[clang] [llvm] [BPF] Add load-acquire and store-release instructions under -mcpu=v5 (PR #108636)

via cfe-commits cfe-commits at lists.llvm.org
Mon Sep 16 13:10:03 PDT 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Peilin Ye (peilin-ye)

<details>
<summary>Changes</summary>

As discussed in [1], introduce BPF instructions with load-acquire and
store-release semantics under -mcpu=v5.

A "load_acquire" is a BPF_LDX instruction with a new mode modifier,
BPF_MEMACQ ("acquiring atomic load").  Similarly, a "store_release" is a
BPF_STX instruction with another new mode modifier, BPF_MEMREL
("releasing atomic store").

BPF_MEMACQ and BPF_MEMREL share the same numeric value, 0x7 (or 0b111).
For example:

  long foo(long *ptr) {
      return __atomic_load_n(ptr, __ATOMIC_ACQUIRE);
  }

foo() can be compiled to:

  f9 10 00 00 00 00 00 00 r0 = load_acquire((u64 *)(r1 + 0x0))
  95 00 00 00 00 00 00 00 exit

Opcode 0xf9, or 0b11111001, can be decoded as:

  0b 111        11     001
     BPF_MEMACQ BPF_DW BPF_LDX

Similarly:

  void bar(short *ptr, short val) {
      __atomic_store_n(ptr, val, __ATOMIC_RELEASE);
  }

bar() can be compiled to:

  eb 21 00 00 00 00 00 00 store_release((u16 *)(r1 + 0x0), w2)
  95 00 00 00 00 00 00 00 exit

Opcode 0xeb, or 0b11101011, can be decoded as:

  0b 111        01    011
     BPF_MEMREL BPF_H BPF_STX

Inline assembly is also supported.  For example:

  asm volatile("%0 = load_acquire((u64 *)(%1 + 0x0))" :
               "=r"(ret) : "r"(ptr) : "memory");

Let 'llvm-objdump -d' use -mcpu=v5 by default, just like commit
https://github.com/llvm/llvm-project/commit/03958680b23dafd961ea0606c77d8e6bc8d80781 ("[BPF] Make llvm-objdump disasm default cpu v4
(https://github.com/llvm/llvm-project/pull/102166)").

Add two macros, __BPF_FEATURE_LOAD_ACQUIRE and
__BPF_FEATURE_STORE_RELEASE, to let developers detect these new features
in source code.  They can also be disabled using two new llc options,
-disable-load-acquire and -disable-store-release, respectively.

Refactored BPFSubtarget::initSubtargetFeatures(), as well as LOAD,
STORE, LOAD32 and STORE32 classes in BPFInstrInfo.td, to make this
easier.

[1] https://lore.kernel.org/all/20240729183246.4110549-1-yepeilin@<!-- -->google.com/

