprecated
 #### Removed
 - Remove the `-dd` CLI option

diff --git a/src/output.cpp b/src/output.cpp
@@ -341,33 +341,68 @@ std::string Output::value_to_str(BPFtrace &bpftrace,
       return std::to_string(read_data<uint64_t>(value.data()) / div);
     }
     case Type::integer: {
-      auto sign = type.IsSigned();
-      switch (type.GetIntBitWidth()) {
-          // clang-format off
-        case 64:
-          if (sign)
-            return std::to_string(reduce_value<int64_t>(value, nvalues) / static_cast<int64_t>(div));
-          return std::to_string(reduce_value<uint64_t>(value, nvalues) / div);
-        case 32:
-          if (sign)
-            return std::to_string(
-                reduce_value<int32_t>(value, nvalues) / static_cast<int32_t>(div));
-          return std::to_string(reduce_value<uint32_t>(value, nvalues) / div);
-        case 16:
-          if (sign)
-            return std::to_string(
-                reduce_value<int16_t>(value, nvalues) / static_cast<int16_t>(div));
-          return std::to_string(reduce_value<uint16_t>(value, nvalues) / div);
-        case 8:
-          if (sign)
-            return std::to_string(
-                reduce_value<int8_t>(value, nvalues) / static_cast<int8_t>(div));
-          return std::to_string(reduce_value<uint8_t>(value, nvalues) / div);
-          // clang-format on
-        default:
-          LOG(BUG) << "value_to_str: Invalid int bitwidth: "
-                   << type.GetIntBitWidth() << "provided";
-          return {};
+      if (type.IsEnumTy() && div == 1) {
+        assert(!is_per_cpu);
+
+        auto data = value.data();
+        auto enum_name = type.GetName();
+        uint64_t enum_val;
+        switch (type.GetIntBitWidth()) {
+          case 64:
+            enum_val = read_data<uint64_t>(data);
+            break;
+          case 32:
+            enum_val = read_data<uint32_t>(data);
+            break;
+          case 16:
+            enum_val = read_data<uint16_t>(data);
+            break;
+          case 8:
+            enum_val = read_data<uint8_t>(data);
+            break;
+          default:
+            LOG(BUG) << "value_to_str: Invalid int bitwidth: "
+                     << type.GetIntBitWidth() << "provided";
+            return {};
+        }
+
+        if (bpftrace.enum_defs_.contains(enum_name) &&
+            bpftrace.enum_defs_[enum_name].contains(enum_val)) {
+          return bpftrace.enum_defs_[enum_name][enum_val];
+        } else {
+          // Fall back to something comprehensible in case user somehow
+          // tricked the type system into accepting an invalid enum.
+          return std::to_string(enum_val);
+        }
+      } else {
+        auto sign = type.IsSigned();
+        switch (type.GetIntBitWidth()) {
+            // clang-format off
+          case 64:
+            if (sign)
+              return std::to_string(reduce_value<int64_t>(value, nvalues) / static_cast<int64_t>(div));
+            return std::to_string(reduce_value<uint64_t>(value, nvalues) / div);
+          case 32:
+            if (sign)
+              return std::to_string(
+                  reduce_value<int32_t>(value, nvalues) / static_cast<int32_t>(div));
+            return std::to_string(reduce_value<uint32_t>(value, nvalues) / div);
+          case 16:
+            if (sign)
+              return std::to_string(
+                  reduce_value<int16_t>(value, nvalues) / static_cast<int16_t>(div));
+            return std::to_string(reduce_value<uint16_t>(value, nvalues) / div);
+          case 8:
+            if (sign)
+              return std::to_string(
+                  reduce_value<int8_t>(value, nvalues) / static_cast<int8_t>(div));
+            return std::to_string(reduce_value<uint8_t>(value, nvalues) / div);
+            // clang-format on
+          default:
+            LOG(BUG) << "value_to_str: Invalid int bitwidth: "
+                     << type.GetIntBitWidth() << "provided";
+            return {};
+        }
       }
     }
     case Type::sum_t: {

diff --git a/tests/runtime/other b/tests/runtime/other
@@ -279,3 +279,30 @@ NAME dry run empty output
 RUN {{BPFTRACE}} --dry-run -e 'BEGIN { printf("hello\n"); @ = 0; }'
 EXPECT_NONE hello
 EXPECT_NONE @: 0
+
+NAME symbolize enum in map key
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @[ONE] = 11; @[TWO] = 22; @m[ONE] = 333; exit(); }
+EXPECT @[ONE]: 11
+EXPECT @[TWO]: 22
+EXPECT @m[ONE]: 333
+
+NAME symbolize enum in tuple map key
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @[ONE,TWO,ONE] = -1; exit(); }
+EXPECT @[ONE, TWO, ONE]: -1
+
+NAME symbolize enum in map value
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @ = ONE; exit(); }
+EXPECT @: ONE
+
+NAME symbolize enum in tuple map value
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @ = (ONE, TWO); exit(); }
+EXPECT @: (ONE, TWO)
+
+NAME no symbolize enum after arithmetic
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @[ONE+1] = TWO-1; exit(); }
+EXPECT @[2]: 1
+
+NAME no symbolize enum after arithmetic mixed
+PROG enum { ONE = 1, TWO = 2 }; BEGIN { @[ONE+1] = TWO-1; @[ONE] = ONE; exit(); }
+EXPECT @[2]: 1
+EXPECT @[1]: 1