[SPARC] Support reserving arbitrary general purpose registers #74927

koachan · 2023-12-09T11:33:07Z

This adds support for marking arbitrary general purpose registers - except for those with special purpose (G0, I6-I7, O6-O7) - as reserved, as needed by some software like the Linux kernel.

llvmbot · 2023-12-09T11:33:36Z

@llvm/pr-subscribers-clang

@llvm/pr-subscribers-clang-driver

Author: Koakuma (koachan)

Changes

This adds support for marking arbitrary general purpose registers - except for those with special purpose (G0, I6-I7, O6-O7) - as reserved, as needed by some software like the Linux kernel.

Patch is 24.86 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/74927.diff

12 Files Affected:

(modified) clang/include/clang/Driver/Options.td (+12)
(modified) clang/lib/Driver/ToolChains/Arch/Sparc.cpp (+81)
(added) clang/test/Driver/sparc-fixed-register.c (+181)
(modified) llvm/lib/Target/Sparc/Sparc.td (+14)
(modified) llvm/lib/Target/Sparc/SparcISelLowering.cpp (+23)
(modified) llvm/lib/Target/Sparc/SparcRegisterInfo.cpp (+44-1)
(modified) llvm/lib/Target/Sparc/SparcRegisterInfo.h (+3)
(modified) llvm/lib/Target/Sparc/SparcRegisterInfo.td (+4)
(modified) llvm/lib/Target/Sparc/SparcSubtarget.cpp (+5-1)
(modified) llvm/lib/Target/Sparc/SparcSubtarget.h (+11)
(added) llvm/test/CodeGen/SPARC/reserved-arg-regs.ll (+25)
(modified) llvm/test/CodeGen/SPARC/reserved-regs.ll (+17)

diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
index df12ba8fbcb29..94bdeff28d014 100644
--- a/clang/include/clang/Driver/Options.td
+++ b/clang/include/clang/Driver/Options.td
@@ -5730,6 +5730,18 @@ def mvis3 : Flag<["-"], "mvis3">, Group<m_sparc_Features_Group>;
 def mno_vis3 : Flag<["-"], "mno-vis3">, Group<m_sparc_Features_Group>;
 def mhard_quad_float : Flag<["-"], "mhard-quad-float">, Group<m_sparc_Features_Group>;
 def msoft_quad_float : Flag<["-"], "msoft-quad-float">, Group<m_sparc_Features_Group>;
+foreach i = {1-7} in
+  def ffixed_g#i : Flag<["-"], "ffixed-g"#i>, Group<m_sparc_Features_Group>,
+    HelpText<"Reserve the G"#i#" register (SPARC only)">;
+foreach i = {0-5} in
+  def ffixed_o#i : Flag<["-"], "ffixed-o"#i>, Group<m_sparc_Features_Group>,
+    HelpText<"Reserve the O"#i#" register (SPARC only)">;
+foreach i = {0-7} in
+  def ffixed_l#i : Flag<["-"], "ffixed-l"#i>, Group<m_sparc_Features_Group>,
+    HelpText<"Reserve the L"#i#" register (SPARC only)">;
+foreach i = {0-5} in
+  def ffixed_i#i : Flag<["-"], "ffixed-i"#i>, Group<m_sparc_Features_Group>,
+    HelpText<"Reserve the I"#i#" register (SPARC only)">;
 } // let Flags = [TargetSpecific]
 
