Revert "Feat/HINT_BUFFER opcode for Rv32 (#1256)" (#1277)

This reverts commit 208e00d.

crates/toolchain/openvm/src/io/mod.rs

@@ -6,7 +6,7 @@ use core::alloc::Layout;
 use core::fmt::Write;
 
 #[cfg(target_os = "zkvm")]
-use openvm_rv32im_guest::{hint_buffer_u32, hint_input, hint_store_u32};
+use openvm_rv32im_guest::{hint_input, hint_store_u32};
 use serde::de::DeserializeOwned;
 
 #[cfg(not(target_os = "zkvm"))]
@@ -37,7 +37,7 @@ pub fn read<T: DeserializeOwned>() -> T {
 pub fn read_u32() -> u32 {
     let ptr = unsafe { alloc::alloc::alloc(Layout::from_size_align(4, 4).unwrap()) };
     let addr = ptr as u32;
-    hint_store_u32!(addr);
+    hint_store_u32!(addr, 0);
     let result: u32;
     unsafe {
         core::arch::asm!("lw {rd}, ({rs1})", rd = out(reg) result, rs1 = in(reg) addr);
@@ -47,7 +47,7 @@ pub fn read_u32() -> u32 {
 
 fn hint_store_word(ptr: *mut u32) {
     #[cfg(target_os = "zkvm")]
-    hint_store_u32!(ptr);
+    hint_store_u32!(ptr, 0);
     #[cfg(not(target_os = "zkvm"))]
     unsafe {
         *ptr = crate::host::read_u32();
@@ -68,7 +68,11 @@ pub(crate) fn read_vec_by_len(len: usize) -> Vec<u8> {
         let ptr_start = unsafe { alloc::alloc::alloc(layout) };
         let mut ptr = ptr_start;
 
-        hint_buffer_u32!(ptr, num_words);
+        // Note: if len % 4 != 0, this will discard some last bytes
+        for _ in 0..num_words {
+            hint_store_u32!(ptr, 0);
+            ptr = unsafe { ptr.add(4) };
+        }
         unsafe { Vec::from_raw_parts(ptr_start, len, capacity) }
     }
     #[cfg(not(target_os = "zkvm"))]

crates/toolchain/openvm/src/io/read.rs

@@ -1,8 +1,6 @@
 use core::mem::MaybeUninit;
 
 use openvm_platform::WORD_SIZE;
-#[cfg(target_os = "zkvm")]
-use openvm_rv32im_guest::hint_buffer_u32;
 
 use super::hint_store_word;
 use crate::serde::WordRead;
@@ -30,15 +28,10 @@ impl WordRead for Reader {
     fn read_words(&mut self, words: &mut [u32]) -> crate::serde::Result<()> {
         let num_words = words.len();
         if let Some(new_remaining) = self.bytes_remaining.checked_sub(num_words * WORD_SIZE) {
-            #[cfg(target_os = "zkvm")]
-            hint_buffer_u32!(words.as_mut_ptr(), words.len());
-            #[cfg(not(target_os = "zkvm"))]
-            {
-                for w in words.iter_mut() {
-                    hint_store_word(w as *mut u32);
-                }
-                self.bytes_remaining = new_remaining;
+            for w in words.iter_mut() {
+                hint_store_word(w as *mut u32);
             }
+            self.bytes_remaining = new_remaining;
             Ok(())
         } else {
             Err(crate::serde::Error::DeserializeUnexpectedEnd)
@@ -50,17 +43,11 @@ impl WordRead for Reader {
             return Err(crate::serde::Error::DeserializeUnexpectedEnd);
         }
         let mut num_padded_bytes = bytes.len();
-        #[cfg(target_os = "zkvm")]
-        hint_buffer_u32!(bytes as *mut [u8] as *mut u32, num_padded_bytes / WORD_SIZE);
-        #[cfg(not(target_os = "zkvm"))]
-        {
-            let mut words = bytes.chunks_exact_mut(WORD_SIZE);
-            for word in &mut words {
-                hint_store_word(word as *mut [u8] as *mut u32);
-            }
+        let mut words = bytes.chunks_exact_mut(WORD_SIZE);
+        for word in &mut words {
+            hint_store_word(word as *mut [u8] as *mut u32);
         }
-
-        let remainder = bytes.chunks_exact_mut(WORD_SIZE).into_remainder();
+        let remainder = words.into_remainder();
         if !remainder.is_empty() {
             num_padded_bytes += WORD_SIZE - remainder.len();
             let mut padded = MaybeUninit::<[u8; WORD_SIZE]>::uninit();