---

Patch is 21.96 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/108636.diff


14 Files Affected:

- (modified) clang/lib/Basic/Targets/BPF.cpp (+7-2) 
- (modified) clang/lib/Basic/Targets/BPF.h (+1-1) 
- (modified) clang/test/Misc/target-invalid-cpu-note/bpf.c (+1) 
- (modified) llvm/lib/Object/ELFObjectFile.cpp (+1-1) 
- (modified) llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp (+2) 
- (modified) llvm/lib/Target/BPF/BPF.td (+1) 
- (modified) llvm/lib/Target/BPF/BPFInstrFormats.td (+2) 
- (modified) llvm/lib/Target/BPF/BPFInstrInfo.td (+69-18) 
- (modified) llvm/lib/Target/BPF/BPFMISimplifyPatchable.cpp (+8-4) 
- (modified) llvm/lib/Target/BPF/BPFSubtarget.cpp (+21-12) 
- (modified) llvm/lib/Target/BPF/BPFSubtarget.h (+5) 
- (modified) llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp (+5-2) 
- (added) llvm/test/CodeGen/BPF/acquire-release.ll (+95) 
- (added) llvm/test/CodeGen/BPF/assembler-disassembler-v5.s (+22) 


``````````diff
diff --git a/clang/lib/Basic/Targets/BPF.cpp b/clang/lib/Basic/Targets/BPF.cpp
index a94ceee5a6a5e7..7a381e4853093a 100644
--- a/clang/lib/Basic/Targets/BPF.cpp
+++ b/clang/lib/Basic/Targets/BPF.cpp
@@ -67,10 +67,15 @@ void BPFTargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__BPF_FEATURE_GOTOL");
     Builder.defineMacro("__BPF_FEATURE_ST");
   }
+
+  if (CpuVerNum >= 5) {
+    Builder.defineMacro("__BPF_FEATURE_LOAD_ACQUIRE");
+    Builder.defineMacro("__BPF_FEATURE_STORE_RELEASE");
+  }
 }
 
-static constexpr llvm::StringLiteral ValidCPUNames[] = {"generic", "v1", "v2",
-                                                        "v3", "v4", "probe"};
+static constexpr llvm::StringLiteral ValidCPUNames[] = {
+    "generic", "v1", "v2", "v3", "v4", "v5", "probe"};
 
 bool BPFTargetInfo::isValidCPUName(StringRef Name) const {
   return llvm::is_contained(ValidCPUNames, Name);
diff --git a/clang/lib/Basic/Targets/BPF.h b/clang/lib/Basic/Targets/BPF.h
index d19b37dd4df7a7..3ca9c07f955f9b 100644
--- a/clang/lib/Basic/Targets/BPF.h
+++ b/clang/lib/Basic/Targets/BPF.h
@@ -106,7 +106,7 @@ class LLVM_LIBRARY_VISIBILITY BPFTargetInfo : public TargetInfo {
   void fillValidCPUList(SmallVectorImpl<StringRef> &Values) const override;
 
   bool setCPU(const std::string &Name) override {
-    if (Name == "v3" || Name == "v4") {
+    if (Name == "v3" || Name == "v4" || Name == "v5") {
       HasAlu32 = true;
     }
 
diff --git a/clang/test/Misc/target-invalid-cpu-note/bpf.c b/clang/test/Misc/target-invalid-cpu-note/bpf.c
index fe925f86cdd137..7f90e64ab16f16 100644
--- a/clang/test/Misc/target-invalid-cpu-note/bpf.c
+++ b/clang/test/Misc/target-invalid-cpu-note/bpf.c
@@ -10,6 +10,7 @@
 // CHECK-SAME: {{^}}, v2
 // CHECK-SAME: {{^}}, v3
 // CHECK-SAME: {{^}}, v4
+// CHECK-SAME: {{^}}, v5
 // CHECK-SAME: {{^}}, probe
 // CHECK-SAME: {{$}}
 
diff --git a/llvm/lib/Object/ELFObjectFile.cpp b/llvm/lib/Object/ELFObjectFile.cpp
index f79c233d93fe8e..408af398e4ef17 100644
--- a/llvm/lib/Object/ELFObjectFile.cpp
+++ b/llvm/lib/Object/ELFObjectFile.cpp
