InternPool: pass by const pointer

The Zig language allows the compiler to make this optimization
automatically. We should definitely make the compiler do that, and
revert this commit. However, that will not happen in this branch, and I
want to continue to explore achieving performance parity with
merge-base. So, this commit changes all InternPool parameters to be
passed by const pointer rather than by value.

I measured a 1.03x ± 0.03 speedup vs the previous commit compiling the
(set of passing) behavior tests. Against merge-base, this commit is
1.17x ± 0.04 slower, which is an improvement from the previous
measurement of 1.22x ± 0.02.

Related issue: #13510
Related issue: #14129
Related issue: #15688

1 files changed, 3 insertions, 3 deletions

diff --git a/src/arch/wasm/CodeGen.zig b/src/arch/wasm/CodeGen.zig
index af2b37312d..e397cf29f8 100644
--- a/src/arch/wasm/CodeGen.zig
+++ b/src/arch/wasm/CodeGen.zig
@@ -2076,7 +2076,7 @@ fn genBody(func: *CodeGen, body: []const Air.Inst.Index) InnerError!void {
     const ip = &mod.intern_pool;
 
     for (body) |inst| {
-        if (func.liveness.isUnused(inst) and !func.air.mustLower(inst, ip.*)) {
+        if (func.liveness.isUnused(inst) and !func.air.mustLower(inst, ip)) {
             continue;
         }
         const old_bookkeeping_value = func.air_bookkeeping;
@@ -7436,10 +7436,10 @@ fn airFrameAddress(func: *CodeGen, inst: Air.Inst.Index) InnerError!void {
 
 fn typeOf(func: *CodeGen, inst: Air.Inst.Ref) Type {
     const mod = func.bin_file.base.options.module.?;
-    return func.air.typeOf(inst, mod.intern_pool);
+    return func.air.typeOf(inst, &mod.intern_pool);
 }
 
 fn typeOfIndex(func: *CodeGen, inst: Air.Inst.Index) Type {
     const mod = func.bin_file.base.options.module.?;
-    return func.air.typeOfIndex(inst, mod.intern_pool);
+    return func.air.typeOfIndex(inst, &mod.intern_pool);
 }