[WebAssembly] Add languages from debug info to producers section

[sbc100]

llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

152

Can we move all this code to a separate function e.g. writeProducerInfo?

llvm/lib/Target/WebAssembly/LLVMBuild.txt

 has_asmparser = 1
 has_asmprinter = 1
 has_disassembler = 1
 
 [component_1]
 type = Library
 name = WebAssemblyCodeGen
 parent = WebAssembly
-required_libraries = Analysis AsmPrinter CodeGen Core MC Scalar SelectionDAG Support Target TransformUtils WebAssemblyAsmPrinter WebAssemblyDesc WebAssemblyInfo
+required_libraries = Analysis AsmPrinter BinaryFormat CodeGen Core MC Scalar SelectionDAG Support Target TransformUtils WebAssemblyAsmPrinter WebAssemblyDesc WebAssemblyInfo
 add_to_library_groups = WebAssembly

llvm/lib/Target/WebAssembly/WebAssemblyAsmPrinter.cpp

 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/AsmPrinter.h"
 #include "llvm/CodeGen/MachineConstantPool.h"
 #include "llvm/CodeGen/MachineInstr.h"
 #include "llvm/CodeGen/MachineModuleInfoImpls.h"
 #include "llvm/IR/DataLayout.h"
+#include "llvm/IR/DebugInfoMetadata.h"
 #include "llvm/IR/GlobalVariable.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCSectionWasm.h"
 #include "llvm/MC/MCStreamer.h"
 #include "llvm/MC/MCSymbol.h"
 #include "llvm/MC/MCSymbolWasm.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/TargetRegistry.h"
for (const Metadata *MD : Named->operands()) {
       MCSectionWasm *mySection =
           OutContext.getWasmSection(SectionName, SectionKind::getMetadata());
       OutStreamer->SwitchSection(mySection);
       OutStreamer->EmitBytes(Contents->getString());
       OutStreamer->PopSection();
     }
   }
 
+  // Emit producers section if information is available
+  llvm::SmallVector<std::pair<std::string, std::string>, 4> Languages;
+  if (const NamedMDNode *Debug = M.getNamedMetadata("llvm.dbg.cu")) {
+     llvm::SmallSet<StringRef, 4> SeenLanguages;
+    for (size_t i = 0, e = Debug->getNumOperands(); i < e; ++i) {
+      const auto *CU = cast<DICompileUnit>(Debug->getOperand(i));
+      StringRef Language = dwarf::LanguageString(CU->getSourceLanguage());
+      Language.consume_front("DW_LANG_");
+      if (SeenLanguages.insert(Language).second)
+        Languages.emplace_back(Language.str(), "");
+    }
+  }
+
+  llvm::SmallVector<std::pair<std::string, std::string>, 4> Tools;
   if (const NamedMDNode *Ident = M.getNamedMetadata("llvm.ident")) {
     llvm::SmallSet<StringRef, 4> SeenTools;
-    llvm::SmallVector<std::pair<StringRef, StringRef>, 4> Tools;
     for (size_t i = 0, e = Ident->getNumOperands(); i < e; ++i) {
       const auto *S = cast<MDString>(Ident->getOperand(i)->getOperand(0));
       std::pair<StringRef, StringRef> Field = S->getString().split("version");
       StringRef Name = Field.first.trim();
       StringRef Version = Field.second.trim();
-      if (!SeenTools.insert(Name).second)
-        continue;
-      Tools.emplace_back(Name, Version);
+      if (SeenTools.insert(Name).second)
+        Tools.emplace_back(Name.str(), Version.str());
     }
+  }
+
+  int FieldCount = int(!Languages.empty()) + int(!Tools.empty());
+  if (FieldCount != 0) {
     MCSectionWasm *Producers = OutContext.getWasmSection(
         ".custom_section.producers", SectionKind::getMetadata());
     OutStreamer->PushSection();
     OutStreamer->SwitchSection(Producers);
-    OutStreamer->EmitULEB128IntValue(1);
-    OutStreamer->EmitULEB128IntValue(strlen("processed-by"));
-    OutStreamer->EmitBytes("processed-by");
-    OutStreamer->EmitULEB128IntValue(Tools.size());
-    for (auto &Tool : Tools) {
-      OutStreamer->EmitULEB128IntValue(Tool.first.size());
-      OutStreamer->EmitBytes(Tool.first);
-      OutStreamer->EmitULEB128IntValue(Tool.second.size());
-      OutStreamer->EmitBytes(Tool.second);
+    OutStreamer->EmitULEB128IntValue(FieldCount);
+    for (auto &Producers : {std::make_pair("language", &Languages),
+            std::make_pair("processed-by", &Tools)}) {
+      if (Producers.second->empty())
+        continue;
+      OutStreamer->EmitULEB128IntValue(strlen(Producers.first));
+      OutStreamer->EmitBytes(Producers.first);
+      OutStreamer->EmitULEB128IntValue(Producers.second->size());
+      for (auto &Producer : *Producers.second) {
+        OutStreamer->EmitULEB128IntValue(Producer.first.size());
+        OutStreamer->EmitBytes(Producer.first);
+        OutStreamer->EmitULEB128IntValue(Producer.second.size());
+        OutStreamer->EmitBytes(Producer.second);
+      }
     }
     OutStreamer->PopSection();
   }
 }
 