@@ -442,7 +442,7 @@ std::optional<StringRef> ELFObjectFileBase::tryGetCPUName() const {
   case ELF::EM_PPC64:
     return StringRef("future");
   case ELF::EM_BPF:
-    return StringRef("v4");
+    return StringRef("v5");
   default:
     return std::nullopt;
   }
diff --git a/llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp b/llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
index 9672ed009e9be1..4721097b765a08 100644
--- a/llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
+++ b/llvm/lib/Target/BPF/AsmParser/BPFAsmParser.cpp
@@ -237,6 +237,7 @@ struct BPFOperand : public MCParsedAsmOperand {
         .Case("exit", true)
         .Case("lock", true)
         .Case("ld_pseudo", true)
+        .Case("store_release", true)
         .Default(false);
   }
 
@@ -273,6 +274,7 @@ struct BPFOperand : public MCParsedAsmOperand {
         .Case("cmpxchg_64", true)
         .Case("cmpxchg32_32", true)
         .Case("addr_space_cast", true)
+        .Case("load_acquire", true)
         .Default(false);
   }
 };
diff --git a/llvm/lib/Target/BPF/BPF.td b/llvm/lib/Target/BPF/BPF.td
index dff76ca07af511..dd2d4989561bc3 100644
--- a/llvm/lib/Target/BPF/BPF.td
+++ b/llvm/lib/Target/BPF/BPF.td
@@ -32,6 +32,7 @@ def : Proc<"v1", []>;
 def : Proc<"v2", []>;
 def : Proc<"v3", [ALU32]>;
 def : Proc<"v4", [ALU32]>;
+def : Proc<"v5", [ALU32]>;
 def : Proc<"probe", []>;
 
 def BPFInstPrinter : AsmWriter {
diff --git a/llvm/lib/Target/BPF/BPFInstrFormats.td b/llvm/lib/Target/BPF/BPFInstrFormats.td
index feffdbc69465ea..cb68b0d1250e6e 100644
--- a/llvm/lib/Target/BPF/BPFInstrFormats.td
+++ b/llvm/lib/Target/BPF/BPFInstrFormats.td
@@ -94,6 +94,8 @@ def BPF_IND  : BPFModeModifer<0x2>;
 def BPF_MEM  : BPFModeModifer<0x3>;
 def BPF_MEMSX  : BPFModeModifer<0x4>;
 def BPF_ATOMIC : BPFModeModifer<0x6>;
+def BPF_MEMACQ : BPFModeModifer<0x7>;
+def BPF_MEMREL : BPFModeModifer<0x7>;
 
 class BPFAtomicFlag<bits<4> val> {
   bits<4> Value = val;
diff --git a/llvm/lib/Target/BPF/BPFInstrInfo.td b/llvm/lib/Target/BPF/BPFInstrInfo.td
index f7e17901c7ed5e..79de3e77b2b123 100644
--- a/llvm/lib/Target/BPF/BPFInstrInfo.td
+++ b/llvm/lib/Target/BPF/BPFInstrInfo.td
@@ -60,6 +60,8 @@ def BPFHasSdivSmod : Predicate<"Subtarget->hasSdivSmod()">;
 def BPFNoMovsx : Predicate<"!Subtarget->hasMovsx()">;
 def BPFNoBswap : Predicate<"!Subtarget->hasBswap()">;
 def BPFHasStoreImm : Predicate<"Subtarget->hasStoreImm()">;
+def BPFHasLoadAcquire : Predicate<"Subtarget->hasLoadAcquire()">;
+def BPFHasStoreRelease : Predicate<"Subtarget->hasStoreRelease()">;
 
 class ImmediateAsmOperand<string name> : AsmOperandClass {
   let Name = name;
@@ -497,12 +499,11 @@ def LD_pseudo
 }
 
 // STORE instructions
-class STORE<BPFWidthModifer SizeOp, string OpcodeStr, list<dag> Pattern>
-    : TYPE_LD_ST<BPF_MEM.Value, SizeOp.Value,
+class STORE<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string AsmString, list<dag> Pattern>
+    : TYPE_LD_ST<ModOp.Value, SizeOp.Value,
                  (outs),
                  (ins GPR:$src, MEMri:$addr),
