feat(callgraph): C/C++ explicit type inference engines by shivasurya · Pull Request #673 · shivasurya/code-pathfinder

shivasurya · 2026-05-02T15:48:55Z

Summary

Adds the explicit type-tracking foundation for C/C++ call-graph resolution.

graph/callgraph/resolution/c_types.go — CTypeInferenceEngine, CFunctionScope, CVariableBinding. Tracks return types and per-function variable scopes drawn directly from source declarations.
graph/callgraph/resolution/cpp_types.go — CppTypeInferenceEngine embeds the C engine and adds class method / class field indices, plus auto handling.

TypeInfo contract

Source	Confidence	Used for
`declaration`	1.0	Explicit types from source — return types, variable decls, class members
`unresolved_auto`	0.0	C++ `auto x = ...` placeholders awaiting Phase 2 deduction

Design notes

Embedding: CppTypeInferenceEngine embeds CTypeInferenceEngine by value, so every C-engine method (ExtractReturnType, GetScope, GetVariable, etc.) is callable on the C++ engine. The embedded Registry field aliases the C++ registry's CModuleRegistry facet so updates propagate.
Reassignment: each variable name keeps a slice of bindings; GetVariable returns the latest. GetAllBindings exposes the history for future flow analysis.
auto detection: exact equality on \"auto\". Modifiers like auto* and auto& are concrete types and keep full confidence — they survive the override branch and route through the C engine unchanged.
Void returns: explicitly dropped at registration so void functions never pollute downstream lookups (which gate on GetReturnType != nil).
Thread safety: four sync.RWMutex instances guard Scopes, ReturnTypes, ClassMethods, ClassFields. Snapshot accessors (GetAllReturnTypes, GetAllScopes) return defensive copies.
Lazy scope creation: ExtractVariableType creates the scope on first use; callers do not need to call AddScope before the first variable.

Test plan

go build ./...
go test ./... — full suite green (25 packages)
go test -race ./graph/callgraph/resolution/... — clean
go vet ./...
golangci-lint run ./graph/callgraph/resolution/ — 0 issues
Coverage on changed lines: c_types.go 100%, cpp_types.go 100%
Spec test cases covered: NewC*Engine, ExtractReturnType (success + void), AddReturnType, ExtractVariableType (basic + reassignment), GetScope miss, AddScope, concurrent access (-race), embedded methods, RegisterClassMethod (success + void/empty drops + redeclaration), RegisterClassField (success + empty drops), auto zero-confidence, auto*/auto& exact-match, complex C types (pointer/const/struct), complex C++ types (templates / refs / nested templates).

Stacked on

shiva/cpp-module-registry (#672)

safedep · 2026-05-02T15:48:59Z

SafeDep Report Summary

No dependency changes detected. Nothing to scan.

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github-actions · 2026-05-02T15:49:29Z

Code Pathfinder Security Scan

No security issues detected.

Metric	Value
Files Scanned	4
Rules	205

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codecov · 2026-05-02T15:51:34Z

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.26%. Comparing base (ee277fb) to head (1fc411c).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #673      +/-   ##
==========================================
+ Coverage   85.18%   85.26%   +0.07%     
==========================================
  Files         180      182       +2     
  Lines       26237    26399     +162     
==========================================
+ Hits        22351    22508     +157     
- Misses       3024     3028       +4     
- Partials      862      863       +1

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shivasurya · 2026-05-03T13:15:00Z

This stack of pull requests is managed by Graphite. Learn more about stacking.

shivasurya · 2026-05-03T13:15:49Z

Merge activity

May 3, 1:15 PM UTC: A user started a stack merge that includes this pull request via Graphite.
May 3, 1:25 PM UTC: Graphite rebased this pull request as part of a merge.
May 3, 1:26 PM UTC: @shivasurya merged this pull request with Graphite.

Add CTypeInferenceEngine and CppTypeInferenceEngine under the resolution package. The engines index types that appear verbatim in C/C++ source — function return types, variable declarations, class method return types, and class field types — with Confidence=1.0 and Source="declaration". No inference, deduction, or propagation; later phases layer those on top. Highlights: - Function-scoped variable bindings track reassignment history; the latest binding wins on lookup. - C++ engine embeds the C engine by value so callers can use ExtractReturnType / GetScope / GetVariable uniformly. - C++ `auto` is recognised by exact match and stored with Confidence=0.0, Source="unresolved_auto" so resolvers skip it until Phase 2 deduces a concrete type. - Thread-safe via two RWMutex pairs on the C engine and two additional pairs for class-method and class-field maps; verified under `go test -race`. Sets up the typed receiver lookups consumed by PR-07 (C call graph) and PR-08 (C++ call graph). Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

