[Xtensa] Implement esp32 psram cache fixes.

Author: andreisfr

clang/include/clang/Driver/Options.td

@@ -176,6 +176,8 @@ def m_x86_Features_Group : OptionGroup<"<x86 features group>">,
                            Group<m_Group>, Flags<[CoreOption]>, DocName<"X86">;
 def m_riscv_Features_Group : OptionGroup<"<riscv features group>">,
                              Group<m_Group>, DocName<"RISCV">;
+def m_xtensa_Features_Group : OptionGroup<"<xtensa features group>">,
+                              Group<m_Group>, Flags<[CoreOption]>, DocName<"Xtensa">;
 
 def m_libc_Group : OptionGroup<"<m libc group>">, Group<m_mips_Features_Group>,
                    Flags<[HelpHidden]>;
@@ -4255,6 +4257,13 @@ def mno_retpoline_external_thunk : Flag<["-"], "mno-retpoline-external-thunk">,
 def mvzeroupper : Flag<["-"], "mvzeroupper">, Group<m_x86_Features_Group>;
 def mno_vzeroupper : Flag<["-"], "mno-vzeroupper">, Group<m_x86_Features_Group>;
 
+// Xtensa feature flags
+def malways_memw : Flag<["-"], "malways-memw">, Group<m_xtensa_Features_Group>;
+def mfix_esp32_psram_cache_issue : Flag<["-"], "mfix-esp32-psram-cache-issue">, Group<m_xtensa_Features_Group>;
+def mfix_esp32_psram_cache_strategy_EQ : Joined<["-"], "mfix-esp32-psram-cache-strategy=">, Group<m_xtensa_Features_Group>,
+    HelpText<" Psram cache fix strategies : memw, nops">,
+    Values<"memw, nops">;
+
 // These are legacy user-facing driver-level option spellings. They are always
 // aliases for options that are spelled using the more common Unix / GNU flag
 // style of double-dash and equals-joined flags.

clang/lib/Driver/ToolChains/Clang.cpp

@@ -1728,6 +1728,10 @@ void Clang::RenderTargetOptions(const llvm::Triple &EffectiveTriple,
   case llvm::Triple::ve:
     AddVETargetArgs(Args, CmdArgs);
     break;
+
+  case llvm::Triple::xtensa:
+    AddXtensaTargetArgs(Args, CmdArgs);
+    break;
   }
 }
 
@@ -2276,6 +2280,34 @@ void Clang::AddVETargetArgs(const ArgList &Args, ArgStringList &CmdArgs) const {
   CmdArgs.push_back("hard");
 }
 
+void Clang::AddXtensaTargetArgs(const ArgList &Args,
+                                ArgStringList &CmdArgs) const {
+  const Driver &D = getToolChain().getDriver();
+
+  if (Args.getLastArg(options::OPT_malways_memw) != nullptr) {
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("-malways-memw");
+  }
+
+  if (Args.getLastArg(options::OPT_mfix_esp32_psram_cache_issue) != nullptr) {
+    CmdArgs.push_back("-mllvm");
+    CmdArgs.push_back("-mfix-esp32-psram-cache-issue");
+
+    if (Arg *A =
+            Args.getLastArg(options::OPT_mfix_esp32_psram_cache_strategy_EQ)) {
+      StringRef Value = A->getValue();
+      if (Value == "memw" || Value == "nops") {
+        CmdArgs.push_back("-mllvm");
+        CmdArgs.push_back(
+            Args.MakeArgString("-mfix-esp32-psram-cache-strategy=" + Value));
+      } else {
+        D.Diag(diag::err_drv_unsupported_option_argument)
+            << A->getOption().getName() << Value;
+      }
+    }
+  }
+}
+
 void Clang::DumpCompilationDatabase(Compilation &C, StringRef Filename,
                                     StringRef Target, const InputInfo &Output,
                                     const InputInfo &Input, const ArgList &Args) const {

clang/lib/Driver/ToolChains/Clang.h

@@ -75,6 +75,8 @@ class LLVM_LIBRARY_VISIBILITY Clang : public Tool {
                                 llvm::opt::ArgStringList &CmdArgs) const;
   void AddVETargetArgs(const llvm::opt::ArgList &Args,
                        llvm::opt::ArgStringList &CmdArgs) const;
+  void AddXtensaTargetArgs(const llvm::opt::ArgList &Args,
+                       llvm::opt::ArgStringList &CmdArgs) const;
 
   enum RewriteKind { RK_None, RK_Fragile, RK_NonFragile };
 

clang/lib/Driver/ToolChains/Xtensa.cpp

@@ -107,16 +107,32 @@ XtensaToolChain::XtensaToolChain(const Driver &D, const llvm::Triple &Triple,
       IsIntegratedAsm = false;
   }
 
+  bool IsESP32 = XtensaToolChain::GetTargetCPUVersion(Args).equals("esp32");
   Multilibs.push_back(Multilib());
+  if (IsESP32)
+    Multilibs.push_back(Multilib("esp32-psram", {}, {}, 2)
+                            .flag("+mfix-esp32-psram-cache-issue"));
 
   Multilibs.push_back(
       Multilib("no-rtti", {}, {}, 1).flag("+fno-rtti").flag("-frtti"));
 
+  if (IsESP32)
+    Multilibs.push_back(Multilib("esp32-psram/no-rtti", {}, {}, 3)
+                            .flag("+fno-rtti")
+                            .flag("-frtti")
+                            .flag("+mfix-esp32-psram-cache-issue"));
+
   Multilib::flags_list Flags;
   addMultilibFlag(
       Args.hasFlag(options::OPT_frtti, options::OPT_fno_rtti, false), "frtti",
       Flags);
 
+  if (IsESP32)
+    addMultilibFlag(Args.hasFlag(options::OPT_mfix_esp32_psram_cache_issue,
+                                 options::OPT_mfix_esp32_psram_cache_issue,
+                                 false),
+                    "mfix-esp32-psram-cache-issue", Flags);
+
   Multilibs.select(Flags, SelectedMultilib);
 
   const std::string Slash = XtensaGCCToolchain.Slash;

llvm/lib/Target/Xtensa/CMakeLists.txt

@@ -17,6 +17,7 @@ add_public_tablegen_target(XtensaCommonTableGen)
 add_llvm_target(XtensaCodeGen
   XtensaAsmPrinter.cpp
   XtensaConstantPoolValue.cpp
+  XtensaESP32PSRAMFix.cpp
   XtensaFixupHWLoops.cpp
   XtensaFrameLowering.cpp
   XtensaHardwareLoops.cpp

llvm/lib/Target/Xtensa/Xtensa.h

@@ -28,5 +28,6 @@ FunctionPass *createXtensaISelDag(XtensaTargetMachine &TM,
 FunctionPass *createXtensaSizeReductionPass();
 FunctionPass *createXtensaHardwareLoops();
 FunctionPass *createXtensaFixupHwLoops();
+FunctionPass *createXtensaPSRAMCacheFixPass();
 } // namespace llvm
 #endif /* LLVM_LIB_TARGET_XTENSA_XTENSA_H */