-                 "*("#OpcodeStr#" *)($addr) = $src",
-                 Pattern> {
+                 AsmString, Pattern> {
   bits<4> src;
   bits<20> addr;
 
@@ -513,7 +514,11 @@ class STORE<BPFWidthModifer SizeOp, string OpcodeStr, list<dag> Pattern>
 }
 
 class STOREi64<BPFWidthModifer Opc, string OpcodeStr, PatFrag OpNode>
-    : STORE<Opc, OpcodeStr, [(OpNode GPR:$src, ADDRri:$addr)]>;
+    : STORE<Opc, BPF_MEM, "*("#OpcodeStr#" *)($addr) = $src", [(OpNode GPR:$src, ADDRri:$addr)]>;
+
+class STORE_RELEASEi64<BPFWidthModifer Opc, string OpcodeStr, PatFrag OpNode>
+    : STORE<Opc, BPF_MEMREL, "store_release(("#OpcodeStr#" *)($addr), $src)",
+            [(OpNode GPR:$src, ADDRri:$addr)]>;
 
 let Predicates = [BPFNoALU32] in {
   def STW : STOREi64<BPF_W, "u32", truncstorei32>;
@@ -522,6 +527,16 @@ let Predicates = [BPFNoALU32] in {
 }
 def STD : STOREi64<BPF_DW, "u64", store>;
 
+class releasing_store<PatFrag base>
+  : PatFrag<(ops node:$val, node:$ptr), (base node:$val, node:$ptr)> {
+  let IsAtomic = 1;
+  let IsAtomicOrderingRelease = 1;
+}
+
+let Predicates = [BPFHasStoreRelease] in {
+  def STDREL : STORE_RELEASEi64<BPF_DW, "u64", releasing_store<atomic_store_64>>;
+}
+
 class STORE_imm<BPFWidthModifer SizeOp,
                 string OpcodeStr, dag Pattern>
     : TYPE_LD_ST<BPF_MEM.Value, SizeOp.Value,
@@ -567,12 +582,11 @@ let Predicates = [BPFHasALU32, BPFHasStoreImm] in {
 }
 
 // LOAD instructions
-class LOAD<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, list<dag> Pattern>
+class LOAD<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string AsmString, list<dag> Pattern>
     : TYPE_LD_ST<ModOp.Value, SizeOp.Value,
                  (outs GPR:$dst),
                  (ins MEMri:$addr),
-                 "$dst = *("#OpcodeStr#" *)($addr)",
-                 Pattern> {
+                 AsmString, Pattern> {
   bits<4> dst;
   bits<20> addr;
 
@@ -583,7 +597,13 @@ class LOAD<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, list<
 }
 
 class LOADi64<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, PatFrag OpNode>
-    : LOAD<SizeOp, ModOp, OpcodeStr, [(set i64:$dst, (OpNode ADDRri:$addr))]>;
+    : LOAD<SizeOp, ModOp, "$dst = *("#OpcodeStr#" *)($addr)",
+           [(set i64:$dst, (OpNode ADDRri:$addr))]>;
+
+class LOAD_ACQUIREi64<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr,
+                      PatFrag OpNode>
+    : LOAD<SizeOp, ModOp, "$dst = load_acquire(("#OpcodeStr#" *)($addr))",
+           [(set i64:$dst, (OpNode ADDRri:$addr))]>;
 
 let isCodeGenOnly = 1 in {
   class CORE_LD<RegisterClass RegClass, string Sz>
@@ -622,6 +642,16 @@ let Predicates = [BPFHasLdsx] in {
 
 def LDD : LOADi64<BPF_DW, BPF_MEM, "u64", load>;
 
+class acquiring_load<PatFrags base>
+    : PatFrag<(ops node:$ptr), (base node:$ptr)> {
+  let IsAtomic = 1;
+  let IsAtomicOrderingAcquire = 1;
+}
+
+let Predicates = [BPFHasLoadAcquire] in {
+  def LDDACQ : LOAD_ACQUIREi64<BPF_DW, BPF_MEMACQ, "u64", acquiring_load<atomic_load_64>>;
+}
+
 class BRANCH<BPFJumpOp Opc, string OpcodeStr, list<dag> Pattern>
