[clang] [llvm] [RISCV] Add support for RISC-V Pointer Masking (PR #79929)

Michael Maitland via cfe-commits cfe-commits at lists.llvm.org
Mon Feb 5 08:00:18 PST 2024


https://github.com/michaelmaitland updated https://github.com/llvm/llvm-project/pull/79929

>From fafae54117daf3d871e9df63cc4f1430a433edf0 Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Mon, 29 Jan 2024 12:33:59 -0800
Subject: [PATCH 1/3] [RISCV] Add support for RISC-V Pointer Masking

This patch implements the v0.8.1 specification. This includes support of
the `Ssnpm`, `Smnpm`, `Smmpm`, `Sspm` and `Supm` extensions that make up
RISC-V pointer masking.

All of these extensions only require emitting attribute containing
correct `march` string. `Ssnpm`, `Smnpm`, `Smmpm` extensions introduce a
2-bit WARL field (PMM). The extension does not specify how PMM is set,
and therefore this patch does not need to address this. One example of
how it *could* be set is using the Zicsr instructions to update the PMM
bits of the described registers.

The full specification can be found at
https://github.com/riscv/riscv-j-extension/blob/master/zjpm-spec.pdf
---
 .../test/Preprocessor/riscv-target-features.c | 45 +++++++++++++++++++
 llvm/docs/RISCVUsage.rst                      |  3 ++
 llvm/docs/ReleaseNotes.rst                    |  2 +
 llvm/lib/Support/RISCVISAInfo.cpp             |  6 +++
 llvm/lib/Target/RISCV/RISCVFeatures.td        | 34 ++++++++++++++
 llvm/test/CodeGen/RISCV/attributes.ll         | 20 +++++++++
 llvm/unittests/Support/RISCVISAInfoTest.cpp   |  5 +++
 7 files changed, 115 insertions(+)

diff --git a/clang/test/Preprocessor/riscv-target-features.c b/clang/test/Preprocessor/riscv-target-features.c
index f81ec7ac4532f2..add96c0046cc73 100644
--- a/clang/test/Preprocessor/riscv-target-features.c
+++ b/clang/test/Preprocessor/riscv-target-features.c
@@ -159,6 +159,11 @@
 
 // Experimental extensions
 
+// CHECK-NOT: __riscv_smmpm{{.*$}}
+// CHECK-NOT: __riscv_smnpm{{.*$}}
+// CHECK-NOT: __riscv_ssnpm{{.*$}}
+// CHECK-NOT: __riscv_sspm{{.*$}}
+// CHECK-NOT: __riscv_supm{{.*$}}
 // CHECK-NOT: __riscv_zaamo {{.*$}}
 // CHECK-NOT: __riscv_zacas {{.*$}}
 // CHECK-NOT: __riscv_zalasr {{.*$}}
@@ -1567,6 +1572,46 @@
 // RUN:   -o - | FileCheck --check-prefix=CHECK-ZICFISS-EXT %s
 // CHECK-ZICFISS-EXT: __riscv_zicfiss 4000{{$}}
 
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_ssnpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SSNPM-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_ssnpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SSNPM-EXT %s
+// CHECK-SSNPM-EXT: __riscv_ssnpm 8000{{$}}
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_smnpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SMNPM-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_smnpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SMNPM-EXT %s
+// CHECK-SMNPM-EXT: __riscv_smnpm 8000{{$}}
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_smmpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SMMPM-EXT %s
+// RUN: %clang --target=riscv64 -menable-experimental-extensions \
+// RUN:   -march=rv64i_smmpm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SMMPM-EXT %s
+// CHECK-SMMPM-EXT: __riscv_smmpm 8000{{$}}
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_sspm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SSPM-EXT %s
+// RUN: %clang --target=riscv64 \
+// RUN:   -march=rv64i_sspm0p8 -E -dM %s -menable-experimental-extensions \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SSPM-EXT %s
+// CHECK-SSPM-EXT: __riscv_sspm 8000{{$}}
+
+// RUN: %clang --target=riscv32 -menable-experimental-extensions \
+// RUN:   -march=rv32i_supm0p8 -E -dM %s \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SUPM-EXT %s
+// RUN: %clang --target=riscv64 \
+// RUN:   -march=rv64i_supm0p8 -E -dM %s -menable-experimental-extensions \
+// RUN:   -o - | FileCheck --check-prefix=CHECK-SUPM-EXT %s
+// CHECK-SUPM-EXT: __riscv_supm 8000{{$}}
+
 // Misaligned
 
