[WebAssembly] Add more test coverage for reloctions against section symbols

The only known user of this relocation type and symbol type is
the debug info sections, but we were not testing the `--relocatable`
output path.

This change adds a minimal test case to cover relocations against
section symbols includes `--relocatable` output.

Differential Revision: https://reviews.llvm.org/D61623

llvm-svn: 360110

3 files changed, 53 insertions, 6 deletions

diff --git a/lld/test/wasm/section-symbol-relocs.yaml b/lld/test/wasm/section-symbol-relocs.yaml
new file mode 100644
index 00000000000..ad292e39f99
--- /dev/null
+++ b/lld/test/wasm/section-symbol-relocs.yaml
@@ -0,0 +1,51 @@
+# RUN: yaml2obj %s -o %t.o
+# RUN: llc -filetype=obj  %S/Inputs/custom.ll -o %t2.o
+# RUN: wasm-ld --no-entry -o - %t2.o %t.o | obj2yaml | FileCheck %s
+# RUN: wasm-ld -r --no-entry -o - %t2.o %t.o | obj2yaml | FileCheck %s -check-prefix=RELOC
+
+--- !WASM
+FileHeader:
+  Version:         0x00000001
+Sections:
+  - Type:            CUSTOM
+    Name:            green
+    Payload:         'AA0000000000000000'
+    Relocations:
+      - Type:            R_WASM_SECTION_OFFSET_I32
+        Index:           0
+        Offset:          0x00000001
+      - Type:            R_WASM_SECTION_OFFSET_I32
+        Index:           1
+        Offset:          0x00000005
+  - Type:            CUSTOM
+    Name:            red
+    Payload:         'BB0000000000000000'
+  - Type:            CUSTOM
+    Name:            linking
+    Version:         2
+    SymbolTable:
+      - Index:           0
+        Kind:            SECTION
+        Section:         0
+        Flags:           [ BINDING_LOCAL ]
+      - Index:           1
+        Kind:            SECTION
+        Section:         1
+        Flags:           [ BINDING_LOCAL ]
+...
+
+# CHECK:        Name:            green
+# CHECK-NEXT:   Payload:         626172717578AA0600000003000000
+# CHECK:        Name:            red
+# CHECK-NEXT:   Payload:         666F6FBB0000000000000000
+
+# RELOC:        Relocations:
+# RELOC-NEXT:       - Type:            R_WASM_SECTION_OFFSET_I32
+# RELOC-NEXT:         Index:           0
+# RELOC-NEXT:         Offset:          0x00000007
+# RELOC-NEXT:         Addend:          6
+# RELOC-NEXT:       - Type:            R_WASM_SECTION_OFFSET_I32
+# RELOC-NEXT:         Index:           1
+# RELOC-NEXT:         Offset:          0x0000000B
+# RELOC-NEXT:         Addend:          3
+# RELOC-NEXT:    Name:            green
diff --git a/llvm/lib/ObjectYAML/WasmYAML.cpp b/llvm/lib/ObjectYAML/WasmYAML.cpp
index 214aa1c7808..88491d955c4 100644
--- a/llvm/lib/ObjectYAML/WasmYAML.cpp
+++ b/llvm/lib/ObjectYAML/WasmYAML.cpp
@@ -484,7 +484,8 @@ void MappingTraits<WasmYAML::SymbolInfo>::mapping(IO &IO,
                                                   WasmYAML::SymbolInfo &Info) {
   IO.mapRequired("Index", Info.Index);
   IO.mapRequired("Kind", Info.Kind);
-  IO.mapRequired("Name", Info.Name);
+  if (Info.Kind != wasm::WASM_SYMBOL_TYPE_SECTION)
+    IO.mapRequired("Name", Info.Name);
   IO.mapRequired("Flags", Info.Flags);
   if (Info.Kind == wasm::WASM_SYMBOL_TYPE_FUNCTION) {
     IO.mapRequired("Function", Info.ElementIndex);
diff --git a/llvm/tools/yaml2obj/yaml2wasm.cpp b/llvm/tools/yaml2obj/yaml2wasm.cpp
index cd07a30b748..758c498bd35 100644
--- a/llvm/tools/yaml2obj/yaml2wasm.cpp
+++ b/llvm/tools/yaml2obj/yaml2wasm.cpp
@@ -532,11 +532,6 @@ int WasmWriter::writeRelocSection(raw_ostream &OS, WasmYAML::Section &Sec,
     break;
   case wasm::WASM_SEC_CUSTOM: {
     auto CustomSection = dyn_cast<WasmYAML::CustomSection>(&Sec);
-    if (!CustomSection->Name.startswith(".debug_")) {
-      llvm_unreachable("not yet implemented (only for debug sections)");
-      return 1;
-    }
-
     writeStringRef(("reloc." + CustomSection->Name).str(), OS);
     break;
   }