 // M68k features flags
diff --git a/clang/lib/Driver/ToolChains/Arch/Sparc.cpp b/clang/lib/Driver/ToolChains/Arch/Sparc.cpp
index 22e583021515e..ae1a4ba788262 100644
--- a/clang/lib/Driver/ToolChains/Arch/Sparc.cpp
+++ b/clang/lib/Driver/ToolChains/Arch/Sparc.cpp
@@ -178,4 +178,85 @@ void sparc::getSparcTargetFeatures(const Driver &D, const ArgList &Args,
     else
       Features.push_back("-hard-quad-float");
   }
+
+  if (Args.hasArg(options::OPT_ffixed_g1))
+    Features.push_back("+reserve-g1");
+
+  if (Args.hasArg(options::OPT_ffixed_g2))
+    Features.push_back("+reserve-g2");
+
+  if (Args.hasArg(options::OPT_ffixed_g3))
+    Features.push_back("+reserve-g3");
+
+  if (Args.hasArg(options::OPT_ffixed_g4))
+    Features.push_back("+reserve-g4");
+
+  if (Args.hasArg(options::OPT_ffixed_g5))
+    Features.push_back("+reserve-g5");
+
+  if (Args.hasArg(options::OPT_ffixed_g6))
+    Features.push_back("+reserve-g6");
+
+  if (Args.hasArg(options::OPT_ffixed_g7))
+    Features.push_back("+reserve-g7");
+
+  if (Args.hasArg(options::OPT_ffixed_o0))
+    Features.push_back("+reserve-o0");
+
+  if (Args.hasArg(options::OPT_ffixed_o1))
+    Features.push_back("+reserve-o1");
+
+  if (Args.hasArg(options::OPT_ffixed_o2))
+    Features.push_back("+reserve-o2");
+
+  if (Args.hasArg(options::OPT_ffixed_o3))
+    Features.push_back("+reserve-o3");
+
+  if (Args.hasArg(options::OPT_ffixed_o4))
+    Features.push_back("+reserve-o4");
+
+  if (Args.hasArg(options::OPT_ffixed_o5))
+    Features.push_back("+reserve-o5");
+
+  if (Args.hasArg(options::OPT_ffixed_l0))
+    Features.push_back("+reserve-l0");
+
+  if (Args.hasArg(options::OPT_ffixed_l1))
+    Features.push_back("+reserve-l1");
+
+  if (Args.hasArg(options::OPT_ffixed_l2))
+    Features.push_back("+reserve-l2");
+
+  if (Args.hasArg(options::OPT_ffixed_l3))
+    Features.push_back("+reserve-l3");
+
+  if (Args.hasArg(options::OPT_ffixed_l4))
+    Features.push_back("+reserve-l4");
+
+  if (Args.hasArg(options::OPT_ffixed_l5))
+    Features.push_back("+reserve-l5");
+
+  if (Args.hasArg(options::OPT_ffixed_l6))
+    Features.push_back("+reserve-l6");
+
+  if (Args.hasArg(options::OPT_ffixed_l7))
+    Features.push_back("+reserve-l7");
+
+  if (Args.hasArg(options::OPT_ffixed_i0))
+    Features.push_back("+reserve-i0");
+
+  if (Args.hasArg(options::OPT_ffixed_i1))
+    Features.push_back("+reserve-i1");
+
+  if (Args.hasArg(options::OPT_ffixed_i2))
+    Features.push_back("+reserve-i2");
+
+  if (Args.hasArg(options::OPT_ffixed_i3))
+    Features.push_back("+reserve-i3");
+
+  if (Args.hasArg(options::OPT_ffixed_i4))
+    Features.push_back("+reserve-i4");
+
+  if (Args.hasArg(options::OPT_ffixed_i5))
+    Features.push_back("+reserve-i5");
 }
diff --git a/clang/test/Driver/sparc-fixed-register.c b/clang/test/Driver/sparc-fixed-register.c
new file mode 100644
index 0000000000000..24880b9c9d86f
--- /dev/null
+++ b/clang/test/Driver/sparc-fixed-register.c
@@ -0,0 +1,181 @@
+// RUN: %clang --target=sparc-none-gnu -ffixed-g1 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G1 < %t %s
+// CHECK-FIXED-G1: "-target-feature" "+reserve-g1"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g2 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G2 < %t %s
+// CHECK-FIXED-G2: "-target-feature" "+reserve-g2"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g3 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G3 < %t %s
+// CHECK-FIXED-G3: "-target-feature" "+reserve-g3"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g4 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G4 < %t %s
+// CHECK-FIXED-G4: "-target-feature" "+reserve-g4"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g5 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G5 < %t %s
+// CHECK-FIXED-G5: "-target-feature" "+reserve-g5"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g6 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G6 < %t %s
+// CHECK-FIXED-G6: "-target-feature" "+reserve-g6"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-g7 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-G7 < %t %s
+// CHECK-FIXED-G7: "-target-feature" "+reserve-g7"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o0 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O0 < %t %s
+// CHECK-FIXED-O0: "-target-feature" "+reserve-o0"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o1 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O1 < %t %s
+// CHECK-FIXED-O1: "-target-feature" "+reserve-o1"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o2 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O2 < %t %s
+// CHECK-FIXED-O2: "-target-feature" "+reserve-o2"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o3 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O3 < %t %s
+// CHECK-FIXED-O3: "-target-feature" "+reserve-o3"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o4 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O4 < %t %s
+// CHECK-FIXED-O4: "-target-feature" "+reserve-o4"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-o5 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-O5 < %t %s