 // RUN: %clang --target=riscv32-unknown-linux-gnu -march=rv32i -E -dM %s \
diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index e6d1f41849302e..ae043315aaae20 100644
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -243,6 +243,9 @@ LLVM supports (to various degrees) a number of experimental extensions.  All exp
 
 The primary goal of experimental support is to assist in the process of ratification by providing an existence proof of an implementation, and simplifying efforts to validate the value of a proposed extension against large code bases.  Experimental extensions are expected to either transition to ratified status, or be eventually removed.  The decision on whether to accept an experimental extension is currently done on an entirely case by case basis; if you want to propose one, attending the bi-weekly RISC-V sync-up call is strongly advised.
 
+``experimental-ssnpm``, ``experimental-smnpm``, ``experimental-smmpm``, ``experimental-sspm``, ``experimental-supm``
+  LLVM implements the `v0.8.1 draft specification <https://github.com/riscv/riscv-j-extension/blob/master/zjpm-spec.pdf>
+
 ``experimental-zabha``
   LLVM implements assembler support for the `v1.0-rc1 draft specification <https://github.com/riscv/riscv-zabha/tree/v1.0-rc1>`_.
 
diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index 89b999fcbfe9dd..474a321bb1d028 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -101,6 +101,8 @@ Changes to the RISC-V Backend
 * The names of the majority of the S-prefixed (supervisor-level) extension
   names in the RISC-V profiles specification are now recognised.
 * Codegen support was added for the Zimop (May-Be-Operations) extension.
+* Support for the Zicond extension is no longer experimental.
+* The experimental Ssnpm, Smnpm, Smmpm, Sspm, and Supm 0.8.1 Pointer Masking extensions are supported.
 
 Changes to the WebAssembly Backend
 ----------------------------------
diff --git a/llvm/lib/Support/RISCVISAInfo.cpp b/llvm/lib/Support/RISCVISAInfo.cpp
index b4fa20d202d3ea..6fe8eb62e28040 100644
--- a/llvm/lib/Support/RISCVISAInfo.cpp
+++ b/llvm/lib/Support/RISCVISAInfo.cpp
@@ -211,6 +211,12 @@ static const RISCVSupportedExtension SupportedExtensions[] = {
 // NOTE: This table should be sorted alphabetically by extension name.
 // clang-format off
 static const RISCVSupportedExtension SupportedExperimentalExtensions[] = {
+    {"smmpm", {0, 8}},
+    {"smnpm", {0, 8}},
+    {"ssnpm", {0, 8}},
+    {"sspm", {0, 8}},
+    {"supm", {0, 8}},
+
     {"zaamo", {0, 2}},
     {"zabha", {1, 0}},
     {"zacas", {1, 0}},
diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
index af7519cedca114..97359a987e1676 100644
--- a/llvm/lib/Target/RISCV/RISCVFeatures.td
+++ b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -876,6 +876,40 @@ def FeatureStdExtSvpbmt
     : SubtargetFeature<"svpbmt", "HasStdExtSvpbmt", "true",
                        "'Svpbmt' (Page-Based Memory Types)">;
 
