feat: constrain sha256

barretenberg/cpp/.clangd

@@ -80,3 +80,12 @@ Diagnostics:
     Remove:
       - cppcoreguidelines-avoid-non-const-global-variables
       - cppcoreguidelines-special-member-functions
+
+--- # this divider is necessary
+# Suppressing some noisy AVM warnings
+If:
+  PathMatch: [src/barretenberg/vm.*\.cpp]
+Diagnostics:
+  Suppress:
+    - -Wmissing-designated-field-initializers
+

barretenberg/cpp/pil/vm2/execution.pil

@@ -1,6 +1,7 @@
 include "alu.pil";
 include "addressing.pil";
 include "precomputed.pil";
+include "sha256.pil";
 
 namespace execution;
 
@@ -53,4 +54,4 @@ precomputed.sel_bitwise {precomputed.bitwise_op_id, precomputed.bitwise_input_a,
 #[LOOKUP_DUMMY_DYNAMIC]  // Just a self-lookup for now, for testing.
 sel {op1, op2, op3, op4} in sel {op1, op2, op3, op4};
 #[PERM_DUMMY_DYNAMIC]  // Just a self-permutation for now, for testing.
-sel {op1, op2, op3, op4} is sel {op1, op2, op3, op4};
+sel {op1, op2, op3, op4} is sel {op1, op2, op3, op4};

barretenberg/cpp/pil/vm2/precomputed.pil

@@ -14,4 +14,8 @@ pol constant sel_bitwise; // 1 in the first 3 * 256 rows.
 pol constant bitwise_op_id; // identifies if operation is AND/OR/XOR.
 pol constant bitwise_input_a; // column of all 8-bit numbers.
 pol constant bitwise_input_b; // column of all 8-bit numbers.
-pol constant bitwise_output; // output = a AND/OR/XOR b.
+pol constant bitwise_output; // output = a AND/OR/XOR b.
+
+// SHA256 Round Params Lookup
+pol constant sel_sha256_compression;
+pol constant sha256_compression_round_constant;