[PowerPC] Add an alias for -mregnames so that full register names used in assembly. (#70255)

This option already exists on GCC and so it is being added to LLVM so
that we use the same option as them.

Author: stefanp-synopsys

clang/include/clang/Basic/CodeGenOptions.def

@@ -197,6 +197,7 @@ CODEGENOPT(HIPCorrectlyRoundedDivSqrt, 1, 1) ///< -fno-hip-fp32-correctly-rounde
 CODEGENOPT(HIPSaveKernelArgName, 1, 0) ///< Set when -fhip-kernel-arg-name is enabled.
 CODEGENOPT(UniqueInternalLinkageNames, 1, 0) ///< Internal Linkage symbols get unique names.
 CODEGENOPT(SplitMachineFunctions, 1, 0) ///< Split machine functions using profile information.
+CODEGENOPT(PPCUseFullRegisterNames, 1, 0) ///< Print full register names in assembly
 
 /// When false, this attempts to generate code as if the result of an
 /// overflowing conversion matches the overflowing behavior of a target's native

clang/include/clang/Driver/Options.td

@@ -4789,6 +4789,12 @@ def mrop_protect : Flag<["-"], "mrop-protect">,
     Group<m_ppc_Features_Group>;
 def mprivileged : Flag<["-"], "mprivileged">,
     Group<m_ppc_Features_Group>;
+
+defm regnames : BoolOption<"m", "regnames",
+  CodeGenOpts<"PPCUseFullRegisterNames">, DefaultFalse,
+  PosFlag<SetTrue, [], [ClangOption, CC1Option], "Use full register names when writing assembly output">,
+  NegFlag<SetFalse, [], [ClangOption], "Use only register numbers when writing assembly output">>,
+  Group<m_Group>;
 } // let Flags = [TargetSpecific]
 def maix_small_local_exec_tls : Flag<["-"], "maix-small-local-exec-tls">,
   Group<m_ppc_Features_Group>,

clang/lib/CodeGen/BackendUtil.cpp

@@ -488,6 +488,8 @@ static bool initTargetOptions(DiagnosticsEngine &Diags,
   Options.MCOptions.Argv0 = CodeGenOpts.Argv0;
   Options.MCOptions.CommandLineArgs = CodeGenOpts.CommandLineArgs;
   Options.MCOptions.AsSecureLogFile = CodeGenOpts.AsSecureLogFile;
+  Options.MCOptions.PPCUseFullRegisterNames =
+      CodeGenOpts.PPCUseFullRegisterNames;
   Options.MisExpect = CodeGenOpts.MisExpect;
 
   return true;

clang/lib/Driver/ToolChains/Clang.cpp

@@ -5014,6 +5014,10 @@ void Clang::ConstructJob(Compilation &C, const JobAction &JA,
     Args.AddLastArg(CmdArgs, options::OPT_fthinlto_index_EQ);
   }
 
+  if (Triple.isPPC())
+    Args.addOptInFlag(CmdArgs, options::OPT_mregnames,
+                      options::OPT_mno_regnames);
+
   if (Args.getLastArg(options::OPT_fthin_link_bitcode_EQ))
     Args.AddLastArg(CmdArgs, options::OPT_fthin_link_bitcode_EQ);
 

clang/test/CodeGen/PowerPC/ppc-full-reg-names.c

@@ -0,0 +1,8 @@
+// REQUIRES: powerpc-registered-target
+// RUN: %clang -### -target powerpc64le-unknown-linux-gnu -mcpu=pwr8 -mregnames \
+// RUN:   %s 2>&1 >/dev/null | FileCheck %s --check-prefix=FULLNAMES
+// RUN: %clang -### -target powerpc64le-unknown-linux-gnu -mcpu=pwr8 -mno-regnames \
+// RUN:   %s 2>&1 >/dev/null | FileCheck %s --check-prefix=NOFULLNAMES
+
+// FULLNAMES: -mregnames
+// NOFULLNAMES-NOT: -mregnames

llvm/include/llvm/MC/MCAsmInfo.h

@@ -240,6 +240,9 @@ class MCAsmInfo {
   /// True if the target supports LEB128 directives.
   bool HasLEB128Directives = true;
 
+  /// True if full register names are printed.
+  bool PPCUseFullRegisterNames = false;
+
   //===--- Data Emission Directives -------------------------------------===//
 
