Add support for new WASM_SEGMENT_FLAG_RETAIN segment flag (#2399)

See llvm/llvm-project#81539

Author: kateinoigakukun

include/wabt/common.h

@@ -333,6 +333,7 @@ enum class ComdatType {
 
 #define WABT_SEGMENT_FLAG_STRINGS 0x1
 #define WABT_SEGMENT_FLAG_TLS 0x2
+#define WASM_SEGMENT_FLAG_RETAIN 0x4
 #define WABT_SEGMENT_FLAG_MAX 0xff
 
 enum class SymbolVisibility {

src/binary-reader-objdump.cc

@@ -2206,6 +2206,10 @@ Result BinaryReaderObjdump::PrintSegmentFlags(uint32_t flags) {
     PrintDetails(" TLS");
     flags &= ~WABT_SEGMENT_FLAG_TLS;
   }
+  if (flags & WASM_SEGMENT_FLAG_RETAIN) {
+    PrintDetails(" RETAIN");
+    flags &= ~WASM_SEGMENT_FLAG_RETAIN;
+  }
   if (flags != 0) {
     PrintDetails(" unknown_flags=%#x", flags);
   }

test/binary/linking-section.txt

@@ -51,13 +51,16 @@ section("linking") {
   metadata_version[2]
 
   section(LINKING_SEGMENT_INFO) {
-    count[2]
+    count[3]
     str("data1")
     p2align[2]
     flags[1]
     str("data2")
     p2align[3]
     flags[10]
+    str("data3")
+    p2align[2]
+    flags[4]
   }
 
   section(LINKING_INIT_FUNCTIONS) {
@@ -153,9 +156,10 @@ Data[2]:
   - 000000a: 6261 72                                  bar
 Custom:
  - name: "linking"
-  - segment info [count=2]
+  - segment info [count=3]
    - 0: data1 p2align=2 [ STRINGS ]
    - 1: data2 p2align=3 [ TLS unknown_flags=0x8 ]
+   - 2: data3 p2align=2 [ RETAIN ]
   - init functions [count=2]
    - 1: priority=5 <global_sym>
    - 0: priority=6 <func_sym>