all: refactor reflect package

This is a big commit that changes the way runtime type information is stored in
the binary. Instead of compressing it and storing it in a number of sidetables,
it is stored similar to how the Go compiler toolchain stores it (but still more
compactly).

This has a number of advantages:

  * It is much easier to add new features to reflect support. They can simply
    be added to these structs without requiring massive changes (especially in
    the reflect lowering pass).
  * It removes the reflect lowering pass, which was a large amount of hard to
    understand and debug code.
  * The reflect lowering pass also required merging all LLVM IR into one
    module, which is terrible for performance especially when compiling large
    amounts of code. See issue 2870 for details.
  * It is (probably!) easier to reason about for the compiler.

The downside is that it increases code size a bit, especially when reflect is
involved. I hope to fix some of that in later patches.

compiler/testdata/interface.ll

@@ -3,22 +3,17 @@ source_filename = "interface.go"
 target datalayout = "e-m:e-p:32:32-p10:8:8-p20:8:8-i64:64-n32:64-S128-ni:1:10:20"
 target triple = "wasm32-unknown-wasi"
 
-%runtime.typecodeID = type { ptr, i32, ptr, ptr, i32 }
-%runtime._interface = type { i32, ptr }
+%runtime._interface = type { ptr, ptr }
 %runtime._string = type { ptr, i32 }
 
-@"reflect/types.type:basic:int" = linkonce_odr constant %runtime.typecodeID { ptr null, i32 0, ptr null, ptr @"reflect/types.type:pointer:basic:int", i32 0 }
-@"reflect/types.type:pointer:basic:int" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:basic:int", i32 0, ptr null, ptr null, i32 0 }
-@"reflect/types.type:pointer:named:error" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:named:error", i32 0, ptr null, ptr null, i32 0 }
-@"reflect/types.type:named:error" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", i32 0, ptr null, ptr @"reflect/types.type:pointer:named:error", i32 ptrtoint (ptr @"interface:{Error:func:{}{basic:string}}.$typeassert" to i32) }
-@"reflect/types.type:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.interface:interface{Error() string}$interface", i32 0, ptr null, ptr @"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}", i32 ptrtoint (ptr @"interface:{Error:func:{}{basic:string}}.$typeassert" to i32) }
-@"reflect/methods.Error() string" = linkonce_odr constant i8 0, align 1
-@"reflect/types.interface:interface{Error() string}$interface" = linkonce_odr constant [1 x ptr] [ptr @"reflect/methods.Error() string"]
-@"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}", i32 0, ptr null, ptr null, i32 0 }
-@"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.type:interface:{String:func:{}{basic:string}}", i32 0, ptr null, ptr null, i32 0 }
-@"reflect/types.type:interface:{String:func:{}{basic:string}}" = linkonce_odr constant %runtime.typecodeID { ptr @"reflect/types.interface:interface{String() string}$interface", i32 0, ptr null, ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}", i32 ptrtoint (ptr @"interface:{String:func:{}{basic:string}}.$typeassert" to i32) }
-@"reflect/methods.String() string" = linkonce_odr constant i8 0, align 1
-@"reflect/types.interface:interface{String() string}$interface" = linkonce_odr constant [1 x ptr] [ptr @"reflect/methods.String() string"]
+@"reflect/types.type:basic:int" = linkonce_odr constant { i8, ptr } { i8 2, ptr @"reflect/types.type:pointer:basic:int" }, align 4
+@"reflect/types.type:pointer:basic:int" = linkonce_odr constant { i8, ptr } { i8 21, ptr @"reflect/types.type:basic:int" }, align 4
+@"reflect/types.type:pointer:named:error" = linkonce_odr constant { i8, ptr } { i8 21, ptr @"reflect/types.type:named:error" }, align 4
+@"reflect/types.type:named:error" = linkonce_odr constant { i8, ptr, ptr } { i8 52, ptr @"reflect/types.type:pointer:named:error", ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}" }, align 4
+@"reflect/types.type:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant { i8, ptr } { i8 20, ptr @"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" }, align 4
+@"reflect/types.type:pointer:interface:{Error:func:{}{basic:string}}" = linkonce_odr constant { i8, ptr } { i8 21, ptr @"reflect/types.type:interface:{Error:func:{}{basic:string}}" }, align 4
+@"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" = linkonce_odr constant { i8, ptr } { i8 21, ptr @"reflect/types.type:interface:{String:func:{}{basic:string}}" }, align 4
+@"reflect/types.type:interface:{String:func:{}{basic:string}}" = linkonce_odr constant { i8, ptr } { i8 20, ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" }, align 4
 @"reflect/types.typeid:basic:int" = external constant i8
 
 declare noalias nonnull ptr @runtime.alloc(i32, ptr, ptr) #0
@@ -35,42 +30,42 @@ entry:
 define hidden %runtime._interface @main.simpleType(ptr %context) unnamed_addr #1 {
 entry:
   %stackalloc = alloca i8, align 1
+  call void @runtime.trackPointer(ptr nonnull @"reflect/types.type:basic:int", ptr nonnull %stackalloc, ptr undef) #6
   call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
-  ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:basic:int" to i32), ptr null }
+  ret %runtime._interface { ptr @"reflect/types.type:basic:int", ptr null }
 }
 
