[mips] Improve handling of -fno-[pic/PIC] option

[abeserminji]

Summary

• On N64 ABI, -mno-abicalls is needed to disable PIC. Warning is reported when only -fno-pic/-fno-PIC is used. This is how GCC behaves.
• An error is reported when -fno-pic or -fno-PIC is used in combination with -mabicalls.

Depends on D44381.

[sdardis]

A quick comment on the error message, inlined. It's about the quality of the diagnostics.

include/clang/Basic/DiagnosticDriverKinds.td

339–340

Can you fine tune this error message to say:

"ignoring '-fno-pic' option as it cannot be used with explicit use of -mabicalls and the N64 ABI" when -mabicalls is used on the commandline and:

"ignoring '-fno-pic' option as it cannot be used with implicit use of -mabicalls and the N64 ABI" when -mno-abicalls and -mabicalls are not present.

You should also report the precise pic/PIC/pie/PIE option used in the error message. You should be able to get it from the argument directly: http://llvm.org/doxygen/classllvm_1_1opt_1_1Arg.html

[abeserminji]

Comments resolved.

[sdardis]

include/clang/Basic/DiagnosticDriverKinds.td

340

Use the %select{optionA|optionB|..|optionZ}$NUM operator here like:

"cannot be used with the %select{explicit|implicit}1 usage of -mabicalls and the N64 ABI"

Which eliminates the need for two separate warnings.

lib/Driver/ToolChains/Arch/Mips.cpp

242–250

Then all of this can be simplified.

[abeserminji]

Comments resolved.

include/clang/Basic/DiagnosticDriverKinds.td

340

Thanks for the hint. I simplified it now.

[sdardis]

LGTM, with a touch up of the error message to match the others we have regarding -mabicalls. Some other minor nits inlined.

include/clang/Basic/DiagnosticDriverKinds.td

340

Just saw the error messages above; so for style, you should reformat the message to be of the form "ignoring '%0' option as it cannt be used with %select{|implicit usage of}1-mabicalls and the N64 ABI".

This way all the error messages are consistent.

lib/Driver/ToolChains/CommonArgs.cpp

1024

Nit: "When targeting the N64 ABI, PIC is the default, except in the case when the -mno-abicalls option is used."

test/Driver/mips-abicalls-warning.c

2–12

Add some checks for -fno-pie, -fno-PIE.

[abeserminji]

Comments resolved.

include/clang/Basic/DiagnosticDriverKinds.td

 def warn_drv_unsupported_gpopt : Warning<
   "ignoring '-mgpopt' option as it cannot be used with %select{|the implicit"
   " usage of }0-mabicalls">,
   InGroup<UnsupportedGPOpt>;
 def warn_drv_unsupported_longcalls : Warning<
   "ignoring '-mlong-calls' option as it is not currently supported with "
   "%select{|the implicit usage of }0-mabicalls">,
   InGroup<OptionIgnored>;
-def warn_drv_unsupported_abicalls : Warning<
-  "ignoring '-mabicalls' option as it cannot be used with "
-  "non position-independent code and the N64 ABI">,
+def warn_drv_unsupported_pic_with_explicit_mabicalls : Warning<
+  "ignoring '%0' option as it cannot be used with "
+  "explicit use of -mabicalls and the N64 ABI">,
   InGroup<OptionIgnored>;
+def warn_drv_unsupported_pic_with_implicit_mabicalls : Warning<
+  "ignoring '%0' option as it cannot be used with "
+  "implicit use of -mabicalls and the N64 ABI">,
+  InGroup<OptionIgnored>;
+def err_drv_unsupported_noabicalls_pic : Error<
+  "position-independent code requires ‘-mabicalls’">;
 def err_drv_unsupported_indirect_jump_opt : Error<
   "'-mindirect-jump=%0' is unsupported with the '%1' architecture">;
 def err_drv_unknown_indirect_jump_opt : Error<
   "unknown '-mindirect-jump=' option '%0'">;
 
