Auto merge of rust-lang#135763 - nikic:llvm-20, r=cuviper

Update to LLVM 20

LLVM 20 GA is scheduled for March 11th. Rust 1.87 will be stable on May 15th.

* [x] rust-lang#135764
* [x] rust-lang#136134
* [x] rust-lang/compiler-builtins#752
* [x] llvm/llvm-project#125287
* [x] rust-lang#136537
* [x] rust-lang#136895
* [x] Wait for beta branch (Feb 14).

Tested: host-x86_64, host-aarch64, apple, mingw, msvc

Author: bors

.gitmodules

@@ -29,7 +29,7 @@
 [submodule "src/llvm-project"]
 	path = src/llvm-project
 	url = https://github.com/rust-lang/llvm-project.git
-	branch = rustc/19.1-2024-12-03
+	branch = rustc/20.1-2025-02-13
 	shallow = true
 [submodule "src/doc/embedded-book"]
 	path = src/doc/embedded-book

compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp

@@ -22,6 +22,7 @@
 #include "llvm/Passes/StandardInstrumentations.h"
 #include "llvm/Support/CBindingWrapping.h"
 #include "llvm/Support/FileSystem.h"
+#include "llvm/Support/Program.h"
 #include "llvm/Support/TimeProfiler.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Target/TargetMachine.h"
@@ -472,16 +473,19 @@ extern "C" LLVMTargetMachineRef LLVMRustCreateTargetMachine(
     assert(ArgsCstrBuff[ArgsCstrBuffLen - 1] == '\0');
     auto Arg0 = std::string(ArgsCstrBuff);
     buffer_offset = Arg0.size() + 1;
-    auto ArgsCppStr = std::string(ArgsCstrBuff + buffer_offset,
-                                  ArgsCstrBuffLen - buffer_offset);
-    auto i = 0;
-    while (i != std::string::npos) {
-      i = ArgsCppStr.find('\0', i + 1);
-      if (i != std::string::npos)
-        ArgsCppStr.replace(i, 1, " ");
+
+    std::string CommandlineArgs;
+    raw_string_ostream OS(CommandlineArgs);
+    ListSeparator LS(" ");
+    for (StringRef Arg : split(StringRef(ArgsCstrBuff + buffer_offset,
+                                         ArgsCstrBuffLen - buffer_offset),
+                               '\0')) {
+      OS << LS;
+      sys::printArg(OS, Arg, /*Quote=*/true);
     }
+    OS.flush();
     Options.MCOptions.Argv0 = Arg0;
-    Options.MCOptions.CommandlineArgs = ArgsCppStr;
+    Options.MCOptions.CommandlineArgs = CommandlineArgs;
 #else
     int buffer_offset = 0;
     assert(ArgsCstrBuff[ArgsCstrBuffLen - 1] == '\0');