 ; Function Attrs: nounwind
 define hidden %runtime._interface @main.pointerType(ptr %context) unnamed_addr #1 {
 entry:
   %stackalloc = alloca i8, align 1
+  call void @runtime.trackPointer(ptr nonnull @"reflect/types.type:pointer:basic:int", ptr nonnull %stackalloc, ptr undef) #6
   call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
-  ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:basic:int" to i32), ptr null }
+  ret %runtime._interface { ptr @"reflect/types.type:pointer:basic:int", ptr null }
 }
 
 ; Function Attrs: nounwind
 define hidden %runtime._interface @main.interfaceType(ptr %context) unnamed_addr #1 {
 entry:
   %stackalloc = alloca i8, align 1
+  call void @runtime.trackPointer(ptr nonnull @"reflect/types.type:pointer:named:error", ptr nonnull %stackalloc, ptr undef) #6
   call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
-  ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:named:error" to i32), ptr null }
+  ret %runtime._interface { ptr @"reflect/types.type:pointer:named:error", ptr null }
 }
 
-declare i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(i32) #2
-
 ; Function Attrs: nounwind
 define hidden %runtime._interface @main.anonymousInterfaceType(ptr %context) unnamed_addr #1 {
 entry:
   %stackalloc = alloca i8, align 1
+  call void @runtime.trackPointer(ptr nonnull @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}", ptr nonnull %stackalloc, ptr undef) #6
   call void @runtime.trackPointer(ptr null, ptr nonnull %stackalloc, ptr undef) #6
-  ret %runtime._interface { i32 ptrtoint (ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}" to i32), ptr null }
+  ret %runtime._interface { ptr @"reflect/types.type:pointer:interface:{String:func:{}{basic:string}}", ptr null }
 }
 
-declare i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(i32) #3
-
 ; Function Attrs: nounwind
-define hidden i1 @main.isInt(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
+define hidden i1 @main.isInt(ptr %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
 entry:
-  %typecode = call i1 @runtime.typeAssert(i32 %itf.typecode, ptr nonnull @"reflect/types.typeid:basic:int", ptr undef) #6
+  %typecode = call i1 @runtime.typeAssert(ptr %itf.typecode, ptr nonnull @"reflect/types.typeid:basic:int", ptr undef) #6
   br i1 %typecode, label %typeassert.ok, label %typeassert.next
 
 typeassert.next:                                  ; preds = %typeassert.ok, %entry
@@ -80,12 +75,12 @@ typeassert.ok:                                    ; preds = %entry
   br label %typeassert.next
 }
 
-declare i1 @runtime.typeAssert(i32, ptr dereferenceable_or_null(1), ptr) #0
+declare i1 @runtime.typeAssert(ptr, ptr dereferenceable_or_null(1), ptr) #0
 
 ; Function Attrs: nounwind
-define hidden i1 @main.isError(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
+define hidden i1 @main.isError(ptr %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
 entry:
-  %0 = call i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(i32 %itf.typecode) #6
+  %0 = call i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(ptr %itf.typecode) #6
   br i1 %0, label %typeassert.ok, label %typeassert.next
 
 typeassert.next:                                  ; preds = %typeassert.ok, %entry
@@ -95,10 +90,12 @@ typeassert.ok:                                    ; preds = %entry
   br label %typeassert.next
 }
 
+declare i1 @"interface:{Error:func:{}{basic:string}}.$typeassert"(ptr) #2
+
 ; Function Attrs: nounwind
-define hidden i1 @main.isStringer(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
+define hidden i1 @main.isStringer(ptr %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
 entry:
-  %0 = call i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(i32 %itf.typecode) #6
+  %0 = call i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(ptr %itf.typecode) #6
   br i1 %0, label %typeassert.ok, label %typeassert.next
 
 typeassert.next:                                  ; preds = %typeassert.ok, %entry
@@ -108,26 +105,28 @@ typeassert.ok:                                    ; preds = %entry
   br label %typeassert.next
 }
 
+declare i1 @"interface:{String:func:{}{basic:string}}.$typeassert"(ptr) #3
+
 ; Function Attrs: nounwind
-define hidden i8 @main.callFooMethod(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
+define hidden i8 @main.callFooMethod(ptr %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
 entry:
-  %0 = call i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr %itf.value, i32 3, i32 %itf.typecode, ptr undef) #6
+  %0 = call i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr %itf.value, i32 3, ptr %itf.typecode, ptr undef) #6
   ret i8 %0
 }
 
-declare i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr, i32, i32, ptr) #4
+declare i8 @"interface:{String:func:{}{basic:string},main.foo:func:{basic:int}{basic:uint8}}.foo$invoke"(ptr, i32, ptr, ptr) #4
 
 ; Function Attrs: nounwind
-define hidden %runtime._string @main.callErrorMethod(i32 %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
+define hidden %runtime._string @main.callErrorMethod(ptr %itf.typecode, ptr %itf.value, ptr %context) unnamed_addr #1 {
 entry:
   %stackalloc = alloca i8, align 1
-  %0 = call %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr %itf.value, i32 %itf.typecode, ptr undef) #6
+  %0 = call %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr %itf.value, ptr %itf.typecode, ptr undef) #6
   %1 = extractvalue %runtime._string %0, 0
   call void @runtime.trackPointer(ptr %1, ptr nonnull %stackalloc, ptr undef) #6
   ret %runtime._string %0
 }
 
-declare %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr, i32, ptr) #5
+declare %runtime._string @"interface:{Error:func:{}{basic:string}}.Error$invoke"(ptr, ptr, ptr) #5
 
 attributes #0 = { "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }
 attributes #1 = { nounwind "target-features"="+bulk-memory,+nontrapping-fptoint,+sign-ext" }