+// Pointer Masking extensions
+
+// A supervisor-level extension that provides pointer masking for the next lower
+// privilege mode (U-mode), and for VS- and VU-modes if the H extension is
+// present.
+def FeatureStdExtSsnpm
+    : SubtargetFeature<"experimental-ssnpm", "HasStdExtSsnpm", "true",
+                       "'Ssnpm' (Supervisor-level Pointer Masking)">;
+
+// A machine-level extension that provides pointer masking for the next lower
+// privilege mode (S/HS if S-mode is implemented, or U-mode otherwise).
+def FeatureStdExtSmnpm
+    : SubtargetFeature<"experimental-smnpm", "HasStdExtSmnpm", "true",
+                       "'Smnpm' (Machine-level Pointer Masking)">;
+
+// A machine-level extension that provides pointer masking for M-mode.
+def FeatureStdExtSmmpm
+    : SubtargetFeature<"experimental-smmpm", "HasStdExtSmmpm", "true",
+                       "'Smmpm' (Machine-level Pointer Masking for M-mode)">;
+
+// An extension that indicates that there is pointer-masking support available
+// in supervisor mode, with some facility provided in the supervisor execution
+// environment to control pointer masking.
+def FeatureStdExtSspm
+    : SubtargetFeature<"experimental-sspm", "HasStdExtSspm", "true",
+                       "'Sspm' (Indicates Supervisor-mode Pointer Masking)">;
+
+// An extension that indicates that there is pointer-masking support available
+// in user mode, with some facility provided in the application execution
+// environment to control pointer masking.
+def FeatureStdExtSupm
+    : SubtargetFeature<"experimental-supm", "HasStdExtSupm", "true",
+                       "'Supm' (Indicates User-mode Pointer Masking)">;
+
 //===----------------------------------------------------------------------===//
 // Vendor extensions
 //===----------------------------------------------------------------------===//
diff --git a/llvm/test/CodeGen/RISCV/attributes.ll b/llvm/test/CodeGen/RISCV/attributes.ll
index 89b2190310f77c..088cc0b90a05ac 100644
--- a/llvm/test/CodeGen/RISCV/attributes.ll
+++ b/llvm/test/CodeGen/RISCV/attributes.ll
@@ -116,6 +116,11 @@
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zalrsc %s -o - | FileCheck --check-prefix=RV32ZALRSC %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV32ZICFILP %s
 ; RUN: llc -mtriple=riscv32 -mattr=+experimental-zabha %s -o - | FileCheck --check-prefix=RV32ZABHA %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-ssnpm  %s -o - | FileCheck --check-prefix=RV32SSNPM %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-smnpm  %s -o - | FileCheck --check-prefix=RV32SMNPM %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-smmpm %s -o - | FileCheck --check-prefix=RV32SMMPM %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-sspm %s -o - | FileCheck --check-prefix=RV32SSPM %s
+; RUN: llc -mtriple=riscv32 -mattr=+experimental-supm %s -o - | FileCheck --check-prefix=RV32SUPM %s
 
 ; RUN: llc -mtriple=riscv64 %s -o - | FileCheck %s
 ; RUN: llc -mtriple=riscv64 -mattr=+m %s -o - | FileCheck --check-prefixes=CHECK,RV64M %s
@@ -239,6 +244,11 @@
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zalrsc %s -o - | FileCheck --check-prefix=RV64ZALRSC %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zicfilp %s -o - | FileCheck --check-prefix=RV64ZICFILP %s
 ; RUN: llc -mtriple=riscv64 -mattr=+experimental-zabha %s -o - | FileCheck --check-prefix=RV64ZABHA %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-ssnpm  %s -o - | FileCheck --check-prefix=RV64SSNPM %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-smnpm  %s -o - | FileCheck --check-prefix=RV64SMNPM %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-smmpm %s -o - | FileCheck --check-prefix=RV64SMMPM %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-sspm %s -o - | FileCheck --check-prefix=RV64SSPM %s
+; RUN: llc -mtriple=riscv64 -mattr=+experimental-supm %s -o - | FileCheck --check-prefix=RV64SUPM %s
 
 ; CHECK: .attribute 4, 16
 
@@ -357,6 +367,11 @@
 ; RV32ZALRSC: .attribute 5, "rv32i2p1_zalrsc0p2"
 ; RV32ZICFILP: .attribute 5, "rv32i2p1_zicfilp0p4"
 ; RV32ZABHA: .attribute 5, "rv32i2p1_a2p1_zabha1p0"
+; RV32SSNPM: .attribute 5, "rv32i2p1_ssnpm0p8"
+; RV32SMNPM: .attribute 5, "rv32i2p1_smnpm0p8"
+; RV32SMMPM: .attribute 5, "rv32i2p1_smmpm0p8"
+; RV32SSPM: .attribute 5, "rv32i2p1_sspm0p8"
+; RV32SUPM: .attribute 5, "rv32i2p1_supm0p8"
 
 ; RV64M: .attribute 5, "rv64i2p1_m2p0"
 ; RV64ZMMUL: .attribute 5, "rv64i2p1_zmmul1p0"
@@ -479,6 +494,11 @@
 ; RV64ZALRSC: .attribute 5, "rv64i2p1_zalrsc0p2"
 ; RV64ZICFILP: .attribute 5, "rv64i2p1_zicfilp0p4"
 ; RV64ZABHA: .attribute 5, "rv64i2p1_a2p1_zabha1p0"
+; RV64SSNPM: .attribute 5, "rv64i2p1_ssnpm0p8"
+; RV64SMNPM: .attribute 5, "rv64i2p1_smnpm0p8"
+; RV64SMMPM: .attribute 5, "rv64i2p1_smmpm0p8"
+; RV64SSPM: .attribute 5, "rv64i2p1_sspm0p8"
+; RV64SUPM: .attribute 5, "rv64i2p1_supm0p8"
 
