Revert "[Demangle] make llvm::demangle take std::string_view rather than const std::string&"

This reverts commit c117c2c8ba4afd45a006043ec6dd858652b2ffcc.

itaniumDemangle calls std::strlen with the results of
std::string_view::data() which may not be NUL-terminated. This causes
lld/test/wasm/why-extract.s  to fail when "expensive checks" are enabled
via -DLLVM_ENABLE_EXPENSIVE_CHECKS=ON. See D149675 for further
discussion. Back this out until the individual demanglers are converted
to use std::string_view.

5 files changed, 13 insertions, 14 deletions

diff --git a/lld/COFF/Symbols.cpp b/lld/COFF/Symbols.cpp
index f4efcf2266cd..c042386e0106 100644
--- a/lld/COFF/Symbols.cpp
+++ b/lld/COFF/Symbols.cpp
@@ -38,9 +38,9 @@ static std::string maybeDemangleSymbol(const COFFLinkerContext &ctx,
     StringRef demangleInput = prefixless;
     if (ctx.config.machine == I386)
       demangleInput.consume_front("_");
-    std::string demangled = demangle(demangleInput);
+    std::string demangled = demangle(demangleInput.str());
     if (demangled != demangleInput)
-      return prefix + demangled;
+      return prefix + demangle(demangleInput.str());
     return (prefix + prefixless).str();
   }
   return std::string(symName);
diff --git a/lld/ELF/SymbolTable.cpp b/lld/ELF/SymbolTable.cpp
index c5ef6d3f0cbf..f09d0d7f9095 100644
--- a/lld/ELF/SymbolTable.cpp
+++ b/lld/ELF/SymbolTable.cpp
@@ -145,16 +145,13 @@ StringMap<SmallVector<Symbol *, 0>> &SymbolTable::getDemangledSyms() {
       if (canBeVersioned(*sym)) {
         StringRef name = sym->getName();
         size_t pos = name.find('@');
-        std::string substr;
         if (pos == std::string::npos)
-          demangled = demangle(name);
-        else if (pos + 1 == name.size() || name[pos + 1] == '@') {
-          substr = name.substr(0, pos);
-          demangled = demangle(substr);
-        } else {
-          substr = name.substr(0, pos);
-          demangled = (demangle(substr) + name.substr(pos)).str();
-        }
+          demangled = demangle(name.str());
+        else if (pos + 1 == name.size() || name[pos + 1] == '@')
+          demangled = demangle(name.substr(0, pos).str());
+        else
+          demangled =
+              (demangle(name.substr(0, pos).str()) + name.substr(pos)).str();
         (*demangledSyms)[demangled].push_back(sym);
       }
   }
diff --git a/lld/ELF/Symbols.cpp b/lld/ELF/Symbols.cpp
index 840385aabea3..62a8a3c30664 100644
--- a/lld/ELF/Symbols.cpp
+++ b/lld/ELF/Symbols.cpp
@@ -45,7 +45,9 @@ LLVM_ATTRIBUTE_UNUSED static inline void assertSymbols() {
 
 // Returns a symbol for an error message.
 static std::string maybeDemangleSymbol(StringRef symName) {
-  return elf::config->demangle ? demangle(symName.str()) : symName.str();
+  if (elf::config->demangle)
+    return demangle(symName.str());
+  return symName.str();
 }
 
 std::string lld::toString(const elf::Symbol &sym) {
diff --git a/lld/MachO/Symbols.cpp b/lld/MachO/Symbols.cpp
index 660826edc4f8..cb3b271a1912 100644
--- a/lld/MachO/Symbols.cpp
+++ b/lld/MachO/Symbols.cpp
@@ -32,7 +32,7 @@ static_assert(sizeof(SymbolUnion) == sizeof(Defined),
 static std::string maybeDemangleSymbol(StringRef symName) {
   if (config->demangle) {
     symName.consume_front("_");
-    return demangle(symName);
+    return demangle(symName.str());
   }
   return symName.str();
 }
diff --git a/lld/wasm/Symbols.cpp b/lld/wasm/Symbols.cpp
index 2adf72b6965c..567ff49dfa44 100644
--- a/lld/wasm/Symbols.cpp
+++ b/lld/wasm/Symbols.cpp
@@ -35,7 +35,7 @@ std::string maybeDemangleSymbol(StringRef name) {
   if (name == "__main_argc_argv")
     return "main";
   if (wasm::config->demangle)
-    return demangle(name);
+    return demangle(name.str());
   return name.str();
 }