Deduplicate target emission helpers (#139)

include/numsim_codegen/code_emit/linear_algebra_emitter.h

@@ -190,6 +190,19 @@ class ArmadilloLinearAlgebraEmitter final : public LinearAlgebraEmitter {
   return eigen_linear_algebra_emitter();
 }
 
+// Include-gating predicate (#139): does the EMITTED body actually use `la`'s
+// backend? Keyed on the emitter's usage marker so the include decision tracks
+// the emitted code, not a re-derived coupling predicate (PR #83 round-2 #4) —
+// gating on a predicate could diverge from what was emitted (e.g. a future
+// pass-synthesized coupling) → a missing header for code that uses it. Shared
+// by every target that gates a linalg include on `body`; pass the SAME `la`
+// that drove emission so they cannot disagree.
+[[nodiscard]] inline auto uses_linear_algebra(std::string const &body,
+                                              LinearAlgebraEmitter const &la)
+    -> bool {
+  return body.find(la.usage_marker()) != std::string::npos;
+}
+
 } // namespace numsim::codegen
 
 #endif // NUMSIM_CODEGEN_LINEAR_ALGEBRA_EMITTER_H

include/numsim_codegen/code_emit/spectral_decompose_emit.h

@@ -20,6 +20,16 @@ namespace numsim::codegen {
 inline constexpr std::string_view spectral_runtime_qualifier =
     "numsim::codegen::rt::";
 
+// Include-gating predicate (#139): does the EMITTED body call into the
+// spectral runtime? Keyed on `spectral_runtime_qualifier` (shared with the
+// emitters, see above) so the `#include <numsim_codegen/runtime/spectral.h>`
+// decision tracks actual emitted usage — shared by every target that gates
+// the spectral-runtime include.
+[[nodiscard]] inline auto uses_spectral_runtime(std::string const &body)
+    -> bool {
+  return body.find(spectral_runtime_qualifier) != std::string::npos;
+}
+
 // Emit (once per distinct tensor argument) the shared spectral decomposition
 // that the eigenvalue / eigenprojection / eigenvector emitters read from, and
 // return the temporary's name. `arg` is the already-emitted C++ name of the

src/targets/moose_material.cpp

@@ -308,20 +308,14 @@ void emit_init_stateful_body(std::ostream &os, ConstitutiveModel const &model) {
 
 auto emit_source(ConstitutiveModel const &model, std::string const &app_name,
                  LinearAlgebraEmitter const &la) -> std::string {
-  // Emit the Layer-2 function first so the linalg-include decision tracks the
-  // ACTUAL emitted code (PR #83 round-2 #4): gating on a re-derived coupling
-  // predicate could diverge from what was emitted (e.g. a future pass-
-  // synthesized coupling) → a missing header for code that uses it. Keying on
-  // the emitter's usage marker cannot drift. The SAME `la` drives emission and
-  // the include (per-target, injected) so they cannot disagree.
+  // Emit the Layer-2 function first so both include decisions track the
+  // ACTUAL emitted code via the shared predicates (uses_linear_algebra /
+  // uses_spectral_runtime, #139) — keying on the emitters' markers cannot
+  // drift from what was emitted. The SAME `la` drives emission and the
+  // include (per-target, injected) so they cannot disagree.
   std::string const body = model.emit_compute_function(la);
-  bool const needs_la = body.find(la.usage_marker()) != std::string::npos;
-  // Spectral materials pull in the shipped tmech-only runtime helper. Keyed on
-  // actual emitted usage via the shared `spectral_runtime_qualifier` constant
-  // so it can't drift from what the emitters produced — same principle as the
-  // linalg marker.
-  bool const needs_spectral =
-      body.find(spectral_runtime_qualifier) != std::string::npos;
+  bool const needs_la = uses_linear_algebra(body, la);
+  bool const needs_spectral = uses_spectral_runtime(body);
 
   std::ostringstream os;
   os << "// Auto-generated by numsim-codegen. Do not edit.\n\n";