+// CHECK-FIXED-O5: "-target-feature" "+reserve-o5"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l0 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L0 < %t %s
+// CHECK-FIXED-L0: "-target-feature" "+reserve-l0"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l1 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L1 < %t %s
+// CHECK-FIXED-L1: "-target-feature" "+reserve-l1"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l2 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L2 < %t %s
+// CHECK-FIXED-L2: "-target-feature" "+reserve-l2"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l3 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L3 < %t %s
+// CHECK-FIXED-L3: "-target-feature" "+reserve-l3"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l4 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L4 < %t %s
+// CHECK-FIXED-L4: "-target-feature" "+reserve-l4"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l5 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L5 < %t %s
+// CHECK-FIXED-L5: "-target-feature" "+reserve-l5"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l6 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L6 < %t %s
+// CHECK-FIXED-L6: "-target-feature" "+reserve-l6"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-l7 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-L7 < %t %s
+// CHECK-FIXED-L7: "-target-feature" "+reserve-l7"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i0 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I0 < %t %s
+// CHECK-FIXED-I0: "-target-feature" "+reserve-i0"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i1 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I1 < %t %s
+// CHECK-FIXED-I1: "-target-feature" "+reserve-i1"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i2 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I2 < %t %s
+// CHECK-FIXED-I2: "-target-feature" "+reserve-i2"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i3 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I3 < %t %s
+// CHECK-FIXED-I3: "-target-feature" "+reserve-i3"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i4 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I4 < %t %s
+// CHECK-FIXED-I4: "-target-feature" "+reserve-i4"
+
+// RUN: %clang --target=sparc-none-gnu -ffixed-i5 -### %s 2> %t
+// RUN: FileCheck --check-prefix=CHECK-FIXED-I5 < %t %s
+// CHECK-FIXED-I5: "-target-feature" "+reserve-i5"
+
+// Test multiple of reserve-* options together.
+// RUN: %clang --target=sparc-none-gnu \
+// RUN: -ffixed-g1 \
+// RUN: -ffixed-o2 \
+// RUN: -ffixed-l3 \
+// RUN: -ffixed-i4 \
+// RUN: -### %s 2> %t
+// RUN: FileCheck \
+// RUN: --check-prefix=CHECK-FIXED-G1 \
+// RUN: --check-prefix=CHECK-FIXED-O2 \
+// RUN: --check-prefix=CHECK-FIXED-L3 \
+// RUN: --check-prefix=CHECK-FIXED-I4 \
+// RUN: < %t %s
+
+// Test all reserve-* options together.
+// RUN: %clang --target=sparc-none-gnu \
+// RUN: -ffixed-g1 \
+// RUN: -ffixed-g2 \
+// RUN: -ffixed-g3 \
+// RUN: -ffixed-g4 \
+// RUN: -ffixed-g5 \
+// RUN: -ffixed-g6 \
+// RUN: -ffixed-g7 \
+// RUN: -ffixed-o0 \
+// RUN: -ffixed-o1 \
+// RUN: -ffixed-o2 \
+// RUN: -ffixed-o3 \
+// RUN: -ffixed-o4 \
+// RUN: -ffixed-o5 \
+// RUN: -ffixed-l0 \
+// RUN: -ffixed-l1 \
+// RUN: -ffixed-l2 \
+// RUN: -ffixed-l3 \
+// RUN: -ffixed-l4 \
+// RUN: -ffixed-l5 \
+// RUN: -ffixed-l6 \
+// RUN: -ffixed-l7 \
+// RUN: -ffixed-i0 \
+// RUN: -ffixed-i1 \
+// RUN: -ffixed-i2 \
+// RUN: -ffixed-i3 \
+// RUN: -ffixed-i4 \
+// RUN: -ffixed-i5 \
+// RUN: -### %s 2> %t
+// RUN: FileCheck \
+// RUN: --check-prefix=CHECK-FIXED-G1 \
+// RUN: --check-prefix=CHECK-FIXED-G2 \
+// RUN: --check-prefix=CHECK-FIXED-G3 \
+// RUN: --check-prefix=CHECK-FIXED-G4 \
+// RUN: --check-prefix=CHECK-FIXED-G5 \
+// RUN: --check-prefix=CHECK-FIXED-G6 \
+// RUN: --check-prefix=CHECK-FIXED-G7 \
+// RUN: --check-prefix=CHECK-FIXED-O0 \
+// RUN: --check-prefix=CHECK-FIXED-O1 \
+// RUN: --check-prefix=CHECK-FIXED-O2 \
+// RUN: --check-prefix=CHECK-FIXED-O3 \
+// RUN: --check-prefix=CHECK-FIXED-O4 \
+// RUN: --check-prefix=CHECK-FIXED-O5 \
+// RUN: --check-prefix=CHECK-FIXED-L0 \
+// RUN: --check-prefix=CHECK-FIXED-L1 \
+// RUN: --check-prefix=CHECK-FIXED-L2 \
+// RUN: --check-prefix=CHECK-FIXED-L3 \
+// RUN: --check-prefix=CHECK-FIXED-L4 \
+// RUN: --check-prefix=CHECK-FIXED-L5 \
+// RUN: --check-prefix=CHECK-FIXED-L6 \
+// RUN: --check-prefix=CHECK-FIXED-L7 \
+// RUN: --check-prefix=CHECK-FIXED-I0 \
+// RUN: --check-prefix=CHECK-FIXED-I1 \
+// RUN: --check-prefix=CHECK-FIXED-I2 \
+// RUN: --check-prefix=CHECK-FIXED-I3 \
+// RUN: --check-prefix=CHECK-FIXED-I4 \
+// RUN: --check-prefix=CHECK-FIXED-I5 \
+// RUN: < %t %s
diff --git a/llvm/lib/Target/Sparc/Sparc.td b/llvm/lib/Target/Sparc/Sparc.td
index 1a71cfed3128f..29d07bd087e5a 100644
--- a/llvm/lib/Target/Sparc/Sparc.td
+++ b/llvm/lib/Target/Sparc/Sparc.td
@@ -65,6 +65,20 @@ def FeatureSoftFloat : SubtargetFeature<"soft-float", "UseSoftFloat", "true",
 //==== Features added predmoninantly for LEON subtarget support
 include "LeonFeatures.td"
 
