all: switch to LLVM 16

This commit adds support for LLVM 16 and switches to it by default. That
means three LLVM versions are supported at the same time: LLVM 14, 15,
and 16.

This commit includes work by QuLogic:

  * Part of this work was based on a PR by QuLogic:
    https://github.com/tinygo-org/tinygo/pull/3649
    But I also had parts of this already implemented in an old branch I
    already made for LLVM 16.
  * QuLogic also provided a CGo fix here, which is also incorporated in
    this commit:
    https://github.com/tinygo-org/tinygo/pull/3869

The difference with the original PR by QuLogic is that this commit is
more complete:
  * It switches to LLVM 16 by default.
  * It updates some things to also make it work with a self-built LLVM.
  * It fixes the CGo bug in a slightly different way, and also fixes
    another one not included in the original PR.
  * It does not keep compiler tests passing on older LLVM versions. I
    have found this to be quite burdensome and therefore don't generally
    do this - the smoke tests should hopefully catch most regressions.

builder/cc1as.cpp

@@ -56,6 +56,7 @@
 #include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 #include <memory>
+#include <optional>
 #include <system_error>
 using namespace clang;
 using namespace clang::driver;
@@ -103,6 +104,14 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
   Opts.Triple = llvm::Triple::normalize(Args.getLastArgValue(OPT_triple));
   if (Arg *A = Args.getLastArg(options::OPT_darwin_target_variant_triple))
     Opts.DarwinTargetVariantTriple = llvm::Triple(A->getValue());
+  if (Arg *A = Args.getLastArg(OPT_darwin_target_variant_sdk_version_EQ)) {
+    VersionTuple Version;
+    if (Version.tryParse(A->getValue()))
+      Diags.Report(diag::err_drv_invalid_value)
+          << A->getAsString(Args) << A->getValue();
+    else
+      Opts.DarwinTargetVariantSDKVersion = Version;
+  }
 
   Opts.CPU = std::string(Args.getLastArgValue(OPT_target_cpu));
   Opts.Features = Args.getAllArgValues(OPT_target_feature);
@@ -122,11 +131,12 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
     Opts.CompressDebugSections =
         llvm::StringSwitch<llvm::DebugCompressionType>(A->getValue())
             .Case("none", llvm::DebugCompressionType::None)
-            .Case("zlib", llvm::DebugCompressionType::Z)
+            .Case("zlib", llvm::DebugCompressionType::Zlib)
+            .Case("zstd", llvm::DebugCompressionType::Zstd)
             .Default(llvm::DebugCompressionType::None);
   }
 
-  Opts.RelaxELFRelocations = Args.hasArg(OPT_mrelax_relocations);
+  Opts.RelaxELFRelocations = !Args.hasArg(OPT_mrelax_relocations_no);
   if (auto *DwarfFormatArg = Args.getLastArg(OPT_gdwarf64, OPT_gdwarf32))
     Opts.Dwarf64 = DwarfFormatArg->getOption().matches(OPT_gdwarf64);
   Opts.DwarfVersion = getLastArgIntValue(Args, OPT_dwarf_version_EQ, 2, Diags);
@@ -189,6 +199,7 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
   Opts.NoExecStack = Args.hasArg(OPT_mno_exec_stack);
   Opts.FatalWarnings = Args.hasArg(OPT_massembler_fatal_warnings);
   Opts.NoWarn = Args.hasArg(OPT_massembler_no_warn);
+  Opts.NoTypeCheck = Args.hasArg(OPT_mno_type_check);
   Opts.RelocationModel =
       std::string(Args.getLastArgValue(OPT_mrelocation_model, "pic"));
   Opts.TargetABI = std::string(Args.getLastArgValue(OPT_target_abi));
@@ -214,6 +225,8 @@ bool AssemblerInvocation::CreateFromArgs(AssemblerInvocation &Opts,
             .Case("default", EmitDwarfUnwindType::Default);
   }
 
+  Opts.AsSecureLogFile = Args.getLastArgValue(OPT_as_secure_log_file);
+
   return Success;
 }
 
@@ -265,6 +278,7 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
 
   MCTargetOptions MCOptions;
   MCOptions.EmitDwarfUnwind = Opts.EmitDwarfUnwind;
+  MCOptions.AsSecureLogFile = Opts.AsSecureLogFile;
 
   std::unique_ptr<MCAsmInfo> MAI(
       TheTarget->createMCAsmInfo(*MRI, Opts.Triple, MCOptions));
@@ -314,6 +328,8 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
       TheTarget->createMCObjectFileInfo(Ctx, PIC));
   if (Opts.DarwinTargetVariantTriple)
     MOFI->setDarwinTargetVariantTriple(*Opts.DarwinTargetVariantTriple);
+  if (!Opts.DarwinTargetVariantSDKVersion.empty())
+    MOFI->setDarwinTargetVariantSDKVersion(Opts.DarwinTargetVariantSDKVersion);
   Ctx.setObjectFileInfo(MOFI.get());
 
   if (Opts.SaveTemporaryLabels)
@@ -353,6 +369,7 @@ static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
 
   MCOptions.MCNoWarn = Opts.NoWarn;
   MCOptions.MCFatalWarnings = Opts.FatalWarnings;
+  MCOptions.MCNoTypeCheck = Opts.NoTypeCheck;
   MCOptions.ABIName = Opts.TargetABI;
 
   // FIXME: There is a bit of code duplication with addPassesToEmitFile.