     : TYPE_ALU_JMP<Opc.Value, BPF_K.Value,
                    (outs),
@@ -1069,12 +1099,11 @@ def : Pat<(i32 (trunc GPR:$src)),
 def : Pat<(i64 (anyext GPR32:$src)),
           (INSERT_SUBREG (i64 (IMPLICIT_DEF)), GPR32:$src, sub_32)>;
 
-class STORE32<BPFWidthModifer SizeOp, string OpcodeStr, list<dag> Pattern>
-    : TYPE_LD_ST<BPF_MEM.Value, SizeOp.Value,
+class STORE32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string AsmString, list<dag> Pattern>
+    : TYPE_LD_ST<ModOp.Value, SizeOp.Value,
                  (outs),
                  (ins GPR32:$src, MEMri:$addr),
-                 "*("#OpcodeStr#" *)($addr) = $src",
-                 Pattern> {
+                 AsmString, Pattern> {
   bits<4> src;
   bits<20> addr;
 
@@ -1085,20 +1114,30 @@ class STORE32<BPFWidthModifer SizeOp, string OpcodeStr, list<dag> Pattern>
 }
 
 class STOREi32<BPFWidthModifer Opc, string OpcodeStr, PatFrag OpNode>
-    : STORE32<Opc, OpcodeStr, [(OpNode GPR32:$src, ADDRri:$addr)]>;
+    : STORE32<Opc, BPF_MEM, "*("#OpcodeStr#" *)($addr) = $src",
+              [(OpNode GPR32:$src, ADDRri:$addr)]>;
+
+class STORE_RELEASEi32<BPFWidthModifer Opc, string OpcodeStr, PatFrag OpNode>
+    : STORE32<Opc, BPF_MEMREL, "store_release(("#OpcodeStr#" *)($addr), $src)",
+              [(OpNode GPR32:$src, ADDRri:$addr)]>;
 
 let Predicates = [BPFHasALU32], DecoderNamespace = "BPFALU32" in {
   def STW32 : STOREi32<BPF_W, "u32", store>;
   def STH32 : STOREi32<BPF_H, "u16", truncstorei16>;
   def STB32 : STOREi32<BPF_B, "u8", truncstorei8>;
+
+  let Predicates = [BPFHasStoreRelease] in {
+    def STWREL32 : STORE_RELEASEi32<BPF_W, "u32", releasing_store<atomic_store_32>>;
+    def STHREL32 : STORE_RELEASEi32<BPF_H, "u16", releasing_store<atomic_store_16>>;
+    def STBREL32 : STORE_RELEASEi32<BPF_B, "u8", releasing_store<atomic_store_8>>;
+  }
 }
 
-class LOAD32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, list<dag> Pattern>
+class LOAD32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string AsmString, list<dag> Pattern>
     : TYPE_LD_ST<ModOp.Value, SizeOp.Value,
                 (outs GPR32:$dst),
                 (ins MEMri:$addr),
-                "$dst = *("#OpcodeStr#" *)($addr)",
-                Pattern> {
+                AsmString, Pattern> {
   bits<4> dst;
   bits<20> addr;
 
@@ -1109,12 +1148,24 @@ class LOAD32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, lis
 }
 
 class LOADi32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr, PatFrag OpNode>
-    : LOAD32<SizeOp, ModOp, OpcodeStr, [(set i32:$dst, (OpNode ADDRri:$addr))]>;
+    : LOAD32<SizeOp, ModOp, "$dst = *("#OpcodeStr#" *)($addr)",
+             [(set i32:$dst, (OpNode ADDRri:$addr))]>;
+
+class LOAD_ACQUIREi32<BPFWidthModifer SizeOp, BPFModeModifer ModOp, string OpcodeStr,
+                      PatFrag OpNode>
+    : LOAD32<SizeOp, ModOp, "$dst = load_acquire(("#OpcodeStr#" *)($addr))",
+             [(set i32:$dst, (OpNode ADDRri:$addr))]>;
 
 let Predicates = [BPFHasALU32], DecoderNamespace = "BPFALU32" in {