+//==== Register allocation tweaks needed by some low-level software
+foreach i = {1-7} in
+    def FeatureReserveG#i : SubtargetFeature<"reserve-g"#i, "ReserveGRegister["#i#"]", "true",
+                                             "Reserve G"#i#", making it unavailable as a GPR">;
+foreach i = {0-5} in
+    def FeatureReserveO#i : SubtargetFeature<"reserve-o"#i, "ReserveORegister["#i#"]", "true",
+                                             "Reserve O"#i#", making it unavailable as a GPR">;
+foreach i = {0-7} in
+    def FeatureReserveL#i : SubtargetFeature<"reserve-l"#i, "ReserveLRegister["#i#"]", "true",
+                                             "Reserve L"#i#", making it unavailable as a GPR">;
+foreach i = {0-5} in
+    def FeatureReserveI#i : SubtargetFeature<"reserve-i"#i, "ReserveIRegister["#i#"]", "true",
+                                             "Reserve I"#i#", making it unavailable as a GPR">;
+
 //===----------------------------------------------------------------------===//
 // Register File, Calling Conv, Instruction Descriptions
 //===----------------------------------------------------------------------===//
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index 4f08014792110..5a7830a1ecf61 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -805,6 +805,7 @@ SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
   bool &isTailCall                      = CLI.IsTailCall;
   CallingConv::ID CallConv              = CLI.CallConv;
   bool isVarArg                         = CLI.IsVarArg;
+  MachineFunction &MF = DAG.getMachineFunction();
 