 def warn_drv_unable_to_find_directory_expected : Warning<
   "unable to find %0 directory, expected to be in '%1'">,
   InGroup<InvalidOrNonExistentDirectory>, DefaultIgnore;

lib/Driver/ToolChains/Arch/Mips.cpp

void mips::getMIPSTargetFeatures(const Driver &D, const llvm::Triple &Triple,
   // The combinations for N64 are:
   // a) Static without abicalls and 64bit symbols.
   // b) Static with abicalls and 32bit symbols.
   // c) PIC with abicalls and 64bit symbols.
 
   // For case (a) we need to add +noabicalls for N64.
 
   bool IsN64 = ABIName == "64";
+  bool IsPIC = false;
   bool NonPIC = false;
 
   Arg *LastPICArg = Args.getLastArg(options::OPT_fPIC, options::OPT_fno_PIC,
                                     options::OPT_fpic, options::OPT_fno_pic,
                                     options::OPT_fPIE, options::OPT_fno_PIE,
                                     options::OPT_fpie, options::OPT_fno_pie);
   if (LastPICArg) {
     Option O = LastPICArg->getOption();
     NonPIC =
         (O.matches(options::OPT_fno_PIC) || O.matches(options::OPT_fno_pic) ||
          O.matches(options::OPT_fno_PIE) || O.matches(options::OPT_fno_pie));
+    IsPIC =
+        (O.matches(options::OPT_fPIC) || O.matches(options::OPT_fpic) ||
+         O.matches(options::OPT_fPIE) || O.matches(options::OPT_fpie));
   }
 
   bool UseAbiCalls = false;
 
   Arg *ABICallsArg =
       Args.getLastArg(options::OPT_mabicalls, options::OPT_mno_abicalls);
   UseAbiCalls =
       !ABICallsArg || ABICallsArg->getOption().matches(options::OPT_mabicalls);
 
-  if (UseAbiCalls && IsN64 && NonPIC) {
-    D.Diag(diag::warn_drv_unsupported_abicalls);
-    UseAbiCalls = false;
+  if (IsN64 && NonPIC) {
+    if (!ABICallsArg) {
+      D.Diag(diag::warn_drv_unsupported_pic_with_implicit_mabicalls)
+          << LastPICArg->getAsString(Args);
+      NonPIC = false;
+    } else if (UseAbiCalls) {
+      D.Diag(diag::warn_drv_unsupported_pic_with_explicit_mabicalls)
+          << LastPICArg->getAsString(Args);
+      NonPIC = false;
+    }
+  }
+
+  if (ABICallsArg && !UseAbiCalls && IsPIC) {
+    D.Diag(diag::err_drv_unsupported_noabicalls_pic);
   }
 
   if (!UseAbiCalls)
     Features.push_back("+noabicalls");
   else
     Features.push_back("-noabicalls");
 
   if (Arg *A = Args.getLastArg(options::OPT_mlong_calls,

lib/Driver/ToolChains/CommonArgs.cpp

tools::ParsePICArgs(const ToolChain &ToolChain, const ArgList &Args) {
   // ROPI and RWPI are not compatible with PIC or PIE.
   if ((ROPI || RWPI) && (PIC || PIE))
     ToolChain.getDriver().Diag(diag::err_drv_ropi_rwpi_incompatible_with_pic);
 
   if (Triple.getArch() == llvm::Triple::mips ||
        Triple.getArch() == llvm::Triple::mipsel ||
        Triple.getArch() == llvm::Triple::mips64 ||
        Triple.getArch() == llvm::Triple::mips64el) {
+    StringRef CPUName;
+    StringRef ABIName;
+    mips::getMipsCPUAndABI(Args, Triple, CPUName, ABIName);
+    // For n64 ABI, PIC is always true, except in case when -mno-abicalls
+    // option is used. And we exit at next check if that's true,
+    // regardless of PIC being set below.
+    if (ABIName == "n64")
+      PIC = true;
     // When targettng MIPS with -mno-abicalls, it's always static.
     if(Args.hasArg(options::OPT_mno_abicalls))
       return std::make_tuple(llvm::Reloc::Static, 0U, false);
     // Unlike other architectures, MIPS, even with -fPIC/-mxgot/multigot,
     // does not use PIC level 2 for historical reasons.
     IsPICLevelTwo = false;
   }
 