   def LDW32 : LOADi32<BPF_W, BPF_MEM, "u32", load>;
   def LDH32 : LOADi32<BPF_H, BPF_MEM, "u16", zextloadi16>;
   def LDB32 : LOADi32<BPF_B, BPF_MEM, "u8", zextloadi8>;
+
+  let Predicates = [BPFHasLoadAcquire] in {
+    def LDWACQ32 : LOAD_ACQUIREi32<BPF_W, BPF_MEMACQ, "u32", acquiring_load<atomic_load_32>>;
+    def LDHACQ32 : LOAD_ACQUIREi32<BPF_H, BPF_MEMACQ, "u16", acquiring_load<atomic_load_az_16>>;
+    def LDBACQ32 : LOAD_ACQUIREi32<BPF_B, BPF_MEMACQ, "u8", acquiring_load<atomic_load_az_8>>;
+  }
 }
 
 let Predicates = [BPFHasALU32] in {
diff --git a/llvm/lib/Target/BPF/BPFMISimplifyPatchable.cpp b/llvm/lib/Target/BPF/BPFMISimplifyPatchable.cpp
index 39390e8c38f8c1..0763550cb03419 100644
--- a/llvm/lib/Target/BPF/BPFMISimplifyPatchable.cpp
+++ b/llvm/lib/Target/BPF/BPFMISimplifyPatchable.cpp
@@ -100,21 +100,25 @@ static bool isST(unsigned Opcode) {
 }
 
 static bool isSTX32(unsigned Opcode) {
-  return Opcode == BPF::STB32 || Opcode == BPF::STH32 || Opcode == BPF::STW32;
+  return Opcode == BPF::STB32 || Opcode == BPF::STH32 || Opcode == BPF::STW32 ||
+         Opcode == BPF::STBREL32 || Opcode == BPF::STHREL32 ||
+         Opcode == BPF::STWREL32;
 }
 
 static bool isSTX64(unsigned Opcode) {
   return Opcode == BPF::STB || Opcode == BPF::STH || Opcode == BPF::STW ||
-         Opcode == BPF::STD;
+         Opcode == BPF::STD || Opcode == BPF::STDREL;
 }
 
 static bool isLDX32(unsigned Opcode) {
-  return Opcode == BPF::LDB32 || Opcode == BPF::LDH32 || Opcode == BPF::LDW32;
+  return Opcode == BPF::LDB32 || Opcode == BPF::LDH32 || Opcode == BPF::LDW32 ||
+         Opcode == BPF::LDBACQ32 || Opcode == BPF::LDHACQ32 ||
+         Opcode == BPF::LDWACQ32;
 }
 
 static bool isLDX64(unsigned Opcode) {
   return Opcode == BPF::LDB || Opcode == BPF::LDH || Opcode == BPF::LDW ||
-         Opcode == BPF::LDD;
+         Opcode == BPF::LDD || Opcode == BPF::LDDACQ;
 }
 
 static bool isLDSX(unsigned Opcode) {
diff --git a/llvm/lib/Target/BPF/BPFSubtarget.cpp b/llvm/lib/Target/BPF/BPFSubtarget.cpp
index 305e9a2bf2cda3..a52c39efccedcb 100644
--- a/llvm/lib/Target/BPF/BPFSubtarget.cpp
+++ b/llvm/lib/Target/BPF/BPFSubtarget.cpp
@@ -40,6 +40,12 @@ static cl::opt<bool> Disable_gotol("disable-gotol", cl::Hidden, cl::init(false),
 static cl::opt<bool>
     Disable_StoreImm("disable-storeimm", cl::Hidden, cl::init(false),
                      cl::desc("Disable BPF_ST (immediate store) insn"));
+static cl::opt<bool>
+    Disable_load_acquire("disable-load-acquire", cl::Hidden, cl::init(false),
+                         cl::desc("Disable load-acquire insns"));
+static cl::opt<bool>
+    Disable_store_release("disable-store-release", cl::Hidden, cl::init(false),
+                          cl::desc("Disable store-release insns"));
 
 void BPFSubtarget::anchor() {}
 
@@ -62,6 +68,8 @@ void BPFSubtarget::initializeEnvironment() {
   HasSdivSmod = false;
   HasGotol = false;
   HasStoreImm = false;
+  HasLoadAcquire = false;
+  HasStoreRelease = false;
 }
 
 void BPFSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