   // Analyze operands of the call, assigning locations to each operand.
   SmallVector<CCValAssign, 16> ArgLocs;
@@ -1055,6 +1056,10 @@ SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
       ((hasReturnsTwice)
            ? TRI->getRTCallPreservedMask(CallConv)
            : TRI->getCallPreservedMask(DAG.getMachineFunction(), CallConv));
+
+  if (TRI->isAnyArgRegReserved(MF))
+    TRI->emitReservedArgRegCallError(MF);
+
   assert(Mask && "Missing call preserved mask for calling convention");
   Ops.push_back(DAG.getRegisterMask(Mask));
 
@@ -1125,6 +1130,19 @@ Register SparcTargetLowering::getRegisterByName(const char* RegName, LLT VT,
     .Case("g4", SP::G4).Case("g5", SP::G5).Case("g6", SP::G6).Case("g7", SP::G7)
     .Default(0);
 
+  const SparcRegisterInfo *MRI = Subtarget->getRegisterInfo();
+  unsigned DwarfRegNum = MRI->getDwarfRegNum(Reg, false);
+  if (!MRI->isReservedReg(MF, Reg)) {
+    bool IsG = DwarfRegNum < 8, IsO = DwarfRegNum >= 8 && DwarfRegNum < 16,
+         IsL = DwarfRegNum >= 16 && DwarfRegNum < 24, IsI = DwarfRegNum >= 24;
+    unsigned NumInBank = DwarfRegNum % 8;
+    if ((IsG && !Subtarget->isGRegisterReserved(NumInBank)) ||
+        (IsO && !Subtarget->isORegisterReserved(NumInBank)) ||
+        (IsL && !Subtarget->isLRegisterReserved(NumInBank)) ||
+        (IsI && !Subtarget->isIRegisterReserved(NumInBank)))
+      Reg = 0;
+  }
+
   if (Reg)
     return Reg;
 
@@ -1189,6 +1207,7 @@ SparcTargetLowering::LowerCall_64(TargetLowering::CallLoweringInfo &CLI,
   SDLoc DL = CLI.DL;
   SDValue Chain = CLI.Chain;
   auto PtrVT = getPointerTy(DAG.getDataLayout());
+  MachineFunction &MF = DAG.getMachineFunction();
 
   // Analyze operands of the call, assigning locations to each operand.
   SmallVector<CCValAssign, 16> ArgLocs;
@@ -1372,6 +1391,10 @@ SparcTargetLowering::LowerCall_64(TargetLowering::CallLoweringInfo &CLI,
       ((hasReturnsTwice) ? TRI->getRTCallPreservedMask(CLI.CallConv)
                          : TRI->getCallPreservedMask(DAG.getMachineFunction(),
                                                      CLI.CallConv));
+
+  if (TRI->isAnyArgRegReserved(MF))
+    TRI->emitReservedArgRegCallError(MF);
+
   assert(Mask && "Missing call preserved mask for calling convention");
   Ops.push_back(DAG.getRegisterMask(Mask));
 
diff --git a/llvm/lib/Target/Sparc/SparcRegisterInfo.cpp b/llvm/lib/Target/Sparc/SparcRegisterInfo.cpp
index f97bf57627d1a..233f1dfd3ecf2 100644
--- a/llvm/lib/Target/Sparc/SparcRegisterInfo.cpp
+++ b/llvm/lib/Target/Sparc/SparcRegisterInfo.cpp
@@ -12,7 +12,6 @@
 
 #include "SparcRegisterInfo.h"
 #include "Sparc.h"
-#include "SparcMachineFunctionInfo.h"
 #include "SparcSubtarget.h"
 #include "llvm/ADT/BitVector.h"
 #include "llvm/ADT/STLExtras.h"
@@ -20,6 +19,7 @@
 #include "llvm/CodeGen/MachineFunction.h"
 #include "llvm/CodeGen/MachineInstrBuilder.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
+#include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -98,9 +98,52 @@ BitVector SparcRegisterInfo::getReservedRegs(const MachineFunction &MF) const {
   for (unsigned n = 0; n < 31; n++)
     Reserved.set(SP::ASR1 + n);
 
+  for (size_t i = 0; i < SP::IntRegsRegClass.getNumRegs() / 4; ++i) {
+    // Mark both single register and register pairs.
+    if (MF.getSubtarget<SparcSubtarget>().isGRegisterReserved(i)) {
+      Reserved.set(SP::G0 + i);
+      Reserved.set(SP::G0_G1 + i / 2);
+    }
+    if (MF.getSubtarget<SparcSubtarget>().isORegisterReserved(i)) {
+      Reserved.set(SP::O0 + i);
+      Reserved.set(SP::O0_O1 + i / 2);
+    }
+    if (MF.getSubtarget<SparcSubtarget>().isLRegisterReserved(i)) {
+      Reserved.set(SP::L0 + i);
+      Reserved.set(SP::L0_L1 + i / 2);
+    }
+    if (MF.getSubtarget<SparcSubtarget>().isIRegisterReserved(i)) {
+      Reserved.set(SP::I0 + i);
+      Reserved.set(SP::I0_I1 + i / 2);
+    }
+  }
+
   return Reserved;
 }
 