 void WebAssemblyAsmPrinter::EmitConstantPool() {
   assert(MF->getConstantPool()->getConstants().empty() &&
          "WebAssembly disables constant pools");

llvm/test/CodeGen/WebAssembly/custom-sections.ll

 ; RUN: llc < %s -asm-verbose=false | FileCheck %s
 
 ; Test the mechanism for defining user custom sections.
 
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
 !0 = !{ !"red", !"foo" }
 !1 = !{ !"green", !"bar" }
 !2 = !{ !"green", !"qux" }
 !wasm.custom_sections = !{ !0, !1, !2 }
 
 !llvm.ident = !{!3}
 !3 = !{!"clang version 123"}
 
+!llvm.module.flags = !{!4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+
+!llvm.dbg.cu = !{!5}
+!5 = distinct !DICompileUnit(language: DW_LANG_C99, file: !6)
+!6 = !DIFile(filename: "test", directory: "testdir")
+
 ; CHECK:      .section  .custom_section.red,"",@
 ; CHECK-NEXT: .ascii  "foo"
 
 ; CHECK:      .section  .custom_section.green,"",@
 ; CHECK-NEXT: .ascii  "bar"
 
 ; CHECK:      .section  .custom_section.green,"",@
 ; CHECK-NEXT: .ascii  "qux"
 
 ; CHECK:      .section  .custom_section.producers,"",@
+; CHECK-NEXT: .int8 2
+; CHECK-NEXT: .int8 8
+; CHECK-NEXT: .ascii  "language"
 ; CHECK-NEXT: .int8 1
+; CHECK-NEXT: .int8 3
+; CHECK-NEXT: .ascii  "C99"
+; CHECK-NEXT: .int8 0
 ; CHECK-NEXT: .int8 12
 ; CHECK-NEXT: .ascii  "processed-by"
 ; CHECK-NEXT: .int8 1
 ; CHECK-NEXT: .int8 5
 ; CHECK-NEXT: .ascii  "clang"
 ; CHECK-NEXT: .int8 3
 ; CHECK-NEXT: .ascii  "123"

llvm/test/MC/WebAssembly/debug-info.ll

 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
 ; CHECK-NEXT:    Size: 6
 ; CHECK-NEXT:    Offset: 991
 ; CHECK-NEXT:    Name: reloc..debug_line
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:  Section {
 ; CHECK-NEXT:    Type: CUSTOM (0x0)
-; CHECK-NEXT:    Size: 62
+; CHECK-NEXT:    Size: 77
 ; CHECK-NEXT:    Offset: 1021
 ; CHECK-NEXT:    Name: producers
 ; CHECK-NEXT:  }
 ; CHECK-NEXT:]
 ; CHECK-NEXT:Relocations [
 ; CHECK-NEXT:  Section (6) DATA {
 ; CHECK-NEXT:    0x6 R_WEBASSEMBLY_MEMORY_ADDR_I32 myextern 0
 ; CHECK-NEXT:    0xF R_WEBASSEMBLY_TABLE_INDEX_I32 f2