test/Driver/mips-abicalls-error.c

+// RUN: not %clang -c -target mips64-linux-gnu -fPIC -mno-abicalls %s 2>&1 | FileCheck %s
+// CHECK: error: position-independent code requires ‘-mabicalls’

test/Driver/mips-abicalls-warning.c

 // REQUIRES: mips-registered-target
-// RUN: %clang -### -c -target mips64-mti-elf -fno-PIC -mabicalls %s 2>&1 | FileCheck %s
-// CHECK: warning: ignoring '-mabicalls' option as it cannot be used with non position-independent code and the N64 ABI
+// RUN: %clang -### -c -target mips64-mti-elf -fno-pic %s 2>&1 | FileCheck -check-prefix=CHECK-PIC1-IMPLICIT %s
+// CHECK-PIC1-IMPLICIT: warning: ignoring '-fno-pic' option as it cannot be used with implicit use of -mabicalls and the N64 ABI
+
+// RUN: %clang -### -c -target mips64-mti-elf -fno-pic -mabicalls %s 2>&1 | FileCheck -check-prefix=CHECK-PIC1-EXPLICIT %s
+// CHECK-PIC1-EXPLICIT: warning: ignoring '-fno-pic' option as it cannot be used with explicit use of -mabicalls and the N64 ABI
+
+// RUN: %clang -### -c -target mips64-mti-elf -fno-PIC %s 2>&1 | FileCheck -check-prefix=CHECK-PIC2-IMPLICIT %s
+// CHECK-PIC2-IMPLICIT: warning: ignoring '-fno-PIC' option as it cannot be used with implicit use of -mabicalls and the N64 ABI
+
+// RUN: %clang -### -c -target mips64-mti-elf -fno-PIC -mabicalls %s 2>&1 | FileCheck -check-prefix=CHECK-PIC2-EXPLICIT %s
+// CHECK-PIC2-EXPLICIT: warning: ignoring '-fno-PIC' option as it cannot be used with explicit use of -mabicalls and the N64 ABI
 
 // RUN: %clang -### -c -target mips-mti-elf -mlong-calls %s 2>&1 | FileCheck -check-prefix=LONGCALL-IMP %s
 // LONGCALL-IMP: warning: ignoring '-mlong-calls' option as it is not currently supported with the implicit usage of -mabicalls
 
 // RUN: %clang -### -c -target mips-mti-elf -mlong-calls -mabicalls %s 2>&1 | FileCheck -check-prefix=LONGCALL-EXP %s
 // LONGCALL-EXP: warning: ignoring '-mlong-calls' option as it is not currently supported with -mabicalls

test/Driver/mips-as.c

 // MIPS32R2-EB-PIC: "-KPIC"
 //
 // RUN: %clang -target mipsel-linux-gnu -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS32R2-DEF-EL-AS %s
 // MIPS32R2-DEF-EL-AS: as{{(.exe)?}}" "-march" "mips32r2" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EL"
 //
 // RUN: %clang -target mips64-linux-gnu -### \
-// RUN:   -no-integrated-as -fno-pic -c %s 2>&1 \
+// RUN:   -no-integrated-as -fno-pic -mno-abicalls -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-EB-AS %s
 // MIPS64R2-EB-AS: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-EB-AS-PIC %s
 // MIPS64R2-EB-AS-PIC: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64el-linux-gnu -### \
-// RUN:   -no-integrated-as -c -fno-pic %s 2>&1 \
+// RUN:   -no-integrated-as -c -fno-pic -mno-abicalls %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-DEF-EL-AS %s
 // MIPS64R2-DEF-EL-AS: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64"  "-mno-shared" "-EL"
 //
 // RUN: %clang -target mips64el-linux-gnu -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-DEF-EL-AS-PIC %s
 // MIPS64R2-DEF-EL-AS-PIC: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-EL" "-KPIC"
 //

