Struct FrameTableBuilder 

pub struct FrameTableBuilder { /* private fields */ }

Builder for the Frame Table.

Format:

• num_slot_descriptors: u32
• num_progpoints: u32
• num_breakpoints: u32
• frame_descriptor_pool_length: u32
• progpoint_descriptor_pool_length: u32
• breakpoint_patch_pool_length: u32
• num_slot_descriptors times:
  • frame descriptor offset: u32
  • length: u32
• num_slot_descriptors times:
  • offset from frame up to FP: u32
• num_progpoints times:
  • PC, from start of text section, position (post/pre): u32
    • encoded as (pc << 1) | post_pre_bit
• num_progpoints times:
  • progpoint descriptor offset: u32
• num_breakpoints times:
  • Wasm PC: u32 (sorted order; may repeat)
• num_breakpoints times:
  • patch offset in text: u32
• num_breakpoints times:
  • end of breakpoint patch data in pool: u32 (find the start by end of previous; patches are in the pool in order and this saves storing redundant start/end values)
• frame descriptors (format described above; frame_descriptor_pool_length bytes)
• progpoint descriptors (progpoint_descriptor_pool_length bytes)
  • each descriptor: sequence of frames
    • Wasm PC: u32 (high bit set to indicate a parent frame)
    • slot descriptor index: u32
    • stack shape index: u32 (or u32::MAX for none)
• breakpoint patch pool (breakpoint_patch_pool_length bytes)
  • freeform slices of machine-code bytes to patch in

Implementations

impl FrameTableBuilder

pub fn add_frame_descriptor( &mut self, slot_to_fp_offset: u32, data: &[u8], ) -> FrameTableDescriptorIndex

Add one frame descriptor.

Returns the frame descriptor index.

pub fn add_program_point( &mut self, native_pc: u32, pos: FrameInstPos, frames: &[(u32, FrameTableDescriptorIndex, FrameStackShape)], )

Add one program point.

pub fn add_breakpoint_patch( &mut self, wasm_pc: u32, patch_start_native_pc: u32, patch: &[u8], )

Add one breakpoint patch.

pub fn serialize<F: FnMut(&[u8])>(&mut self, f: F)

Serialize the framd-table data section, taking a closure to consume slices.

Trait Implementations

impl Default for FrameTableBuilder

fn default() -> FrameTableBuilder

Returns the “default value” for a type.