Dev/memory

src/core/error.rs

@@ -6,7 +6,7 @@ use core::str::Utf8Error;
 use crate::core::reader::section_header::SectionTy;
 use crate::core::reader::types::ValType;
 
-use super::indices::MemIdx;
+use super::indices::{DataIdx, MemIdx};
 
 #[derive(Debug, PartialEq, Eq, Clone)]
 pub enum RuntimeError {
@@ -54,6 +54,8 @@ pub enum Error {
     MemoryIsNotDefined(MemIdx),
     //           mem.align, wanted alignment
     ErroneousAlignment(u32, u32),
+    NoDataSegments,
+    DataSegmentNotFound(DataIdx),
 }
 
 impl Display for Error {
@@ -140,6 +142,10 @@ impl Display for Error {
                     mem_align, minimum_wanted_alignment
                 ))
             }
+            Error::NoDataSegments => f.write_str("Data Count is None"),
+            Error::DataSegmentNotFound(data_idx) => {
+                f.write_fmt(format_args!("Data Segment {} not found", data_idx))
+            }
         }
     }
 }

src/core/indices.rs

@@ -22,7 +22,6 @@ pub type MemIdx = usize;
 pub type GlobalIdx = usize;
 #[allow(dead_code)]
 pub type ElemIdx = usize;
-#[allow(dead_code)]
 pub type DataIdx = usize;
 pub type LocalIdx = usize;
 #[allow(dead_code)]