 // MIPS32R2-EL-AS: as{{(.exe)?}}" "-march" "mips32r2" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EL"
 //
 // RUN: %clang -target mips64el-linux-gnu -mabi=64 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-EL-AS-PIC %s
 // MIPS64R2-EL-AS-PIC: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-EL" "-KPIC"
 //
 // RUN: %clang -target mips64el-linux-gnu -mabi=64 -### \
-// RUN:   -no-integrated-as -c %s -fno-pic 2>&1 \
+// RUN:   -no-integrated-as -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS64R2-EL-AS %s
 // MIPS64R2-EL-AS: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-mno-shared" "-EL"
 //
 // RUN: %clang -target mips-linux-gnu -march=mips32r2 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-32R2 %s
 // MIPS-32R2: as{{(.exe)?}}" "-march" "mips32r2" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EB"
 //
 // RUN: %clang -target mips-linux-gnu -march=p5600 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-P5600 %s
 // MIPS-P5600: as{{(.exe)?}}" "-march" "p5600" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -march=octeon -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-OCTEON-PIC %s
 // MIPS-OCTEON-PIC: as{{(.exe)?}}" "-march" "octeon" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -march=octeon -### \
-// RUN:   -no-integrated-as -c %s -fno-pic 2>&1 \
+// RUN:   -no-integrated-as -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-OCTEON %s
 // MIPS-OCTEON: as{{(.exe)?}}" "-march" "octeon" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips-linux-gnu -mips1 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-1 %s
 // MIPS-ALIAS-1: as{{(.exe)?}}" "-march" "mips1" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EB"
 //

 // MIPS-ALIAS-32R6: as{{(.exe)?}}" "-march" "mips32r6" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64-PIC %s
 // MIPS-ALIAS-64-PIC: as{{(.exe)?}}" "-march" "mips64" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64 -### \
-// RUN:   -no-integrated-as -c -fno-pic %s 2>&1 \
+// RUN:   -no-integrated-as -c -fno-pic -mno-abicalls %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64 %s
 // MIPS-ALIAS-64: as{{(.exe)?}}" "-march" "mips64" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r2 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R2-PIC %s
 // MIPS-ALIAS-64R2-PIC: as{{(.exe)?}}" "-march" "mips64r2" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r3 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R3-PIC %s
 // MIPS-ALIAS-64R3-PIC: as{{(.exe)?}}" "-march" "mips64r3" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r3 -### \
-// RUN:   -no-integrated-as -c %s -fno-pic 2>&1 \
+// RUN:   -no-integrated-as -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R3 %s
 // MIPS-ALIAS-64R3: as{{(.exe)?}}" "-march" "mips64r3" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r5 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R5-PIC %s
 // MIPS-ALIAS-64R5-PIC: as{{(.exe)?}}" "-march" "mips64r5" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r5 -### \
-// RUN:   -no-integrated-as -c %s -fno-pic 2>&1 \
+// RUN:   -no-integrated-as -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R5 %s
 // MIPS-ALIAS-64R5: as{{(.exe)?}}" "-march" "mips64r5" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r6 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R6-PIC %s
 // MIPS-ALIAS-64R6-PIC: as{{(.exe)?}}" "-march" "mips64r6" "-mabi" "64" "-EB" "-KPIC"
 //
 // RUN: %clang -target mips64-linux-gnu -mips64r6 -### \
-// RUN:   -no-integrated-as -c %s -fno-pic 2>&1 \
+// RUN:   -no-integrated-as -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-ALIAS-64R6 %s
 // MIPS-ALIAS-64R6: as{{(.exe)?}}" "-march" "mips64r6" "-mabi" "64" "-mno-shared" "-EB"
 //
 // RUN: %clang -target mips-linux-gnu -mno-mips16 -mips16 -### \
 // RUN:   -no-integrated-as -c %s 2>&1 \
 // RUN:   | FileCheck -check-prefix=MIPS-16 %s
 // MIPS-16: as{{(.exe)?}}" "-march" "mips32r2" "-mabi" "32" "-mno-shared" "-call_nonpic" "-EB" "-mips16"
 //

