[lisa] Make go_marshal pass correctly sized buffers to safecopy.

gohacks.Memmove() takes in the number of bytes to move. The current generated
code passes len(src) and len(dst) as the number of bytes to move.

However, the marshal.Marshallable interface allows passing in larger buffers.
The stated precondition is that the buffer should be "at least" SizeBytes()
in length but it is allowed to be larger.

This change now correctly calls Memmove with the argument for the number of
bytes to move as type.SizeBytes(). This was caught when I made lisafs use the
Unsafe marshalling API and got a lot of memory violations.

PiperOrigin-RevId: 368952642

3 files changed, 8 insertions, 8 deletions

diff --git a/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go b/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
index e8ce6e366..bd7741ae5 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_array_newtype.go
@@ -89,14 +89,14 @@ func (g *interfaceGenerator) emitMarshallableForArrayNewtype(n *ast.Ident, a *as
 	g.emit("// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.\n")
 	g.emit("func (%s *%s) MarshalUnsafe(dst []byte) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(&%s[0]), uintptr(len(dst)))\n", g.r)
+		g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(&%s[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
 	g.emit("// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.\n")
 	g.emit("func (%s *%s) UnmarshalUnsafe(src []byte) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
+		g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
diff --git a/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go b/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
index 19aa5994a..ba4b7324e 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_primitive_newtype.go
@@ -141,14 +141,14 @@ func (g *interfaceGenerator) emitMarshallableForPrimitiveNewtype(nt *ast.Ident)
 	g.emit("// MarshalUnsafe implements marshal.Marshallable.MarshalUnsafe.\n")
 	g.emit("func (%s *%s) MarshalUnsafe(dst []byte) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(len(dst)))\n", g.r)
+		g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
 	g.emit("// UnmarshalUnsafe implements marshal.Marshallable.UnmarshalUnsafe.\n")
 	g.emit("func (%s *%s) UnmarshalUnsafe(src []byte) {\n", g.r, g.typeName())
 	g.inIndent(func() {
-		g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
+		g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 	})
 	g.emit("}\n\n")
 
diff --git a/tools/go_marshal/gomarshal/generator_interfaces_struct.go b/tools/go_marshal/gomarshal/generator_interfaces_struct.go
index 087c88b54..4c47218f1 100644
--- a/tools/go_marshal/gomarshal/generator_interfaces_struct.go
+++ b/tools/go_marshal/gomarshal/generator_interfaces_struct.go
@@ -275,13 +275,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 			if cond, ok := g.areFieldsPackedExpression(); ok {
 				g.emit("if %s {\n", cond)
 				g.inIndent(func() {
-					g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s),  uintptr(len(dst)))\n", g.r)
+					g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s),  uintptr(%s.SizeBytes()))\n", g.r, g.r)
 				})
 				g.emit("} else {\n")
 				g.inIndent(fallback)
 				g.emit("}\n")
 			} else {
-				g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s),  uintptr(len(dst)))\n", g.r)
+				g.emit("gohacks.Memmove(unsafe.Pointer(&dst[0]), unsafe.Pointer(%s),  uintptr(%s.SizeBytes()))\n", g.r, g.r)
 			}
 		} else {
 			fallback()
@@ -301,13 +301,13 @@ func (g *interfaceGenerator) emitMarshallableForStruct(st *ast.StructType) {
 			if cond, ok := g.areFieldsPackedExpression(); ok {
 				g.emit("if %s {\n", cond)
 				g.inIndent(func() {
-					g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
+					g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 				})
 				g.emit("} else {\n")
 				g.inIndent(fallback)
 				g.emit("}\n")
 			} else {
-				g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(len(src)))\n", g.r)
+				g.emit("gohacks.Memmove(unsafe.Pointer(%s), unsafe.Pointer(&src[0]), uintptr(%s.SizeBytes()))\n", g.r, g.r)
 			}
 		} else {
 			fallback()