Speed up Dmod_Mgr_IsSystemModule/IsLoaded/IsEnabled

[JohnAmadis]

Problem

Dmod_Mgr_IsSystemModule() checks a module against every built-in input API, running Dmod_ApiSignature_IsModule() on each one. In dmod-boot that is 351 entries, ~105–137k instructions per call.

Dmod_Mgr_IsLoaded() and Dmod_Mgr_IsEnabled() called it first. So every Dmod_IsModuleLoaded(), Dmod_IsModuleEnabled() and Dmod_LoadModuleByName() paid for this scan, even for an ordinary module that was already loaded.

dmdevfs calls these several times per configured driver. In dmod-boot that was ~750 calls, ~226 ms of the boot in Renode.

Changes

1. Check loaded modules first

Dmod_Mgr_IsLoaded() and Dmod_Mgr_IsEnabled() now look the module up in the context table first (Dmod_Context_Get()). They fall back to Dmod_Mgr_IsSystemModule() only if the module is not there.

The result is the same as before; only the order of the two checks changed:

• IsLoaded = loaded || system
• IsEnabled = (loaded && enabled) || system

2. List of system module names built once

Dmod_Initialize() now calls Dmod_Mgr_BuildSystemModuleList(). It collects the module names of the built-in APIs once, into a single allocation (names packed one after another). In dmod-boot that is 7 names, 44 bytes.

Dmod_Mgr_IsSystemModule() then only compares the given name with this list.

• The comparison is the same as in Dmod_ApiSignature_IsModule(): the module name of an API starts with the given name. Only signatures with the DMOD/DMBI/DMAL/DDIF prefixes count, as before.
• If Dmod_Initialize() was not called (e.g. in unit tests), the list is built on first use.
• Dmod_Deinitialize() frees it (Dmod_Mgr_FreeSystemModuleList()).
• If the list cannot be allocated, the built-in APIs are checked one by one as before.

Tests

• CI steps run locally (MODULE + SYSTEM build, x86_64):
  • the dmod_loader runs, including the non-existent module case;
  • dif_test and test_direct_access;
  • tests_dmod_manifest.
• All 32 gtest unit test binaries pass.
• New tests in tests_dmod_mgr (17/17 pass):
  • BuildSystemModuleList: the list can be built twice;
  • IsSystemModuleAfterFreeingList: the list is rebuilt after it has been freed;
  • IsSystemModuleForEveryBuiltinApi: every module named by a built-in API is still reported as a system module.

Measured on dmod-boot (Renode, STM32F746G-DISCO, virtual time)

	Before	Loaded modules first	+ name list
Dmod_Mgr_IsSystemModule calls during boot	~750	329	354
Time in Dmod_Mgr_IsSystemModule	~226 ms	~75 ms	0.4 ms (~560 instructions per call)
One GPIO pin configured	4.0 ms	2.6 ms	—
Shell prompt	2052 ms	1892 ms	1788 ms

• Building the list takes 0.8 ms, once, in Dmod_Initialize().
• No new errors in the boot log.

🤖 Generated with Claude Code

https://claude.ai/code/session_01V9XGvT9zLJVAagoEVhYh9T