Fix WHS reporting

linker/slashkit/emit/metadata/timing_freq.py

@@ -33,9 +33,14 @@
 
 HW_BUILD_DIR_ENV_KEYS = ("SLASH_HW_BUILD_DIR", "slash_hw_build_dir")
 _FLOAT_RE = re.compile(r"[-+]?\d+(?:\.\d+)?")
+# Columns are separated by two or more spaces; the multi-word headings
+# ("TNS Failing Endpoints") use single spaces internally.
+_COLUMN_SPLIT_RE = re.compile(r"\s{2,}")
 
 
-def _find_design_timing_summary_row(report_text: str) -> Optional[list[float]]:
+def _find_design_timing_summary_row(
+    report_text: str,
+) -> Optional[tuple[list[str], list[float]]]:
     if not report_text:
         return None
 
@@ -56,6 +61,9 @@ def _find_design_timing_summary_row(report_text: str) -> Optional[list[float]]:
     if header_idx is None:
         return None
 
+    header = lines[header_idx].strip()
+    columns = [c for c in _COLUMN_SPLIT_RE.split(header) if c]
+
     for i in range(header_idx + 1, min(header_idx + 20, len(lines))):
         line = lines[i].strip()
         if not line:
@@ -64,16 +72,39 @@ def _find_design_timing_summary_row(report_text: str) -> Optional[list[float]]:
             continue
         values = [float(m.group(0)) for m in _FLOAT_RE.finditer(line)]
         if values:
-            return values
+            return columns, values
 
     return None
 
 
+def _column_value(
+    columns: list[str], values: list[float], name: str
+) -> Optional[float]:
+    # Index by heading rather than by offset. Vivado interleaves endpoint counts
+    # between the slack columns -- WNS, TNS, TNS Failing Endpoints, TNS Total
+    # Endpoints, WHS, THS, ... -- so WHS sits at offset 4, not the 2 that a
+    # WNS/TNS/WHS/THS reading of the table would suggest. Reading offset 2
+    # returned the failing-endpoint count as the hold slack, which silently
+    # disabled the whs >= 0 half of design_timing_met() (a count is never
+    # negative) and printed nonsense in the failure message.
+    if len(columns) != len(values):
+        return None
+    try:
+        return values[columns.index(name)]
+    except ValueError:
+        return None
+
+
 def extract_design_timing_slacks_ns(report_text: str) -> Optional[tuple[float, float]]:
-    values = _find_design_timing_summary_row(report_text)
-    if values is None or len(values) < 3:
+    row = _find_design_timing_summary_row(report_text)
+    if row is None:
+        return None
+    columns, values = row
+    wns_ns = _column_value(columns, values, "WNS(ns)")
+    whs_ns = _column_value(columns, values, "WHS(ns)")
+    if wns_ns is None or whs_ns is None:
         return None
-    return values[0], values[2]
+    return wns_ns, whs_ns
 
 
 def extract_design_wns_ns(report_text: str) -> Optional[float]:

linker/test/emit/metadata/test_timing_freq.py

@@ -23,6 +23,8 @@
 import textwrap
 from pathlib import Path
 
+import pytest
+
 from slashkit.emit.metadata import timing_freq
 
 
@@ -34,19 +36,21 @@ def _write_system_map(path: Path, clock_hz: int) -> None:
     )
 
 
-def _write_timing_report(path: Path, wns_ns: float) -> None:
-    # Minimal shape matching what extract_design_wns_ns() scans for: a
-    # "Design Timing Summary" section, a WNS(ns)/TNS(ns) header, then a data row
-    # whose first value is WNS and third is WHS.
+def _write_timing_report(path: Path, wns_ns: float, whs_ns: float = 0.100) -> None:
+    # The full column set Vivado emits, reproduced verbatim from a V80 static
+    # shell run. The endpoint-count columns interleaved between the slacks are
+    # the point: an abridged WNS/TNS/WHS/THS table puts WHS at offset 2 and lets
+    # an offset-based parser look correct while reading the wrong column off a
+    # real report.
     path.write_text(
         textwrap.dedent(
             f"""\
-            Design Timing Summary
-            ---------------------
+            | Design Timing Summary
+            | ---------------------
 
-              WNS(ns)      TNS(ns)  WHS(ns)  THS(ns)
-              -------      -------  -------  -------
-              {wns_ns:.3f}      0.000    0.100    0.000
+                WNS(ns)      TNS(ns)  TNS Failing Endpoints  TNS Total Endpoints      WHS(ns)      THS(ns)  THS Failing Endpoints  THS Total Endpoints     WPWS(ns)     TPWS(ns)  TPWS Failing Endpoints  TPWS Total Endpoints
+                -------      -------  ---------------------  -------------------      -------      -------  ---------------------  -------------------     --------     --------  ----------------------  --------------------
+                 {wns_ns:.3f}       -31.539                   2049              1704696        {whs_ns:.3f}        0.000                      0              1700856        0.000        0.000                       0                520312
             """
         ),
         encoding="utf-8",
@@ -146,3 +150,37 @@ def test_met_target_does_not_warn(tmp_path, capsys):
     )
 
     assert "target not met" not in capsys.readouterr().err
+
+
+def test_slacks_come_from_the_named_columns(tmp_path):
+    # WHS must be read from the WHS(ns) column, not from a fixed offset. On a
+    # real report offset 2 is "TNS Failing Endpoints", so an offset-based parser
+    # reports the failing-endpoint count as the hold slack.
+    report = tmp_path / "report_timing_proj.txt"
+    _write_timing_report(report, wns_ns=-0.030, whs_ns=0.000)
+
+    slacks = timing_freq.extract_design_timing_slacks_ns(
+        report.read_text(encoding="utf-8"))
+
+    assert slacks == (-0.030, 0.000)
+
+
+def test_hold_violation_fails_the_gate(tmp_path):
+    # A design that meets setup but violates hold must not pass. This is the
+    # case the offset bug hid: the count it returned instead of WHS is never
+    # negative, so the whs >= 0 check could never fire.
+    build_dir = tmp_path
+    report = build_dir / "report_timing_proj.txt"
+    _write_timing_report(report, wns_ns=0.500, whs_ns=-0.012)
+
+    assert timing_freq.extract_design_timing_slacks_ns(
+        report.read_text(encoding="utf-8")) == (0.500, -0.012)
+    assert not timing_freq.design_timing_met(0.500, -0.012)
+
+    with pytest.raises(RuntimeError, match="timing failed"):
+        timing_freq.require_static_shell_timing_or_confirm(
+            build_dir=build_dir,
+            project_name="proj",
+            ignore_failure=False,
+            noninteractive=True,
+        )