+bool SparcRegisterInfo::isReservedReg(const MachineFunction &MF,
+                                      MCRegister Reg) const {
+  return getReservedRegs(MF)[Reg];
+}
+
+bool SparcRegisterInfo::isAnyArgRegReserved(const MachineFunction &MF) const {
+  bool Outgoing =
+      llvm::any_of(*SP::GPROutgoingArgRegClass.MC,
+                   [this, &MF](MCPhysReg r) { return isReservedReg(MF, r); });
+  bool Incoming =
+      llvm::any_of(*SP::GPRIncomingArgRegClass.MC,
+                   [this, &MF](MCPhysReg r) { return isReservedReg(MF, r); });
+  return Outgoing || Incoming;
+}
+
+void SparcRegisterInfo::emitReservedArgRegCallError(
+    const MachineFunction &MF) const {
+  const Function &F = MF.getFunction();
+  F.getContext().diagnose(DiagnosticInfoUnsupported{
+      F, ("SPARC doesn't support"
+          " function calls if any of the argument registers is reserved.")});
+}
+
 const TargetRegisterClass*
 SparcRegisterInfo::getPointerRegClass(const MachineFunction &MF,
                                       unsigned Kind) const {
diff --git a/llvm/lib/Target/Sparc/SparcRegisterInfo.h b/llvm/lib/Target/Sparc/SparcRegisterInfo.h
index 5b3c1a7ad07dd..67c5d0c0fdac3 100644
--- a/llvm/lib/Target/Sparc/SparcRegisterInfo.h
+++ b/llvm/lib/Target/Sparc/SparcRegisterInfo.h
@@ -30,6 +30,9 @@ struct SparcRegisterInfo : public SparcGenRegisterInfo {
   const uint32_t* getRTCallPreservedMask(CallingConv::ID CC) const;
 
   BitVector getReservedRegs(const MachineFunction &MF) const override;
+  bool isReservedReg(const MachineFunction &MF, MCRegister Reg) const;
+  bool isAnyArgRegReserved(const MachineFunction &MF) const;
+  void emitReservedArgRegCallError(const MachineFunction &MF) const;
 
   const TargetRegisterClass *getPointerRegClass(const MachineFunction &MF,
                                                 unsigned Kind) const override;
diff --git a/llvm/lib/Target/Sparc/SparcRegisterInfo.td b/llvm/lib/Target/Sparc/SparcRegisterInfo.td
index d5ba7464695c5..d8319a8d41dda 100644
--- a/llvm/lib/Target/Sparc/SparcRegisterInfo.td
+++ b/llvm/lib/Target/Sparc/SparcRegisterInfo.td
@@ -370,6 +370,10 @@ def LowQFPRegs : RegisterClass<"SP", [f128], 128, (sequence "Q%u", 0, 7)>;
 // Floating point control register classes.
 def FCCRegs : RegisterClass<"SP", [i1], 1, (sequence "FCC%u", 0, 3)>;
 
+// GPR argument registers.
+def GPROutgoingArg : RegisterClass<"SP", [i32, i64], 32, (sequence "O%u", 0, 5)>;
+def GPRIncomingArg : RegisterClass<"SP", [i32, i64], 32, (sequence "I%u", 0, 5)>;
+
 let isAllocatable = 0 in {
   // Ancillary state registers
   // FIXME: TICK is special-cased here as it can be accessed
diff --git a/llvm/lib/Target/Sparc/SparcSubtarget.cpp b/llvm/lib/Target/Sparc/SparcSubtarget.cpp
index 81c2137ea730f..c7c37af83e206 100644
--- a/llvm/lib/Target/Sparc/SparcSubtarget.cpp
+++ b/llvm/lib/Target/Sparc/SparcSubtarget.cpp
@@ -45,7 +45,11 @@ SparcSubtarget &SparcSubtarget::initializeSubtargetDependencies(StringRef CPU,
 SparcSubtarget::SparcSubtarget(const Triple &TT, const std::string &CPU,
                                const std::string &FS, const TargetMachine &TM,
                                bool is64Bi...
[truncated]

jrtc27 · 2023-12-09T22:59:49Z

Doesn’t the ABI require you to emit magic STT_REGISTER or whatever they are symbols to mark this?

koachan · 2023-12-10T02:03:19Z

Doesn’t the ABI require you to emit magic STT_REGISTER or whatever they are symbols to mark this?

