Tags: google/emboss
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Drop redundant Known() guard when discriminant is provably Known (#257) The optimized switch block opens with const auto emboss_reserved_switch_discrim = \${discriminant}; if (!emboss_reserved_switch_discrim.Known()) return false; The Known() guard is a safety net: if reading the discriminant failed, Ok() must return false. But fields_in_dependency_order guarantees the discriminant field is validated earlier in Ok(), and for a non-conditional, non-virtual field of the current structure the earlier \`if (has_X().ValueOrDefault() && !X().Ok()) return false;\` already enforces X().Ok(). Past that point the Maybe<> wrapper around the field read is provably Known and the extra guard is dead code. _is_discriminant_provably_known recognizes the safe shape — a single-segment field_reference to a non-conditional non-virtual field in the current structure's field list — and removes the guard in that case. The detection is intentionally narrow; nested paths and computed discriminants keep the guard. One line saved per qualifying switch — minor on hosted targets, but on Thumb-2 and MicroBlaze this removes a load, a compare, and a conditional return per switch block, plus the constant-pool slot.
Extend switch matcher: disjunction, conjunction, single-entry demotion ( #256) PR 241's _get_switch_candidate only matched bare \`discrim == K\` equalities. Real protocol grammars express the same intent in many forms; this PR rewrites the matcher to recognize them all. _extract_switch_arms decomposes an existence_condition into a (discriminant, [(case_value, residual), ...]) tuple, handling: * Bare equality (\`tag == K\`) — one arm, no residual. * Disjunction of equalities on a shared discriminant (\`tag == A || tag == B || tag == C\`) — one arm per Ki, no residual. Common for tagged unions where several values share a payload. Combined with the identical-body coalescing already in place, this collapses to a single multi-label switch arm. * Conjunction with an equality (\`tag == K && other_predicate\`) — one arm carrying \`[other_predicate]\` as residual. Useful for nested guards like \`if outer_flag && tag == K\`. * Mixed shapes inside a disjunction: \`(tag == 0 && a) || (tag == 1 && b) || tag == 2\` — three arms with respective residuals \`[a]\`, \`[b]\`, \`[]\`. An arm with a residual emits the has_\${field}()-based check as its case body (the residual is folded into the existing accessor) — sound and lets the C++ compiler fold the case-pinned discriminant comparison via inlining. A demotion pass measures total arm-entries per group and falls back to ok_method_test when the count is below 2 — without this, a lone field like \`if outer && tag == K: xc\` would get wrapped in a one-case switch whose overhead (temporary, Known() guard, scope braces) exceeds the dedupe. This also fixes a latent bug introduced when render-dedup was added: the scoped discriminant render mutated subexpressions during the grouping pass, so groups that later got demoted would have left dead \`const auto = ...\` definitions in the emitted Ok(). The scoped render now happens at emit time, only for surviving groups. The benchmark schema gains a DisjunctionConditionals struct exercising three \`||\` chains (2, 3, 3 labels) and the benchmark TU gains a runtime test for it. Golden churn: many_conditionals.emb.h gains the new struct's output; condition.emb.h and virtual_field.emb.h shrink because several BasicConditional-style structs had a lone xc field that PR 241 was wrapping in a one-arm switch — demotion brings them back to the cheaper has_xc() check.