extensions/ecc/sw-macros/src/lib.rs

@@ -313,7 +313,10 @@ pub fn sw_declare(input: TokenStream) -> TokenStream {
                                 #hint_decompress_extern_func(x as *const _ as usize, rec_id as *const u8 as usize);
                                 let mut ptr = y.as_ptr() as *const u8;
                                 // NOTE[jpw]: this loop could be unrolled using seq_macro and hint_store_u32(ptr, $imm)
-                                openvm_rv32im_guest::hint_buffer_u32!(ptr, <#intmod_type as openvm_algebra_guest::IntMod>::NUM_LIMBS / 4);
+                                for _ in (0..<#intmod_type as openvm_algebra_guest::IntMod>::NUM_LIMBS).step_by(4) {
+                                    openvm_rv32im_guest::hint_store_u32!(ptr, 0);
+                                    ptr = ptr.add(4);
+                                }
                                 y.assume_init()
                             }
                         }

extensions/pairing/guest/src/bls12_381/pairing.rs

@@ -13,7 +13,6 @@ use {
     core::mem::MaybeUninit,
     openvm_platform::custom_insn_r,
     openvm_rv32im_guest,
-    openvm_rv32im_guest::hint_buffer_u32,
 };
 
 use super::{Bls12_381, Fp, Fp12, Fp2};
@@ -330,8 +329,12 @@ impl PairingCheck for Bls12_381 {
                     rs1 = In &p_fat_ptr,
                     rs2 = In &q_fat_ptr
                 );
-                let ptr = hint.as_ptr() as *const u8;
-                hint_buffer_u32!(ptr, (48 * 12 * 2) / 4);
+                let mut ptr = hint.as_ptr() as *const u8;
+                // NOTE[jpw]: this loop could be unrolled using seq_macro and hint_store_u32(ptr, $imm)
+                for _ in (0..48 * 12 * 2).step_by(4) {
+                    openvm_rv32im_guest::hint_store_u32!(ptr, 0);
+                    ptr = ptr.add(4);
+                }
                 hint.assume_init()
             }
         }

extensions/pairing/guest/src/bn254/pairing.rs

@@ -9,7 +9,6 @@ use {
     crate::{PairingBaseFunct7, OPCODE, PAIRING_FUNCT3},
     core::mem::MaybeUninit,
     openvm_platform::custom_insn_r,
-    openvm_rv32im_guest::hint_buffer_u32,
 };
 
 use super::{Bn254, Fp, Fp12, Fp2};
@@ -362,9 +361,12 @@ impl PairingCheck for Bn254 {
                     rs1 = In &p_fat_ptr,
                     rs2 = In &q_fat_ptr
                 );
-                let ptr = hint.as_ptr() as *const u8;
+                let mut ptr = hint.as_ptr() as *const u8;
                 // NOTE[jpw]: this loop could be unrolled using seq_macro and hint_store_u32(ptr, $imm)
-                hint_buffer_u32!(ptr, (32 * 12 * 2) / 4);
+                for _ in (0..32 * 12 * 2).step_by(4) {
+                    openvm_rv32im_guest::hint_store_u32!(ptr, 0);
+                    ptr = ptr.add(4);
+                }
                 hint.assume_init()
             }
         }

extensions/rv32im/circuit/Cargo.toml

@@ -17,7 +17,6 @@ openvm-circuit-derive = { workspace = true }
 openvm-instructions = { workspace = true }
 openvm-rv32im-transpiler = { workspace = true }
 
-bitcode.workspace = true
 strum.workspace = true
 itertools.workspace = true
 tracing.workspace = true