   /// This should be set to the directive used to get some number of zero (and
@@ -710,6 +713,9 @@ class MCAsmInfo {
 
   bool hasLEB128Directives() const { return HasLEB128Directives; }
 
+  bool useFullRegisterNames() const { return PPCUseFullRegisterNames; }
+  void setFullRegisterNames(bool V) { PPCUseFullRegisterNames = V; }
+
   const char *getZeroDirective() const { return ZeroDirective; }
   bool doesZeroDirectiveSupportNonZeroValue() const {
     return ZeroDirectiveSupportsNonZeroValue;

llvm/include/llvm/MC/MCTargetOptions.h

@@ -89,6 +89,9 @@ class MCTargetOptions {
   // functions on Darwins.
   bool EmitCompactUnwindNonCanonical : 1;
 
+  // Whether or not to use full register names on PowerPC.
+  bool PPCUseFullRegisterNames : 1;
+
   MCTargetOptions();
 
   /// getABIName - If this returns a non-empty string this represents the

llvm/lib/CodeGen/LLVMTargetMachine.cpp

@@ -81,6 +81,8 @@ void LLVMTargetMachine::initAsmInfo() {
 
   TmpAsmInfo->setRelaxELFRelocations(Options.RelaxELFRelocations);
 
+  TmpAsmInfo->setFullRegisterNames(Options.MCOptions.PPCUseFullRegisterNames);
+
   if (Options.ExceptionModel != ExceptionHandling::None)
     TmpAsmInfo->setExceptionsType(Options.ExceptionModel);
 

llvm/lib/MC/MCAsmInfo.cpp

@@ -67,6 +67,7 @@ MCAsmInfo::MCAsmInfo() {
   UseIntegratedAssembler = true;
   ParseInlineAsmUsingAsmParser = false;
   PreserveAsmComments = true;
+  PPCUseFullRegisterNames = false;
 }
 
 MCAsmInfo::~MCAsmInfo() = default;

llvm/lib/MC/MCTargetOptions.cpp

@@ -19,7 +19,7 @@ MCTargetOptions::MCTargetOptions()
       PreserveAsmComments(true), Dwarf64(false),
       EmitDwarfUnwind(EmitDwarfUnwindType::Default),
       MCUseDwarfDirectory(DefaultDwarfDirectory),
-      EmitCompactUnwindNonCanonical(false) {}
+      EmitCompactUnwindNonCanonical(false), PPCUseFullRegisterNames(false) {}
 
 StringRef MCTargetOptions::getABIName() const {
   return ABIName;

llvm/lib/Target/PowerPC/MCTargetDesc/PPCInstPrinter.cpp

@@ -13,6 +13,7 @@
 #include "MCTargetDesc/PPCInstPrinter.h"
 #include "MCTargetDesc/PPCMCTargetDesc.h"
 #include "MCTargetDesc/PPCPredicates.h"
+#include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCInstrInfo.h"
@@ -596,7 +597,8 @@ void PPCInstPrinter::printTLSCall(const MCInst *MI, unsigned OpNo,
 /// showRegistersWithPercentPrefix - Check if this register name should be
 /// printed with a percentage symbol as prefix.
 bool PPCInstPrinter::showRegistersWithPercentPrefix(const char *RegName) const {
-  if (!FullRegNamesWithPercent || TT.getOS() == Triple::AIX)
+  if ((!FullRegNamesWithPercent && !MAI.useFullRegisterNames()) ||
+      TT.getOS() == Triple::AIX)
     return false;
 
   switch (RegName[0]) {
@@ -613,10 +615,10 @@ bool PPCInstPrinter::showRegistersWithPercentPrefix(const char *RegName) const {
 
 /// getVerboseConditionalRegName - This method expands the condition register
 /// when requested explicitly or targetting Darwin.
-const char *PPCInstPrinter::getVerboseConditionRegName(unsigned RegNum,
-                                                       unsigned RegEncoding)
-                                                       const {
-  if (!FullRegNames)
+const char *
+PPCInstPrinter::getVerboseConditionRegName(unsigned RegNum,
+                                           unsigned RegEncoding) const {
+  if (!FullRegNames && !MAI.useFullRegisterNames())
     return nullptr;
   if (RegNum < PPC::CR0EQ || RegNum > PPC::CR7UN)
     return nullptr;
@@ -636,7 +638,7 @@ const char *PPCInstPrinter::getVerboseConditionRegName(unsigned RegNum,
 // showRegistersWithPrefix - This method determines whether registers
 // should be number-only or include the prefix.
 bool PPCInstPrinter::showRegistersWithPrefix() const {
-  return FullRegNamesWithPercent || FullRegNames;
+  return FullRegNamesWithPercent || FullRegNames || MAI.useFullRegisterNames();
 }
 
 void PPCInstPrinter::printOperand(const MCInst *MI, unsigned OpNo,