@@ -69,29 +77,30 @@ void BPFSubtarget::initSubtargetFeatures(StringRef CPU, StringRef FS) {
     CPU = "v3";
   if (CPU == "probe")
     CPU = sys::detail::getHostCPUNameForBPF();
-  if (CPU == "generic" || CPU == "v1")
-    return;
-  if (CPU == "v2") {
-    HasJmpExt = true;
+  if (CPU.empty() || CPU == "generic" || CPU == "v1")
     return;
-  }
-  if (CPU == "v3") {
+
+  int CpuVerNum = CPU.back() - '0';
+  if (CpuVerNum >= 2)
     HasJmpExt = true;
+
+  if (CpuVerNum >= 3) {
     HasJmp32 = true;
     HasAlu32 = true;
-    return;
   }
-  if (CPU == "v4") {
-    HasJmpExt = true;
-    HasJmp32 = true;
-    HasAlu32 = true;
+
+  if (CpuVerNum >= 4) {
     HasLdsx = !Disable_ldsx;
     HasMovsx = !Disable_movsx;
     HasBswap = !Disable_bswap;
     HasSdivSmod = !Disable_sdiv_smod;
     HasGotol = !Disable_gotol;
     HasStoreImm = !Disable_StoreImm;
-    return;
+  }
+
+  if (CpuVerNum >= 5) {
+    HasLoadAcquire = !Disable_load_acquire;
+    HasStoreRelease = !Disable_store_release;
   }
 }
 
diff --git a/llvm/lib/Target/BPF/BPFSubtarget.h b/llvm/lib/Target/BPF/BPFSubtarget.h
index 33747546eadc3b..aa7995c3af5ecf 100644
--- a/llvm/lib/Target/BPF/BPFSubtarget.h
+++ b/llvm/lib/Target/BPF/BPFSubtarget.h
@@ -66,6 +66,9 @@ class BPFSubtarget : public BPFGenSubtargetInfo {
   // whether cpu v4 insns are enabled.
   bool HasLdsx, HasMovsx, HasBswap, HasSdivSmod, HasGotol, HasStoreImm;
 
+  // whether cpu v5 insns are enabled.
+  bool HasLoadAcquire, HasStoreRelease;
+
   std::unique_ptr<CallLowering> CallLoweringInfo;
   std::unique_ptr<InstructionSelector> InstSelector;
   std::unique_ptr<LegalizerInfo> Legalizer;
@@ -92,6 +95,8 @@ class BPFSubtarget : public BPFGenSubtargetInfo {
   bool hasSdivSmod() const { return HasSdivSmod; }
   bool hasGotol() const { return HasGotol; }
   bool hasStoreImm() const { return HasStoreImm; }
+  bool hasLoadAcquire() const { return HasLoadAcquire; }
+  bool hasStoreRelease() const { return HasStoreRelease; }
 
   bool isLittleEndian() const { return IsLittleEndian; }
 
diff --git a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
index 536bee5393843a..d1b9769d3bed96 100644
--- a/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
+++ b/llvm/lib/Target/BPF/Disassembler/BPFDisassembler.cpp
@@ -58,7 +58,9 @@ class BPFDisassembler : public MCDisassembler {
     BPF_IND = 0x2,
     BPF_MEM = 0x3,
     BPF_MEMSX = 0x4,
-    BPF_ATOMIC = 0x6
+    BPF_ATOMIC = 0x6,
+    BPF_MEMACQ = 0x7,
+    BPF_MEMREL = 0x7
   };
 
   BPFDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
@@ -177,7 +179,8 @@ DecodeStatus BPFDisassembler::getInstruction(MCInst &Instr, uint64_t &Size,
   uint8_t InstMode = getInstMode(Insn);
   if ((InstClass == BPF_LDX || InstClass == BPF_STX) &&
       getInstSize(Insn) != BPF_DW &&
-      (InstMode == BPF_MEM || InstMode == BPF_ATOMIC) &&
+      (InstMode == BPF_MEM || InstMode == BPF_ATOMIC ||
+       InstMode == BPF_MEMACQ /* or BPF_MEMREL */) &&
       STI.hasFeature(BPF::ALU32))
     Result = decodeInstruction(DecoderTableBPFALU3264, Instr, Insn, Address,
