Remove external call from v3 and use pointer value directly

llvm/lib/Target/SBF/SBFISelLowering.cpp

@@ -599,15 +599,10 @@ SDValue SBFTargetLowering::LowerCall(TargetLowering::CallLoweringInfo &CLI,
                                         G->getOffset(), 0);
   } else if (ExternalSymbolSDNode *E = dyn_cast<ExternalSymbolSDNode>(Callee)) {
     Callee = DAG.getTargetExternalSymbol(E->getSymbol(), PtrVT, 0);
-  } else if (ConstantSDNode * CNode = dyn_cast<ConstantSDNode>(Callee)) {
-    uint64_t Cte = CNode->getZExtValue();
-    uint64_t U32Max = static_cast<uint64_t>
-        (std::numeric_limits<uint32_t>::max());
-    if (Subtarget->getHasStaticSyscalls() && Cte >= U32Max - MaxSyscall) {
-      NodeCode = SBFISD::SYSCALL;
-      uint64_t SyscallCode = U32Max - Cte;
-      Callee = DAG.getConstant(SyscallCode, CLI.DL, MVT::i64);
-    }
+  } else if (isa<ConstantSDNode>(Callee) && Subtarget->getHasStaticSyscalls()) {
+    // When static syscalls are enabled and we have a constant operand for call,
+    // we emit a syscall.
+    NodeCode = SBFISD::SYSCALL;
   }
 
   // Returns a chain & a flag for retval copy to use.

llvm/lib/Target/SBF/SBFInstrInfo.td

@@ -963,7 +963,7 @@ def : Pat<(i64 (and (i64 GPR:$src), 0xffffFFFF)),
 // Calls
 def : Pat<(SBFcall tglobaladdr:$dst), (JAL tglobaladdr:$dst)>;
 def : Pat<(SBFcall texternalsym:$dst), (JAL texternalsym:$dst)>;
-def : Pat<(SBFcall imm:$dst), (JAL imm:$dst)>;
+def : Pat<(SBFcall imm:$dst), (JAL imm:$dst)>, Requires<[SBFNoStaticSyscalls]>;
 def : Pat<(SBFcall GPR:$dst), (JALX GPR:$dst)>, Requires<[SBFNoCallxSrc]>;
 def : Pat<(SBFcall GPR:$dst), (JALX_v2 GPR:$dst)>, Requires<[SBFCallxSrc]>;
 def : Pat<(SBFSyscall imm:$imm), (SYSCALL_v3 imm:$imm)>, Requires<[SBFHasStaticSyscalls]>;

llvm/test/CodeGen/SBF/call_internal.ll

@@ -1,8 +1,8 @@
-; RUN: llc < %s -march=sbf --show-mc-encoding | FileCheck --check-prefix=CHECK-ASM %s
-; RUN: llc -march=sbf --filetype=obj -o - %s | llvm-objdump -d - | FileCheck --check-prefix=CHECK-OBJ %s
-; RUN: llc < %s -march=sbf -mcpu=sbfv2 --show-mc-encoding | FileCheck --check-prefix=CHECK-ASM %s
+; RUN: llc < %s -march=sbf --show-mc-encoding | FileCheck --check-prefixes=CHECK-ASM,CHECK-ASM-V0 %s
+; RUN: llc -march=sbf --filetype=obj -o - %s | llvm-objdump -d - | FileCheck --check-prefixes=CHECK-OBJ,CHECK-OBJ-V0 %s
+; RUN: llc < %s -march=sbf -mcpu=sbfv2 --show-mc-encoding | FileCheck --check-prefixes=CHECK-ASM,CHECK-ASM-V3 %s
 ; RUN: llc -march=sbf -mcpu=sbfv2 --filetype=obj -o - %s | llvm-objdump -d -
-;                                       | FileCheck --check-prefix=CHECK-OBJ %s
+;                                       | FileCheck --check-prefixes=CHECK-OBJ,CHECK-OBJ-V3 %s
 
 @.str = private unnamed_addr constant [5 x i8] c"foo\0A\00", align 1
 
@@ -16,8 +16,11 @@ entry:
 ; Function Attrs: nounwind
 define dso_local i64 @entrypoint(ptr noundef %input) local_unnamed_addr #1 {
 entry:
-; CHECK-ASM: call 1811268606      # encoding: [0x85,0x00,0x00,0x00,0xfe,0xc3,0xf5,0x6b]
-; CHECK-OBJ: 85 00 00 00 fe c3 f5 6b	call 0x6bf5c3fe
+; CHECK-ASM-V0: call 1811268606         # encoding: [0x85,0x00,0x00,0x00,0xfe,0xc3,0xf5,0x6b]
+; CHECK-ASM-V3: syscall 1811268606      # encoding: [0x95,0x00,0x00,0x00,0xfe,0xc3,0xf5,0x6b]
+
+; CHECK-OBJ-V0: 85 00 00 00 fe c3 f5 6b	call 0x6bf5c3fe
+; CHECK-OBJ-V3: 95 00 00 00 fe c3 f5 6b	syscall 0x6bf5c3fe
 
