cmd/link: put itabs in the .go.type section

For #76038

Change-Id: I4c30d5854fcaacc7fd7f84b4679a5be30379122d
Reviewed-on: https://go-review.googlesource.com/c/go/+/729200
Reviewed-by: Cherry Mui <cherryyz@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Mark Freeman <markfreeman@google.com>
Reviewed-by: Pagol Mon <mpagol707@gmail.com>

2 files changed, 31 insertions, 28 deletions

diff --git a/src/cmd/link/internal/ld/data.go b/src/cmd/link/internal/ld/data.go
index 89df83cfeb..1265b028e6 100644
--- a/src/cmd/link/internal/ld/data.go
+++ b/src/cmd/link/internal/ld/data.go
@@ -2430,6 +2430,7 @@ func (state *dodataState) dodataSect(ctxt *Link, symn sym.SymKind, syms []loader
 		// Sort type descriptors with the typelink flag first,
 		// sorted by type string. The reflect package will use
 		// this to ensure that type descriptor pointers are unique.
+		// Sort itabs after type descriptors.
 
 		// We define type:* for some links.
 		typeStar := ldr.Lookup("type:*", 0)
@@ -2458,23 +2459,32 @@ func (state *dodataState) dodataSect(ctxt *Link, symn sym.SymKind, syms []loader
 				}
 			}
 
-			iTypestr, iIsTypelink := typelinkStrings[si]
-			jTypestr, jIsTypelink := typelinkStrings[sj]
+			iIsType := !ldr.IsItab(si)
+			jIsType := !ldr.IsItab(sj)
+			if iIsType && jIsType {
+				iTypestr, iIsTypelink := typelinkStrings[si]
+				jTypestr, jIsTypelink := typelinkStrings[sj]
 
-			if iIsTypelink {
-				if jIsTypelink {
+				if iIsTypelink && jIsTypelink {
 					// typelink symbols sort by type string
 					return iTypestr < jTypestr
+				} else if iIsTypelink {
+					// typelink < non-typelink
+					return true
+				} else if jIsTypelink {
+					// non-typelink > typelink
+					return false
 				}
-
-				// typelink < non-typelink
+			} else if iIsType {
+				// type < itab
 				return true
-			} else if jIsTypelink {
-				// non-typelink greater than typelink
+			} else if jIsType {
+				// itab > type
 				return false
 			}
 
-			// non-typelink symbols sort by size as usual
+			// Otherwise, within non-typelink types and itabs,
+			// sort by size as usual.
 			return sortFn(i, j)
 		})
 
diff --git a/src/cmd/link/internal/ld/symtab.go b/src/cmd/link/internal/ld/symtab.go
index b88cfd3386..3dc2adc810 100644
--- a/src/cmd/link/internal/ld/symtab.go
+++ b/src/cmd/link/internal/ld/symtab.go
@@ -459,15 +459,12 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
 	ctxt.xdefine("runtime.egcbss", sym.SRODATA, 0)
 
 	// pseudo-symbols to mark locations of type, string, and go string data.
-	var symtype loader.Sym
-	if !ctxt.DynlinkingGo() {
-		s = ldr.CreateSymForUpdate("type:*", 0)
-		s.SetType(sym.STYPE)
-		s.SetSize(0)
-		s.SetAlign(int32(ctxt.Arch.PtrSize))
-		symtype = s.Sym()
-		setCarrierSym(sym.STYPE, symtype)
-	}
+	s = ldr.CreateSymForUpdate("type:*", 0)
+	s.SetType(sym.STYPE)
+	s.SetSize(0)
+	s.SetAlign(int32(ctxt.Arch.PtrSize))
+	symtype := s.Sym()
+	setCarrierSym(sym.STYPE, symtype)
 
 	groupSym := func(name string, t sym.SymKind) loader.Sym {
 		s := ldr.CreateSymForUpdate(name, 0)
@@ -523,20 +520,16 @@ func (ctxt *Link) symtab(pcln *pclntab) []sym.SymKind {
 		case strings.HasPrefix(name, "type:"):
 			if !ctxt.DynlinkingGo() {
 				ldr.SetAttrNotInSymbolTable(s, true)
+				ldr.SetCarrierSym(s, symtype)
 			}
 			symGroupType[s] = sym.STYPE
-			if symtype != 0 {
+
+		case ldr.IsItab(s):
+			if !ctxt.DynlinkingGo() {
+				ldr.SetAttrNotInSymbolTable(s, true)
 				ldr.SetCarrierSym(s, symtype)
 			}
-			if ctxt.HeadType == objabi.Haix {
-				// The default alignment is currently 0x20,
-				// which the AIX external linker doesn't
-				// seem to support. To get consistent
-				// alignment on AIX, force alignment to 8.
-				if symalign(ldr, s) > 8 {
-					ldr.SetSymAlign(s, 8)
-				}
-			}
+			symGroupType[s] = sym.STYPE
 		}
 	}