                                this, STI);
diff --git a/llvm/test/CodeGen/BPF/acquire-release.ll b/llvm/test/CodeGen/BPF/acquire-release.ll
new file mode 100644
index 00000000000000..1c7db417b6c43f
--- /dev/null
+++ b/llvm/test/CodeGen/BPF/acquire-release.ll
@@ -0,0 +1,95 @@
+; RUN: llc < %s -march=bpfel -mcpu=v5 -verify-machineinstrs -show-mc-encoding | FileCheck %s
+;
+; Source:
+;   char load_acquire_i8(char *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   short load_acquire_i16(short *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   int load_acquire_i32(int *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   long load_acquire_i64(long *p) {
+;     return __atomic_load_n(p, __ATOMIC_ACQUIRE);
+;   }
+;   void store_release_i8(char *p, char v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i16(short *p, short v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i32(int *p, int v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+;   void store_release_i64(long *p, long v) {
+;     __atomic_store_n(p, v, __ATOMIC_RELEASE);
+;   }
+
+; CHECK-LABEL: load_acquire_i8
+; CHECK: w0 = load_acquire((u8 *)(r1 + 0)) # encoding: [0xf1,0x10,0x00,0x00,0x00,0x00,0x00,0x00]
+define dso_local i8 @load_acquire_i8(ptr nocapture noundef readonly %p) local_unnamed_addr {
+entry:
+  %0 = load atomic i8, ptr %p acquire, align 1
+  ret i8 %0
+}
+
+; CHECK-LABEL: load_acquire_i16
+; CHECK: w0 = load_acquire((u16 *)(r1 + 0)) # encoding: [0xe9,0x10,0x00,0x00,0x00,0x00,0x00,0x00]
+define dso_local i16 @load_acquire_i16(ptr nocapture noundef readonly %p) local_unnamed_addr {
+entry:
+  %0 = load atomic i16, ptr %p acquire, align 2
+  ret i16 %0
+}
+
+; CHECK-LABEL: load_acquire_i32
+; CHECK: w0 = load_acquire((u32 *)(r1 + 0)) # encoding: [0xe1,0x10,0x00,0x00,0x00,0x00,0x00,0x00]
+define dso_local i32 @load_acquire_i32(ptr nocapture noundef readonly %p) local_unnamed_addr {
+entry:
+  %0 = load atomic i32, ptr %p acquire, align 4
+  ret i32 %0
+}
+
+; CHECK-LABEL: load_acquire_i64
+; CHECK: r0 = load_acquire((u64 *)(r1 + 0)) # encoding: [0xf9,0x10,0x00,0x00,0x00,0x00,0x00,0x00]
+define dso_local i64 @load_acquire_i64(ptr nocapture noundef readonly %p) local_unnamed_addr {
+entry:
+  %0 = load atomic i64, ptr %p acquire, align 8
+  ret i64 %0
+}
+
+; CHECK-LABEL: store_release_i8
+; CHECK: store_release((u8 *)(r1 + 0), w2) # encoding: [0xf3,0x21,0x00,0x00,0x00,0x00,0x00,0x00]
+define void @store_release_i8(ptr nocapture noundef writeonly %p,
+                              i8 noundef signext %v) local_unnamed_addr {
+entry:
+  store atomic i8 %v, ptr %p release, align 1
+  ret void
+}
+
+; CHECK-LABEL: store_release_i16
+; CHECK: store_release((u16 *)(r1 + 0), w2) # encoding: [0xeb,0x21,0x00,0x00,0x00,0x00,0x00,0x00]
+define void @store_release_i16(ptr nocapture noundef writeonly %p,
+                               i16 noundef signext %v) local_unnamed_addr ...
[truncated]

``````````

</details>


https://github.com/llvm/llvm-project/pull/108636


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