   tail call void inttoptr (i64 1811268606 to ptr)(ptr noundef nonnull @.str, i64 noundef 4) #3
   %add.ptr = getelementptr inbounds i8, ptr %input, i64 4

llvm/test/CodeGen/SBF/static_syscall.ll

@@ -1,25 +1,25 @@
-; RUN: llc -march=sbf < %s | FileCheck --check-prefix=CHECK-V1 %s
-; RUN: llc -march=sbf -mattr=+static-syscalls -show-mc-encoding < %s | FileCheck --check-prefix=CHECK-V2 %s
+; RUN: llc -march=sbf < %s | FileCheck --check-prefix=CHECK-V0 %s
+; RUN: llc -march=sbf -mattr=+static-syscalls -show-mc-encoding < %s | FileCheck --check-prefix=CHECK-V3 %s
 
 
 ; Function Attrs: nounwind
 define dso_local i32 @test(i32 noundef %a, i32 noundef %b) {
 entry:
 ; CHECK-LABEL: test
 
-; CHECK-V1: call -2
-; CHECK-V2: syscall 1   # encoding: [0x95,0x00,0x00,0x00,0x01,0x00,0x00,0x00]
-  %syscall_1 = tail call i32 inttoptr (i64 4294967294 to ptr)(i32 noundef %a, i32 noundef %b)
+; CHECK-V0: call 2
+; CHECK-V3 syscall 2   # encoding: [0x95,0x00,0x00,0x00,0x01,0x00,0x00,0x00]
+  %syscall_1 = tail call i32 inttoptr (i64 2 to ptr)(i32 noundef %a, i32 noundef %b)
 
-; CHECK-V1: call -12
-; CHECK-V2: syscall 11  # encoding: [0x95,0x00,0x00,0x00,0x0b,0x00,0x00,0x00]
-  %syscall_2 = tail call i32 inttoptr (i64 4294967284 to ptr)(i32 noundef %a, i32 noundef %b)
+; CHECK-V0: call 11
+; CHECK-V3: syscall 11  # encoding: [0x95,0x00,0x00,0x00,0x0b,0x00,0x00,0x00]
+  %syscall_2 = tail call i32 inttoptr (i64 11 to ptr)(i32 noundef %a, i32 noundef %b)
 
-; CHECK-V1: call -112
-; CHECK-V2: call -112
-  %not_syscall = tail call i32 inttoptr (i64 4294967184 to ptr)(i32 noundef %a, i32 noundef %b)
+; CHECK-V0: call 112
+; CHECK-V3: syscall 112
+  %syscall_3 = tail call i32 inttoptr (i64 112 to ptr)(i32 noundef %a, i32 noundef %b)
 
   %add_1 = add i32 %syscall_1, %syscall_2
-  %add_2 = add i32 %add_1, %not_syscall
+  %add_2 = add i32 %add_1, %syscall_3
   ret i32 %add_1
 }

llvm/test/CodeGen/SBF/static_syscall_2.ll

@@ -0,0 +1,50 @@
+; RUN: llc -march=sbf -mattr=+static-syscalls < %s | FileCheck --check-prefix=CHECK %s
+
+; Syscall declaration in C:
+;
+; int c_declaration(int a, int b) {
+;    int (*const syscall)(int a, int b) = (void*)50;
+;    return syscall(a, b);
+; }
+; The following is the unoptimized output from clang:
+
+define dso_local i32 @c_declaration(i32 noundef %a, i32 noundef %b) #0 {
+entry:
+  %a.addr = alloca i32, align 4
+  %b.addr = alloca i32, align 4
+  %syscall = alloca ptr, align 8
+  store i32 %a, ptr %a.addr, align 4
+  store i32 %b, ptr %b.addr, align 4
+  store ptr inttoptr (i64 50 to ptr), ptr %syscall, align 8
+  %0 = load i32, ptr %a.addr, align 4
+  %1 = load i32, ptr %b.addr, align 4
+
+; Ensure the syscall instruction is emitted
+; CHECK: syscall 50
+
+  %call = call i32 inttoptr (i64 50 to ptr)(i32 noundef %0, i32 noundef %1)
+  ret i32 %call
+}
+
+; Syscall declaration in Rust:
+;
+;  #[no_mangle]
+;  pub unsafe fn rust_declaration(b: u64) -> u32 {
+;      let syscall : extern "C" fn(b: u64) -> u32 = core::mem::transmute(60u64);
+;      return syscall(b);
+;  }
+; The following is the unoptimized output from rustc:
+
+define i32 @rust_declaration(i64 %b) unnamed_addr {
+start:
+  %syscall.dbg.spill = alloca [8 x i8], align 8
+  %b.dbg.spill = alloca [8 x i8], align 8
+  store i64 %b, ptr %b.dbg.spill, align 8
+  store ptr getelementptr (i8, ptr null, i64 60), ptr %syscall.dbg.spill, align 8
+
+; Ensure the syscall instruction is emitted
+; CHECK: syscall 60
+
+  %_0 = call i32 getelementptr (i8, ptr null, i64 60)(i64 %b)
+  ret i32 %_0
+}