[PowerPC] Add clang option -m[no-]pcrel

[lei]

Summary

Add user-facing front end option to turn off pc-relative memops.
This will be compatible with gcc.

[saghir]

Other than the nit, this looks good to me.

clang/test/Driver/ppc-pcrel.cpp

2

nit: would the first two checks be better off in clang/test/Driver/ppc-features.cpp?

[NeHuang]

LGTM

[lei]

clang/test/Driver/ppc-pcrel.cpp

2

I think it's better to keep all tests for pcrel within this specific pcrel test file.

[saghir]

clang/test/Driver/ppc-pcrel.cpp

2

I don't feel too strongly about where to keep it... there are checks for other target features in ppc-features.cpp so felt pcrel feature check could be put there along with other feature checks.
But feel free to keep them here if you feel that's more appropriate.

[stefanp]

LGTM.

[MaskRay]

arc adds many unneeded tags from Phabricator. You can drop Reviewers: Subscribers: Tags: and the text Summary: with the following script:

arcfilter () {
  arc amend
  git log -1 --pretty=%B | awk '/Reviewers:|Subscribers:/{p=1} /Reviewed By:|Differential Revision:/{p=0} !p && !/^Summary:$/ {sub(/^Summary: /,"");print}' | git commit --amend --date=now -F -
}

Reviewed By: is considered important by some people (https://lists.llvm.org/pipermail/llvm-dev/2020-January/137889.html). You should keep the tag. (I started to use --date=now because some people find author date != committer date annoying. The committer date is usually what people care.))

clang/include/clang/Driver/Options.td

def mwavefrontsize64 : Flag<["-"], "mwavefrontsize64">,
   Group<m_Group>, HelpText<"Wavefront size 64 is used">;
 def mno_wavefrontsize64 : Flag<["-"], "mno-wavefrontsize64">,
   Group<m_Group>, HelpText<"Wavefront size 32 is used">;
 
 def faltivec : Flag<["-"], "faltivec">, Group<f_Group>, Flags<[DriverOption]>;
 def fno_altivec : Flag<["-"], "fno-altivec">, Group<f_Group>, Flags<[DriverOption]>;
 def maltivec : Flag<["-"], "maltivec">, Group<m_ppc_Features_Group>;
 def mno_altivec : Flag<["-"], "mno-altivec">, Group<m_ppc_Features_Group>;
+def mpcrel: Flag<["-"], "mpcrel">, Group<m_ppc_Features_Group>;
+def mno_pcrel: Flag<["-"], "mno-pcrel">, Group<m_ppc_Features_Group>;
 def mspe : Flag<["-"], "mspe">, Group<m_ppc_Features_Group>;
 def mno_spe : Flag<["-"], "mno-spe">, Group<m_ppc_Features_Group>;
 def mvsx : Flag<["-"], "mvsx">, Group<m_ppc_Features_Group>;
 def mno_vsx : Flag<["-"], "mno-vsx">, Group<m_ppc_Features_Group>;
 def msecure_plt : Flag<["-"], "msecure-plt">, Group<m_ppc_Features_Group>;
 def mpower8_vector : Flag<["-"], "mpower8-vector">,
     Group<m_ppc_Features_Group>;
 def mno_power8_vector : Flag<["-"], "mno-power8-vector">,

clang/lib/Basic/Targets/PPC.h

class LLVM_LIBRARY_VISIBILITY PPCTargetInfo : public TargetInfo {
   bool HasP8Crypto = false;
   bool HasDirectMove = false;
   bool HasQPX = false;
   bool HasHTM = false;
   bool HasBPERMD = false;
   bool HasExtDiv = false;
   bool HasP9Vector = false;
   bool HasSPE = false;
+  bool HasPCRelativeMemops = false;
 
 protected:
   std::string ABI;
 
 public:
   PPCTargetInfo(const llvm::Triple &Triple, const TargetOptions &)
       : TargetInfo(Triple) {
     SuitableAlign = 128;

clang/lib/Basic/Targets/PPC.cpp

for (const auto &Feature : Features) {
     } else if (Feature == "+qpx") {
       HasQPX = true;
     } else if (Feature == "+htm") {
       HasHTM = true;
     } else if (Feature == "+float128") {
       HasFloat128 = true;
     } else if (Feature == "+power9-vector") {
       HasP9Vector = true;
+    } else if (Feature == "+pcrelative-memops") {
+      HasPCRelativeMemops = true;
     } else if (Feature == "+spe") {
       HasSPE = true;
       LongDoubleWidth = LongDoubleAlign = 64;
       LongDoubleFormat = &llvm::APFloat::IEEEdouble();
     } else if (Feature == "-hard-float") {
       FloatABI = SoftFloat;
     }
     // TODO: Finish this list and add an assert that we've handled them
bool PPCTargetInfo::initFeatureMap(
 
   return TargetInfo::initFeatureMap(Features, Diags, CPU, FeaturesVec);
 }
 
 // Add any Power10 specific features.
 void PPCTargetInfo::addP10SpecificFeatures(
     llvm::StringMap<bool> &Features) const {
   Features["htm"] = false; // HTM was removed for P10.
+  Features["pcrelative-memops"] = true;
   return;
 }
 
