[llvm] [object][webassembly] Add support for RUNTIME_PATH to yaml2obj and obj2yaml (PR #126080)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-webassembly

Author: Hood Chatham (hoodmane)

<details>
<summary>Changes</summary>

This is the first step of adding RPATH support for wasm. See corresponding update to the WebAssembly/tool-conventions repo on dynamic linking:
https://github.com/WebAssembly/tool-conventions/pull/246

cc @<!-- -->sbc100 @<!-- -->ryanking13

---
Full diff: https://github.com/llvm/llvm-project/pull/126080.diff


7 Files Affected:

- (modified) llvm/include/llvm/BinaryFormat/Wasm.h (+2) 
- (modified) llvm/include/llvm/ObjectYAML/WasmYAML.h (+1) 
- (modified) llvm/lib/Object/WasmObjectFile.cpp (+4) 
- (modified) llvm/lib/ObjectYAML/WasmEmitter.cpp (+7) 
- (modified) llvm/lib/ObjectYAML/WasmYAML.cpp (+1) 
- (modified) llvm/test/ObjectYAML/wasm/dylink_section.yaml (+2) 
- (modified) llvm/tools/obj2yaml/wasm2yaml.cpp (+1) 


``````````diff
diff --git a/llvm/include/llvm/BinaryFormat/Wasm.h b/llvm/include/llvm/BinaryFormat/Wasm.h
index ede2d692a594916..00782f53a8e13d3 100644
--- a/llvm/include/llvm/BinaryFormat/Wasm.h
+++ b/llvm/include/llvm/BinaryFormat/Wasm.h
@@ -201,6 +201,7 @@ enum : unsigned {
   WASM_DYLINK_NEEDED = 0x2,
   WASM_DYLINK_EXPORT_INFO = 0x3,
   WASM_DYLINK_IMPORT_INFO = 0x4,
+  WASM_DYLINK_RUNTIME_PATH = 0x5,
 };
 
 // Kind codes used in the custom "linking" section in the WASM_COMDAT_INFO
@@ -294,6 +295,7 @@ struct WasmDylinkInfo {
   std::vector<StringRef> Needed; // Shared library dependencies
   std::vector<WasmDylinkImportInfo> ImportInfo;
   std::vector<WasmDylinkExportInfo> ExportInfo;
+  StringRef RuntimePath;
 };
 
 struct WasmProducerInfo {
diff --git a/llvm/include/llvm/ObjectYAML/WasmYAML.h b/llvm/include/llvm/ObjectYAML/WasmYAML.h
index 94ecc2fcfdb536b..2285dd65647689f 100644
--- a/llvm/include/llvm/ObjectYAML/WasmYAML.h
+++ b/llvm/include/llvm/ObjectYAML/WasmYAML.h
@@ -230,6 +230,7 @@ struct DylinkSection : CustomSection {
   std::vector<StringRef> Needed;
   std::vector<DylinkImportInfo> ImportInfo;
   std::vector<DylinkExportInfo> ExportInfo;
+  StringRef RuntimePath;
 };
 
 struct NameSection : CustomSection {
diff --git a/llvm/lib/Object/WasmObjectFile.cpp b/llvm/lib/Object/WasmObjectFile.cpp
index 0f6fd5612f9d82a..5c6b97e0acc8cd8 100644
--- a/llvm/lib/Object/WasmObjectFile.cpp
+++ b/llvm/lib/Object/WasmObjectFile.cpp
@@ -484,6 +484,10 @@ Error WasmObjectFile::parseDylink0Section(ReadContext &Ctx) {
       }
       break;
     }
+    case wasm::WASM_DYLINK_RUNTIME_PATH: {
+      DylinkInfo.RuntimePath = readString(Ctx);
+      break;
+    }
     default:
       LLVM_DEBUG(dbgs() << "unknown dylink.0 sub-section: " << Type << "\n");
       Ctx.Ptr += Size;