 define i32 @addi(i32 %a) {
   %1 = add i32 %a, 1
diff --git a/llvm/unittests/Support/RISCVISAInfoTest.cpp b/llvm/unittests/Support/RISCVISAInfoTest.cpp
index 8f44c7ba693643..ac6066ebdfb94e 100644
--- a/llvm/unittests/Support/RISCVISAInfoTest.cpp
+++ b/llvm/unittests/Support/RISCVISAInfoTest.cpp
@@ -881,6 +881,11 @@ Experimental extensions
     ztso                0.1
     zvfbfmin            1.0
     zvfbfwma            1.0
+    smmpm               0.8
+    smnpm               0.8
+    ssnpm               0.8
+    sspm                0.8
+    supm                0.8
 
 Use -march to specify the target's extension.
 For example, clang -march=rv32i_v1p0)";

>From 1c11d42c4dce504df4cec27f0e2019b260eb4881 Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Mon, 29 Jan 2024 17:47:51 -0800
Subject: [PATCH 2/3] fixup! add backtick in docs

---
 llvm/docs/RISCVUsage.rst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/docs/RISCVUsage.rst b/llvm/docs/RISCVUsage.rst
index ae043315aaae20..c9e99c9b98e371 100644
--- a/llvm/docs/RISCVUsage.rst
+++ b/llvm/docs/RISCVUsage.rst
@@ -244,7 +244,7 @@ LLVM supports (to various degrees) a number of experimental extensions.  All exp
 The primary goal of experimental support is to assist in the process of ratification by providing an existence proof of an implementation, and simplifying efforts to validate the value of a proposed extension against large code bases.  Experimental extensions are expected to either transition to ratified status, or be eventually removed.  The decision on whether to accept an experimental extension is currently done on an entirely case by case basis; if you want to propose one, attending the bi-weekly RISC-V sync-up call is strongly advised.
 
 ``experimental-ssnpm``, ``experimental-smnpm``, ``experimental-smmpm``, ``experimental-sspm``, ``experimental-supm``
-  LLVM implements the `v0.8.1 draft specification <https://github.com/riscv/riscv-j-extension/blob/master/zjpm-spec.pdf>
+  LLVM implements the `v0.8.1 draft specification <https://github.com/riscv/riscv-j-extension/blob/master/zjpm-spec.pdf>`
 
 ``experimental-zabha``
   LLVM implements assembler support for the `v1.0-rc1 draft specification <https://github.com/riscv/riscv-zabha/tree/v1.0-rc1>`_.

>From a0336e7c11a6a3f450ca9b65e83e78cf35681583 Mon Sep 17 00:00:00 2001
From: Michael Maitland <michaeltmaitland at gmail.com>
Date: Sun, 4 Feb 2024 14:47:34 -0800
Subject: [PATCH 3/3] fixup! add meaning of n in description

---
 llvm/lib/Target/RISCV/RISCVFeatures.td | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/llvm/lib/Target/RISCV/RISCVFeatures.td b/llvm/lib/Target/RISCV/RISCVFeatures.td
index 97359a987e1676..71119136379b34 100644
--- a/llvm/lib/Target/RISCV/RISCVFeatures.td
+++ b/llvm/lib/Target/RISCV/RISCVFeatures.td
@@ -883,13 +883,13 @@ def FeatureStdExtSvpbmt
 // present.
 def FeatureStdExtSsnpm
     : SubtargetFeature<"experimental-ssnpm", "HasStdExtSsnpm", "true",
-                       "'Ssnpm' (Supervisor-level Pointer Masking)">;
+                       "'Ssnpm' (Supervisor-level Pointer Masking for next lower privilege mode)">;
 
 // A machine-level extension that provides pointer masking for the next lower
 // privilege mode (S/HS if S-mode is implemented, or U-mode otherwise).
 def FeatureStdExtSmnpm
     : SubtargetFeature<"experimental-smnpm", "HasStdExtSmnpm", "true",
-                       "'Smnpm' (Machine-level Pointer Masking)">;
+                       "'Smnpm' (Machine-level Pointer Masking for next lower privilege mode)">;
 
 // A machine-level extension that provides pointer masking for M-mode.
 def FeatureStdExtSmmpm



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