test/Driver/mips-features.c

 // Check handling MIPS specific features options.
 //
 // -mabicalls
 // RUN: %clang -target mips-linux-gnu -### -c %s -mno-abicalls -mabicalls 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MABICALLS %s
 // CHECK-MABICALLS: "-target-feature" "-noabicalls"
 //
 // -mno-abicalls
 // RUN: %clang -target mips-linux-gnu -### -c %s -mabicalls -mno-abicalls 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MNOABICALLS %s
 // CHECK-MNOABICALLS: "-target-feature" "+noabicalls"
 //
 // -mno-abicalls non-PIC N64
-// RUN: %clang -target mips64-linux-gnu -### -c -fno-PIC %s 2>&1 \
+// RUN: %clang -target mips64-linux-gnu -### -c -fno-PIC -mno-abicalls %s 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MNOABICALLS-N64NPIC %s
 // CHECK-MNOABICALLS-N64NPIC: "-target-feature" "+noabicalls"
 //
 // -mgpopt
 // RUN: %clang -target mips-linux-gnu -### -c %s -mno-gpopt -mgpopt -Wno-unsupported-gpopt 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MGPOPT-DEF-ABICALLS %s
 // CHECK-MGPOPT-DEF-ABICALLS-NOT: "-mllvm" "-mgpopt"
 //

 // CHECK-MNOEMBEDDEDDATA: "-mllvm" "-membedded-data=0"
 //
 // -mno-abicalls -mgpopt
 // RUN: %clang -target mips-linux-gnu -### -c %s -mno-abicalls -mgpopt 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-MEMBEDDEDDATADEF %s
 // CHECK-MEMBEDDEDDATADEF-NOT: "-mllvm" "-membedded-data"
 //
 // MIPS64 + N64: -fno-pic -> -mno-abicalls -mgpopt
-// RUN: %clang -target mips64-mti-elf -mabi=64 -### -c %s -fno-pic 2>&1 \
+// RUN: %clang -target mips64-mti-elf -mabi=64 -### -c %s -fno-pic -mno-abicalls 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-N64-GPOPT %s
 // CHECK-N64-GPOPT: "-target-feature" "+noabicalls"
 // CHECK-N64-GPOPT: "-mllvm" "-mgpopt"
 //
 // MIPS64 + N64: -fno-pic -mno-gpopt
-// RUN: %clang -target mips64-mti-elf -mabi=64 -### -c %s -fno-pic -mno-gpopt 2>&1 \
+// RUN: %clang -target mips64-mti-elf -mabi=64 -### -c %s -fno-pic -mno-abicalls -mno-gpopt 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-N64-MNO-GPOPT %s
 // CHECK-N64-MNO-GPOPT: "-target-feature" "+noabicalls"
 // CHECK-N64-MNO-GPOPT-NOT: "-mllvm" "-mgpopt"
 //
 // MIPS64 + N64: -mgpopt (-fpic is implicit)
 // RUN: %clang -target mips64-mti-linux-gnu -mabi=64 -### -c %s -mgpopt 2>&1 \
 // RUN:   | FileCheck --check-prefix=CHECK-N64-PIC-GPOPT %s
 // CHECK-N64-PIC-GPOPT-NOT: "-mllvm" "-mgpopt"