## Summary Adds `BuildCCallGraph` — a four-pass algorithm that produces a `*core.CallGraph` for C projects, ready to merge into the unified graph alongside Python/Go. | Pass | Purpose | |---|---| | 1 | Index every C `function_definition` under `\"<relpath>::<name>\"` and ensure the FQN is also in `registry.FunctionIndex` | | 2 | Register explicit return types (skipping `void`) and emit `ParameterSymbol` entries for every named parameter | | 3 | Walk parser-emitted edges (`function_definition → call_expression`) to extract one `CallSiteInternal` per call — no second AST traversal | | 4 | Resolve targets in a definition-preferring order, then emit edges and `CallSite` records | ### Resolution order (Pass 4) 1. **Same-file definition** — common case (helper in same `.c`); deterministic and independent of include state. 2. **Global definition** — scan `registry.FunctionIndex[name]` for an FQN whose call-graph entry is a definition. Handles cross-`.c` calls. 3. **Same-file declaration** — accept a forward declaration when no definition exists project-wide. 4. **Declaration reachable through `#include`** — last resort so externs handed off to another translation unit still surface as edges. Calls that don't match any source produce a `CallSite{Resolved: false, FailureReason: \"external_or_unresolved\"}` — stdlib calls (`printf`, `malloc`) and unknown function pointers remain visible to rule writers without polluting the edge set. ### Design notes - **Edges from the parser**: every `parseCCallExpression` adds an edge from the enclosing function to the call node. The builder walks `OutgoingEdges` of each indexed function instead of doing byte-range containment, keeping Pass 3 deterministic and trivially testable. - **Definition vs declaration**: the parser sets `Metadata[\"is_declaration\"]=true` on prototype/extern decls. `isDeclaration()` reads that key with a typed assertion so non-declaration nodes (no metadata) fall through correctly. - **Recursion**: self-edges (`process → process`) are emitted as-is; the call graph already deduplicates via `AddEdge`. - **Static functions**: same FQN-by-file mechanism — file-scope statics in different `.c` files map to disjoint FQNs. - **Unique FunctionIndex entries**: Pass 1 dedupes against the registry's existing `FunctionIndex` so calling `BuildCCallGraph` after `BuildCModuleRegistry` is idempotent. ## Test plan - [x] `go build ./...` - [x] `go test ./...` — full suite green - [x] `go vet ./...` - [x] `golangci-lint run ./graph/callgraph/builder/` — 0 issues - [x] Coverage on `c_builder.go` lines: ~89.6% - [x] Spec scenarios covered: - Single-file `main()` → `add()` edge - Cross-file `.c` definition preferred over `.h` declaration - Header declaration via `#include` fallback - `printf` (stdlib) recorded as `Resolved:false` with failure reason - Recursive self-call - Same name in two `.c` files (file-scope statics) - Type engine populated; `void` returns dropped - Parameters indexed (anonymous params skipped) - Declarations skipped from Pass 2 type extraction - Merges cleanly into an empty unified graph - Non-C nodes ignored (mixed-language safety) - Anonymous / missing-file functions filtered - Empty-target call_expression produces no edge and no recorded site - Cross-`.c` global lookup works without an `#include` - Same-file forward declaration accepted when no definition exists ## Stacked on `shiva/cpp-type-inference` (#673)

shivasurya added enhancement New feature or request go Pull requests that update go code labels May 2, 2026

shivasurya self-assigned this May 2, 2026

shivasurya added enhancement New feature or request go Pull requests that update go code labels May 2, 2026

shivasurya changed the base branch from shiva/cpp-module-registry to graphite-base/673 May 3, 2026 13:23

shivasurya changed the base branch from graphite-base/673 to main May 3, 2026 13:24

shivasurya force-pushed the shiva/cpp-type-inference branch from 47d63d3 to 1fc411c Compare May 3, 2026 13:25

shivasurya merged commit d3ea40b into main May 3, 2026
6 checks passed

shivasurya deleted the shiva/cpp-type-inference branch May 3, 2026 13:26

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feat(callgraph): C/C++ explicit type inference engines#673

feat(callgraph): C/C++ explicit type inference engines#673
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shiva/cpp-type-inference

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shivasurya commented May 2, 2026

Summary

TypeInfo contract

Design notes

Test plan

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