Render switch discriminant once per group; drop dead inner scope (#253) * Render switch discriminant once per group; drop dead inner scope The optimized Ok() switch-block code in _generate_optimized_ok_method_body was rendering each switch group's discriminant twice: once unscoped at grouping time to build the SWITCH: key, and again with the active ExpressionScope at emit time. Render it once with the scope and reuse the result. The result is stable for equivalent discriminants because ExpressionScope.add dedupes by inner rendered form, so it still works as a grouping key. The ok_method_switch_block template's \${inner_scope_definitions} placeholder was unused — the inner ExpressionScope it referenced had nothing added to it. Removed both, which also drops the blank line each switch block carried in the goldens. No behavioral change; purely compile-time cleanup. Golden churn limited to the blank-line removal in four files (one line per existing switch block). * Sort switch cases by value; coalesce identical-body cases (#254) Three composing changes to the optimized Ok() switch generator: 1. Case-label sort. Each switch arm's labels are sorted by the underlying integer/enum value before emit. _case_sort_key() returns the int for sorting. Sorted cases give older embedded GCCs (the ones shipped with microblaze-elf and many bare-metal arm-none-eabi toolchains) a better shot at emitting a dense jump table rather than an if-ladder. 2. Identical-body coalescing. Cases whose rendered body text is identical (same field set in the same order) are merged into a single arm with multiple \`case X:\` labels. The C++ compiler emits one body for the whole arm — a real text-size win once a later PR (disjunction matching) starts producing such pairs. 3. Multi-field per case. When two conditional fields share a discriminant + case value (\`if tag == 0: a\` and \`if tag == 0: b\`), they're now bundled into the same case arm rather than the second falling back to a separate if-statement. Each field's validation becomes one line of the case body. The ok_method_switch_case template becomes ok_method_switch_arm, taking pre-formatted \${case_labels} and \${case_body} strings. Single-label single-field arms render identically to the old template, so golden churn is limited to the f0_copy field in testdata/many_conditionals.emb folding into case 0 of the LargeConditionals switch.
Add clang-format to c++ backend (#262) * Format generated C++ headers with clang-format Apply Google-style clang-format to all generated .emb.h output, in both the bazel codegen path (emboss_codegen_cpp.main) and the standalone embossc driver. The clang-format binary path is resolved through the new compiler/back_end/cpp/clang_format_path module, which is the single seam to the underlying binary. The upstream version uses the clang-format PyPI package; downstream forks that cannot use the PyPI package can replace just clang_format_path.py and its BUILD entry with a shim returning an alternative path. * Regenerate build.json for new clang_format_path.py * Move clang_format import to module top in clang_format_path.py
Add scripts/regenerate_goldens.py for batch golden regeneration (#251) * Add scripts/regenerate_goldens.py for batch golden regeneration Mirrors the cpp_golden_test list in compiler/back_end/cpp/BUILD, invoking embossc on each input .emb file to regenerate the corresponding golden header. Makes generator changes (which usually require regenerating dozens of golden files) a one-command operation instead of a per-file dance. Also handles the testdata/imported_genfiles.emb genrule transform locally and cleans up afterward so the produced file doesn't collide with the bazel genrule on subsequent builds. * Note regenerate_goldens.py mirror in BUILD
Add scripts/regenerate_goldens.py for batch golden regeneration (#251) * Add scripts/regenerate_goldens.py for batch golden regeneration Mirrors the cpp_golden_test list in compiler/back_end/cpp/BUILD, invoking embossc on each input .emb file to regenerate the corresponding golden header. Makes generator changes (which usually require regenerating dozens of golden files) a one-command operation instead of a per-file dance. Also handles the testdata/imported_genfiles.emb genrule transform locally and cleans up afterward so the produced file doesn't collide with the bazel genrule on subsequent builds. * Note regenerate_goldens.py mirror in BUILD
Bump black from 24.8.0 to 26.3.1 in the pip group across 1 directory (#… …246) * Bump black from 24.8.0 to 26.3.1 in the pip group across 1 directory Bumps the pip group with 1 update in the / directory: [black](https://github.com/psf/black). Updates `black` from 24.8.0 to 26.3.1 - [Release notes](https://github.com/psf/black/releases) - [Changelog](https://github.com/psf/black/blob/main/CHANGES.md) - [Commits](psf/black@24.8.0...26.3.1) --- updated-dependencies: - dependency-name: black dependency-version: 26.3.1 dependency-type: direct:production ... Signed-off-by: dependabot[bot] <support@github.com> * build: Add missing dependencies for black 26.3.1 --------- Signed-off-by: dependabot[bot] <support@github.com> Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com> Co-authored-by: Aaron Webster <webstera@google.com>
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