Remove memory-related cases from RelocationTarget (#949)

This commit shrinks the `RelocationTarget` enumeration to remove
intrinsic-related relocations since they are no longer used. Instead
these function calls are done indirectly via a table in the `VMContext`.
This means that all of this is essentially dead code!

crates/environ/src/compilation.rs

@@ -247,14 +247,6 @@ pub enum RelocationTarget {
     UserFunc(FuncIndex),
     /// A compiler-generated libcall.
     LibCall(ir::LibCall),
-    /// Function for growing a locally-defined 32-bit memory by the specified amount of pages.
-    Memory32Grow,
-    /// Function for growing an imported 32-bit memory by the specified amount of pages.
-    ImportedMemory32Grow,
-    /// Function for query current size of a locally-defined 32-bit linear memory.
-    Memory32Size,
-    /// Function for query current size of an imported 32-bit linear memory.
-    ImportedMemory32Size,
     /// Jump table index.
     JumpTable(FuncIndex, ir::JumpTable),
 }

crates/environ/src/cranelift.rs

@@ -6,10 +6,7 @@ use crate::compilation::{
     Compilation, CompileError, CompiledFunction, CompiledFunctionUnwindInfo, Relocation,
     RelocationTarget, TrapInformation,
 };
-use crate::func_environ::{
+use crate::func_environ::{get_func_name, FuncEnvironment};
-    get_func_name, get_imported_memory32_grow_name, get_imported_memory32_size_name,
-    get_memory32_grow_name, get_memory32_size_name, FuncEnvironment,
-};
 use crate::module::Module;
 use crate::module_environ::FunctionBodyData;
 use crate::CacheConfig;
@@ -46,15 +43,7 @@ impl binemit::RelocSink for RelocSink {
         name: &ExternalName,
         addend: binemit::Addend,
     ) {
-        let reloc_target = if *name == get_memory32_grow_name() {
+        let reloc_target = if let ExternalName::User { namespace, index } = *name {
-            RelocationTarget::Memory32Grow
-        } else if *name == get_imported_memory32_grow_name() {
-            RelocationTarget::ImportedMemory32Grow
-        } else if *name == get_memory32_size_name() {
-            RelocationTarget::Memory32Size
-        } else if *name == get_imported_memory32_size_name() {
-            RelocationTarget::ImportedMemory32Size
-        } else if let ExternalName::User { namespace, index } = *name {
             debug_assert_eq!(namespace, 0);
             RelocationTarget::UserFunc(FuncIndex::from_u32(index))
         } else if let ExternalName::LibCall(libcall) = *name {

crates/environ/src/func_environ.rs

@@ -22,30 +22,6 @@ pub fn get_func_name(func_index: FuncIndex) -> ir::ExternalName {
     ir::ExternalName::user(0, func_index.as_u32())
 }
 
-/// Compute an `ir::ExternalName` for the `memory.grow` libcall for
-/// 32-bit locally-defined memories.
-pub fn get_memory32_grow_name() -> ir::ExternalName {
-    ir::ExternalName::user(1, 0)
-}
-
-/// Compute an `ir::ExternalName` for the `memory.grow` libcall for
-/// 32-bit imported memories.
-pub fn get_imported_memory32_grow_name() -> ir::ExternalName {
-    ir::ExternalName::user(1, 1)
-}
-
-/// Compute an `ir::ExternalName` for the `memory.size` libcall for
-/// 32-bit locally-defined memories.
-pub fn get_memory32_size_name() -> ir::ExternalName {
-    ir::ExternalName::user(1, 2)
-}
-
-/// Compute an `ir::ExternalName` for the `memory.size` libcall for
-/// 32-bit imported memories.
-pub fn get_imported_memory32_size_name() -> ir::ExternalName {
-    ir::ExternalName::user(1, 3)
-}
-
 /// An index type for builtin functions.
 pub struct BuiltinFunctionIndex(u32);
 

crates/jit/src/link.rs

@@ -29,10 +29,6 @@ pub fn link_module(
                     }
                     None => panic!("direct call to import"),
                 },
-                RelocationTarget::Memory32Grow => wasmtime_memory32_grow as usize,
-                RelocationTarget::Memory32Size => wasmtime_memory32_size as usize,
-                RelocationTarget::ImportedMemory32Grow => wasmtime_imported_memory32_grow as usize,
-                RelocationTarget::ImportedMemory32Size => wasmtime_imported_memory32_size as usize,
                 RelocationTarget::LibCall(libcall) => {
                     use cranelift_codegen::ir::LibCall::*;
                     match libcall {

crates/obj/src/function.rs

@@ -5,16 +5,6 @@ use wasmtime_environ::settings;
 use wasmtime_environ::settings::Configurable;
 use wasmtime_environ::{Compilation, Module, RelocationTarget, Relocations};
 
-fn get_reloc_target_special_import_name(target: RelocationTarget) -> Option<&'static str> {
-    Some(match target {
-        RelocationTarget::Memory32Grow => &"wasmtime_memory32_grow",
-        RelocationTarget::ImportedMemory32Grow => &"wasmtime_memory32_grow",
-        RelocationTarget::Memory32Size => &"wasmtime_memory32_size",
-        RelocationTarget::ImportedMemory32Size => &"wasmtime_imported_memory32_size",
-        _ => return None,
-    })
-}
-
 /// Defines module functions
 pub fn declare_functions(
     obj: &mut Artifact,
@@ -25,14 +15,6 @@ pub fn declare_functions(
         let string_name = format!("_wasm_function_{}", i);
         obj.declare(string_name, Decl::function_import())?;
     }
-    for (_, function_relocs) in relocations.iter() {
-        for r in function_relocs {
-            let special_import_name = get_reloc_target_special_import_name(r.reloc_target);
-            if let Some(special_import_name) = special_import_name {
-                obj.declare(special_import_name, Decl::function_import())?;
-            }
-        }
-    }
     for (i, _function_relocs) in relocations.iter().rev() {
         let func_index = module.func_index(i);
         let string_name = format!("_wasm_function_{}", func_index.index());
@@ -81,16 +63,6 @@ pub fn emit_functions(
                         at: r.offset as u64,
                     })?;
                 }
-                RelocationTarget::Memory32Grow
-                | RelocationTarget::ImportedMemory32Grow
-                | RelocationTarget::Memory32Size
-                | RelocationTarget::ImportedMemory32Size => {
-                    obj.link(Link {
-                        from: &string_name,
-                        to: get_reloc_target_special_import_name(r.reloc_target).expect("name"),
-                        at: r.offset as u64,
-                    })?;
-                }
                 RelocationTarget::JumpTable(_, _) => {
                     // ignore relocations for jump tables
                 }