 // Add features specific to the "Future" CPU.
 void PPCTargetInfo::addFutureSpecificFeatures(
     llvm::StringMap<bool> &Features) const {
   return;
 }
 
 bool PPCTargetInfo::hasFeature(StringRef Feature) const {
   return llvm::StringSwitch<bool>(Feature)
       .Case("powerpc", true)
       .Case("altivec", HasAltivec)
       .Case("vsx", HasVSX)
       .Case("power8-vector", HasP8Vector)
       .Case("crypto", HasP8Crypto)
       .Case("direct-move", HasDirectMove)
       .Case("qpx", HasQPX)
       .Case("htm", HasHTM)
       .Case("bpermd", HasBPERMD)
       .Case("extdiv", HasExtDiv)
       .Case("float128", HasFloat128)
       .Case("power9-vector", HasP9Vector)
+      .Case("pcrelative-memops", HasPCRelativeMemops)
       .Case("spe", HasSPE)
       .Default(false);
 }
 
 void PPCTargetInfo::setFeatureEnabled(llvm::StringMap<bool> &Features,
                                       StringRef Name, bool Enabled) const {
   if (Enabled) {
     // If we're enabling any of the vsx based features then enable vsx and
     // altivec. We'll diagnose any problems later.
     bool FeatureHasVSX = llvm::StringSwitch<bool>(Name)
                              .Case("vsx", true)
                              .Case("direct-move", true)
                              .Case("power8-vector", true)
                              .Case("power9-vector", true)
                              .Case("float128", true)
                              .Default(false);
     if (FeatureHasVSX)
       Features["vsx"] = Features["altivec"] = true;
     if (Name == "power9-vector")
       Features["power8-vector"] = true;
+    if (Name == "pcrel")
+      Features["pcrelative-memops"] = true;
+    else
       Features[Name] = true;
   } else {
     // If we're disabling altivec or vsx go ahead and disable all of the vsx
     // features.
     if ((Name == "altivec") || (Name == "vsx"))
       Features["vsx"] = Features["direct-move"] = Features["power8-vector"] =
           Features["float128"] = Features["power9-vector"] = false;
     if (Name == "power8-vector")
       Features["power9-vector"] = false;
+    if (Name == "pcrel")
+      Features["pcrelative-memops"] = false;
+    else
       Features[Name] = false;
   }
 }
 
 const char *const PPCTargetInfo::GCCRegNames[] = {
     "r0",  "r1",     "r2",   "r3",      "r4",      "r5",  "r6",  "r7",  "r8",
     "r9",  "r10",    "r11",  "r12",     "r13",     "r14", "r15", "r16", "r17",
     "r18", "r19",    "r20",  "r21",     "r22",     "r23", "r24", "r25", "r26",
     "r27", "r28",    "r29",  "r30",     "r31",     "f0",  "f1",  "f2",  "f3",

clang/test/Driver/ppc-pcrel.cpp

+// RUN: %clang -target powerpc64-unknown-linux-gnu %s -### -mcpu=pwr10 -mpcrel -o %t.o 2>&1 | FileCheck -check-prefix=CHECK-PCREL %s
+// RUN: %clang -target powerpc64-unknown-linux-gnu %s -### -mcpu=pwr10 -mno-pcrel -o %t.o 2>&1 | FileCheck -check-prefix=CHECK-NOPCREL %s
+// CHECK-NOPCREL: "-target-feature" "-pcrel"
+// CHECK-PCREL: "-target-feature" "+pcrel"
+
+// RUN: %clang -target powerpc64-unknown-linux-gnu -mcpu=pwr10 -emit-llvm -S %s -o - | grep "attributes.*+pcrelative-memops"
+// RUN: %clang -target powerpc64-unknown-linux-gnu -mcpu=pwr10 -mpcrel -emit-llvm -S %s -o - | grep "attributes.*+pcrelative-memops"
+// RUN: %clang -target powerpc64-unknown-linux-gnu -mcpu=pwr10 -mno-pcrel -emit-llvm -S %s -o - | grep "attributes.*\-pcrelative-memops"
+
+int main(int argc, char *argv[]) {
+  return 0;
+}