diff --git a/llvm/lib/ObjectYAML/WasmEmitter.cpp b/llvm/lib/ObjectYAML/WasmEmitter.cpp
index bd016764f586267..877ece5224959a8 100644
--- a/llvm/lib/ObjectYAML/WasmEmitter.cpp
+++ b/llvm/lib/ObjectYAML/WasmEmitter.cpp
@@ -12,6 +12,7 @@
 //===----------------------------------------------------------------------===//
 //
 
+#include "llvm/BinaryFormat/Wasm.h"
 #include "llvm/Object/Wasm.h"
 #include "llvm/ObjectYAML/ObjectYAML.h"
 #include "llvm/ObjectYAML/yaml2obj.h"
@@ -180,6 +181,12 @@ void WasmWriter::writeSectionContent(raw_ostream &OS,
       writeStringRef(Needed, SubOS);
     SubSection.done();
   }
+  if (Section.RuntimePath.size()) {
+    writeUint8(OS, wasm::WASM_DYLINK_RUNTIME_PATH);
+    raw_ostream &SubOS = SubSection.getStream();
+    writeStringRef(Section.RuntimePath, SubOS);
+    SubSection.done();
+  }
 }
 
 void WasmWriter::writeSectionContent(raw_ostream &OS,
diff --git a/llvm/lib/ObjectYAML/WasmYAML.cpp b/llvm/lib/ObjectYAML/WasmYAML.cpp
index 6af66ba62be1889..d9e93d06dcf273f 100644
--- a/llvm/lib/ObjectYAML/WasmYAML.cpp
+++ b/llvm/lib/ObjectYAML/WasmYAML.cpp
@@ -59,6 +59,7 @@ static void sectionMapping(IO &IO, WasmYAML::DylinkSection &Section) {
   IO.mapRequired("Needed", Section.Needed);
   IO.mapOptional("ImportInfo", Section.ImportInfo);
   IO.mapOptional("ExportInfo", Section.ExportInfo);
+  IO.mapOptional("RuntimePath", Section.RuntimePath);
 }
 
 static void sectionMapping(IO &IO, WasmYAML::NameSection &Section) {
diff --git a/llvm/test/ObjectYAML/wasm/dylink_section.yaml b/llvm/test/ObjectYAML/wasm/dylink_section.yaml
index a43f678c45194b3..cdc094efc345613 100644
--- a/llvm/test/ObjectYAML/wasm/dylink_section.yaml
+++ b/llvm/test/ObjectYAML/wasm/dylink_section.yaml
@@ -11,6 +11,7 @@ Sections:
     TableSize:       1
     TableAlignment:  0
     Needed:          [ libfoo.so, libbar.so ]
+    RuntimePath: $ORIGIN/../lib:$ORIGIN/../../.libs
 ...
 # CHECK: --- !WASM
 # CHECK: FileHeader:
@@ -25,4 +26,5 @@ Sections:
 # CHECK:     Needed:
 # CHECK:       - libfoo.so
 # CHECK:       - libbar.so
+# CHECK:     RuntimePath: '$ORIGIN/../lib:$ORIGIN/../../.libs'
 # CHECK: ...
diff --git a/llvm/tools/obj2yaml/wasm2yaml.cpp b/llvm/tools/obj2yaml/wasm2yaml.cpp
index 9aa7f5abe8dd436..5a9d9a88da2271f 100644
--- a/llvm/tools/obj2yaml/wasm2yaml.cpp
+++ b/llvm/tools/obj2yaml/wasm2yaml.cpp
@@ -61,6 +61,7 @@ WasmDumper::dumpCustomSection(const WasmSection &WasmSec) {
     DylinkSec->TableSize = Info.TableSize;
     DylinkSec->TableAlignment = Info.TableAlignment;
     DylinkSec->Needed = Info.Needed;
+    DylinkSec->RuntimePath = Info.RuntimePath;
     for (const auto &Imp : Info.ImportInfo)
       DylinkSec->ImportInfo.push_back({Imp.Module, Imp.Field, Imp.Flags});
     for (const auto &Exp : Info.ExportInfo)

``````````

</details>


https://github.com/llvm/llvm-project/pull/126080