src/core/reader/types/data.rs

@@ -0,0 +1,199 @@
+use core::fmt::{Debug, Formatter};
+
+use alloc::{format, vec::Vec};
+
+use crate::{
+    core::{indices::MemIdx, reader::{span::Span, WasmReadable}},
+    read_constant_expression::read_constant_instructions,
+};
+
+use super::UnwrapValidatedExt;
+
+pub struct DataSegment {
+    pub init: Vec<u8>,
+    pub mode: DataMode,
+}
+
+#[derive(Clone)]
+pub enum DataMode {
+    Passive,
+    Active(DataModeActive),
+}
+
+#[derive(Clone)]
+pub struct DataModeActive {
+    pub memory_idx: MemIdx,
+    pub offset: Span,
+}
+
+impl WasmReadable for DataSegment {
+    fn read(wasm: &mut crate::core::reader::WasmReader) -> crate::Result<Self> {
+        let mode = wasm.read_var_u32()?;
+        let data_sec: DataSegment = match mode {
+            0 => {
+                // active { memory 0, offset e }
+                trace!("Data section: active");
+                let offset = { read_constant_instructions(wasm, None, None)? };
+
+                let byte_vec = wasm.read_vec(|el| el.read_u8())?;
+
+                // WARN: we currently don't take into consideration how we act when we are dealing with globals here
+                DataSegment {
+                    mode: DataMode::Active(DataModeActive {
+                        memory_idx: 0,
+                        offset,
+                    }),
+                    init: byte_vec,
+                }
+            }
+            1 => {
+                // passive
+                // A passive data segment's contents can be copied into a memory using the `memory.init` instruction
+                trace!("Data section: passive");
+                DataSegment {
+                    mode: DataMode::Passive,
+                    init: wasm.read_vec(|el| el.read_u8())?,
+                }
+            }
+            2 => {
+                // mode active { memory x, offset e }
+                // this hasn't been yet implemented in wasm
+                // as per docs:
+
+                // https://webassembly.github.io/spec/core/binary/modules.html#data-section
+                // The initial integer can be interpreted as a bitfield. Bit 0 indicates a passive segment, bit 1 indicates the presence of an explicit memory index for an active segment.
+                // In the current version of WebAssembly, at most one memory may be defined or imported in a single module, so all valid active data segments have a memory value of 0
+                todo!("Data section: active - with multiple memories - NOT YET IMPLEMENTED!");
+            }
+            _ => unreachable!(),
+        };
+
+        trace!("{:?}", data_sec.init);
+        Ok(data_sec)
+    }
+
+    fn read_unvalidated(wasm: &mut crate::core::reader::WasmReader) -> Self {
+        let mode = wasm.read_var_u32().unwrap_validated();
+        let data_sec: DataSegment = match mode {
+            0 => {
+                // active { memory 0, offset e }
+                trace!("Data section: active");
+                let offset = { read_constant_instructions(wasm, None, None).unwrap_validated() };
+
+                let byte_vec = wasm
+                    .read_vec(|el| Ok(el.read_u8().unwrap_validated()))
+                    .unwrap_validated();
+
+                // WARN: we currently don't take into consideration how we act when we are dealing with globals here
+                DataSegment {
+                    mode: DataMode::Active(DataModeActive {
+                        memory_idx: 0,
+                        offset,
+                    }),
+                    init: byte_vec,
+                }
+            }
+            1 => {
+                // passive
+                // A passive data segment's contents can be copied into a memory using the `memory.init` instruction
+                trace!("Data section: passive");
+                DataSegment {
+                    mode: DataMode::Passive,
+                    init: wasm
+                        .read_vec(|el| Ok(el.read_u8().unwrap_validated()))
+                        .unwrap_validated(),
+                }
+            }
+            2 => {
+                // mode active { memory x, offset e }
+                // this hasn't been yet implemented in wasm
+                // as per docs:
+
+                // https://webassembly.github.io/spec/core/binary/modules.html#data-section
+                // The initial integer can be interpreted as a bitfield. Bit 0 indicates a passive segment, bit 1 indicates the presence of an explicit memory index for an active segment.
+                // In the current version of WebAssembly, at most one memory may be defined or imported in a single module, so all valid active data segments have a memory value of 0
+                todo!("Data section: active - with multiple memories - NOT YET IMPLEMENTED!");
+            }
+            _ => unreachable!(),
+        };
+
+        data_sec
+    }
+}
+
+impl Debug for DataSegment {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        let mut init_str = alloc::string::String::new();
+
+        let iter = self.init.iter().peekable();
+        // only if it's valid do we print is as a normal utf-8 char, otherwise, hex
+        for &byte in iter {
+            if let Ok(valid_char) = alloc::string::String::from_utf8(Vec::from(&[byte])) {
+                init_str.push_str(valid_char.as_str());
+            } else {
+                init_str.push_str(&format!("\\x{:02x}", byte));
+            }
+        }
+
+        f.debug_struct("DataSegment")
+            .field("init", &init_str)
+            .field("mode", &self.mode)
+            .finish()
+    }
+}
+
+///
+///  Usually, we'd have something like this:
+/// ```wasm
+/// (module
+///  (memory 1) ;; memory starting with 1 page
+///  (data (i32.const 0) "abc")  ;; writing the array of byte "abc" in the first memory (0) at offset 0
+///                             ;; for hardcoded offsets, we'll usually use i32.const because of wasm being x86 arch
+/// )
+/// ```
+
+///
+/// Since the span has only the start and length and acts a reference, we print the start and end (both inclusive, notice the '..=')
+/// We print it in both decimal and hexadecimal so it's easy to trace in something like <https://webassembly.github.io/wabt/demo/wat2wasm/>
+impl Debug for DataMode {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        match self {
+            DataMode::Passive => f.debug_struct("Passive").finish(),
+            DataMode::Active(active_data_mode) => {
+                let from = active_data_mode.offset.from;
+                let to = active_data_mode.offset.from + active_data_mode.offset.len() - 1;
+                f.debug_struct("Active")
+                    // .field("offset", format_args!("[{}..={}]", from, to))
+                    .field(
+                        "offset",
+                        &format_args!("[{}..={}] (hex = [{:X}..={:X}])", from, to, from, to),
+                    )
+                    .finish()
+                // f.
+            }
+        }
+    }
+}
+
+pub struct PassiveData {
+    pub init: Vec<u8>,
+}
+
+impl Debug for PassiveData {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        let mut init_str = alloc::string::String::new();
+
+        let iter = self.init.iter().peekable();
+        for &byte in iter {
+            if let Ok(valid_char) = alloc::string::String::from_utf8(Vec::from(&[byte])) {
+                init_str.push_str(valid_char.as_str());
+            } else {
+                // If it's not valid UTF-8, print it as hex
+                init_str.push_str(&format!("\\x{:02x}", byte));
+            }
+        }
+        f.debug_struct("PassiveData")
+            .field("init", &init_str)
+            .finish()
+    }
+}

src/core/reader/types/mod.rs

@@ -10,6 +10,7 @@ use crate::execution::assert_validated::UnwrapValidatedExt;
 use crate::Result;
 use crate::{unreachable_validated, Error};
 
+pub mod data;
 pub mod export;
 pub mod function_code_header;
 pub mod global;

src/core/reader/types/opcode.rs

@@ -174,4 +174,8 @@ pub mod fc_extensions {
     pub const I64_TRUNC_SAT_F32_U: u8 = 0x05;
     pub const I64_TRUNC_SAT_F64_S: u8 = 0x06;
     pub const I64_TRUNC_SAT_F64_U: u8 = 0x07;
+    pub const MEMORY_INIT: u8 = 0x08;
+    pub const DATA_DROP: u8 = 0x09;
+    pub const MEMORY_COPY: u8 = 0x0A;
+    pub const MEMORY_FILL: u8 = 0x0B;
 }