Mesa (main): isaspec: Add bitfield size assertions

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Module: Mesa
Branch: main
Commit: e08d152d68cd192b0c68d19c1228c06bb9166433
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=e08d152d68cd192b0c68d19c1228c06bb9166433

Author: Rob Clark <robdclark at chromium.org>
Date:   Mon Oct 11 11:50:03 2021 -0700

isaspec: Add bitfield size assertions

Signed-off-by: Rob Clark <robdclark at chromium.org>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13353>

---

 src/compiler/isaspec/encode.py | 25 ++++++++++++++++++++++---
 1 file changed, 22 insertions(+), 3 deletions(-)

diff --git a/src/compiler/isaspec/encode.py b/src/compiler/isaspec/encode.py
index 9307ac04bb6..bc19209e743 100755
--- a/src/compiler/isaspec/encode.py
+++ b/src/compiler/isaspec/encode.py
@@ -69,6 +69,11 @@ class FieldCase(object):
         if case.expr is not None:
             self.expr = isa.expressions[case.expr]
 
+    def signed(self):
+        if self.field.type in ['int', 'offset', 'branch']:
+            return 'true'
+        return 'false'
+
 class AssertField(object):
     def __init__(self, field, case):
         self.field = field
@@ -76,6 +81,9 @@ class AssertField(object):
         if case.expr is not None:
             self.expr = isa.expressions[case.expr]
 
+    def signed(self):
+        return 'false'
+
 # Represents a field to be encoded:
 class DisplayField(object):
     def __init__(self, bitset, case, name):
@@ -369,10 +377,21 @@ struct encode_state;
 struct bitset_params;
 
 static bitmask_t
-pack_field(unsigned low, unsigned high, uint64_t val)
+pack_field(unsigned low, unsigned high, int64_t val, bool is_signed)
 {
    bitmask_t field, mask;
 
+   if (is_signed) {
+      /* NOTE: Don't assume val is already sign-extended to 64b,
+       * just check that the bits above the valid range are either
+       * all zero or all one:
+       */
+      assert(!(( val & ~BITFIELD64_MASK(1 + high - low)) &&
+               (~val & ~BITFIELD64_MASK(1 + high - low))));
+   } else {
+      assert(!(val & ~BITFIELD64_MASK(1 + high - low)));
+   }
+
    BITSET_ZERO(field.bitset);
 
    if (!val)
@@ -593,7 +612,7 @@ isa = s.isa
 %         else:
              fld = ${s.extractor(leaf, f.field.name)};
 %         endif
-             const bitmask_t packed = pack_field(${f.field.low}, ${f.field.high}, fld);  /* ${f.field.name} */
+             const bitmask_t packed = pack_field(${f.field.low}, ${f.field.high}, fld, ${f.signed()});  /* ${f.field.name} */
              BITSET_OR(val.bitset, val.bitset, packed.bitset);
              ${case_post(root, expr)}
 %       endfor
@@ -613,7 +632,7 @@ isa = s.isa
           continue
 %>
        ${case_pre(root, expr)}
-       const bitmask_t packed = pack_field(${f.field.low}, ${f.field.high}, ${f.field.val});
+       const bitmask_t packed = pack_field(${f.field.low}, ${f.field.high}, ${f.field.val}, ${f.signed()});
        BITSET_OR(val.bitset, val.bitset, packed.bitset);
        ${case_post(root, None)}
 %   endfor