Yeah, when targeting 64-bit and we're not reserving %g2, %g3, %g6, or %g7 then we should emit STT_SPARC_REGISTER entries for those registers.
However, currently we never emit any of those in the first place. This should be fixed but I think it is better done as a separate PR?

koachan · 2023-12-19T02:20:26Z

Ping?

llvm/lib/Target/Sparc/SparcISelLowering.cpp

clang/include/clang/Driver/Options.td

llvm/lib/Target/Sparc/SparcISelLowering.cpp

llvm/lib/Target/Sparc/SparcRegisterInfo.cpp

llvm/lib/Target/Sparc/SparcISelLowering.cpp

llvm/lib/Target/Sparc/SparcRegisterInfo.cpp

llvm/lib/Target/Sparc/SparcSubtarget.h

brad0 · 2024-01-17T04:28:13Z

There is a conflict at the moment. Also 18 is coming up.

This adds support for marking arbitrary general purpose registers - except for those with special purpose (G0, I6-I7, O6-O7) - as reserved, as needed by some software like the Linux kernel.

koachan · 2024-02-04T04:11:51Z

Ping?

llvm/lib/Target/Sparc/SparcSubtarget.h

brad0 · 2024-02-07T20:58:35Z

@koachan ?

brad0 · 2024-02-11T05:46:54Z

@s-barannikov How does that look?

s-barannikov · 2024-02-11T07:02:29Z

Still LGTM

…4927) This adds support for marking arbitrary general purpose registers - except for those with special purpose (G0, I6-I7, O6-O7) - as reserved, as needed by some software like the Linux kernel. (cherry picked from commit c2f9885)

koachan requested review from jrtc27, brad0, rorth and s-barannikov December 9, 2023 11:33

llvmbot added clang Clang issues not falling into any other category backend:Sparc clang:driver 'clang' and 'clang++' user-facing binaries. Not 'clang-cl' labels Dec 9, 2023

s-barannikov reviewed Dec 19, 2023

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koachan requested a review from s-barannikov December 21, 2023 14:58

s-barannikov reviewed Dec 21, 2023

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llvm/lib/Target/Sparc/SparcISelLowering.cpp Show resolved Hide resolved

s-barannikov reviewed Dec 21, 2023

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llvm/lib/Target/Sparc/SparcRegisterInfo.cpp Outdated Show resolved Hide resolved

s-barannikov reviewed Jan 13, 2024

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koachan added 5 commits January 21, 2024 16:05

[SPARC] Support reserving arbitrary general purpose registers

fd0bae4

This adds support for marking arbitrary general purpose registers - except for those with special purpose (G0, I6-I7, O6-O7) - as reserved, as needed by some software like the Linux kernel.

fixup! [SPARC] Support reserving arbitrary general purpose registers

a11f306

fixup! [SPARC] Support reserving arbitrary general purpose registers

ee9b15e

fixup! [SPARC] Support reserving arbitrary general purpose registers

eb8204d

fixup! [SPARC] Support reserving arbitrary general purpose registers

a7e35ea

koachan force-pushed the sparc64-regalloc-flags branch from 0d14b2d to a7e35ea Compare January 22, 2024 01:08

brad0 requested a review from s-barannikov January 25, 2024 07:20

s-barannikov approved these changes Feb 6, 2024

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llvm/lib/Target/Sparc/SparcSubtarget.h Outdated Show resolved Hide resolved

koachan added 2 commits February 10, 2024 08:54

fixup! [SPARC] Support reserving arbitrary general purpose registers

30a4823

fixup! [SPARC] Support reserving arbitrary general purpose registers

90140f2

brad0 merged commit c2f9885 into llvm:main Feb 11, 2024
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brad0 mentioned this pull request Feb 11, 2024

Merge c2f9885a8aa3a820eefdacccf3fcc6b9d87e3284 into 18.x #81396

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pointhex mentioned this pull request May 7, 2024

getStyleDiagHandler #91314

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aemerson mentioned this pull request May 9, 2024

release/18.x: [AArc64][GlobalISel] Fix legalizer assert for G_INSERT_VECTOR_ELT - manual merge #91672

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[SPARC] Support reserving arbitrary general purpose registers #74927

[SPARC] Support reserving arbitrary general purpose registers #74927

koachan commented Dec 9, 2023

llvmbot commented Dec 9, 2023 •

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s-barannikov commented Feb 11, 2024

[SPARC] Support reserving arbitrary general purpose registers #74927

[SPARC] Support reserving arbitrary general purpose registers #74927

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