From 18f3a14e1328c813fa5dbacc9bb931d22f0669cd Mon Sep 17 00:00:00 2001
From: Craig Topper <craig.topper@sifive.com>
Date: Mon, 10 May 2021 11:30:45 -0700
Subject: [PATCH] [RISCV] Validate the SEW and LMUL operands to
 __builtin_rvv_vsetvli(max)

These are required to be constants, this patch makes sure they
are in the accepted range of values.

These are usually created by wrappers in the riscv_vector.h header
which should always be correct. This patch protects against a user
using the builtin directly.

Reviewed By: khchen

Differential Revision: https://reviews.llvm.org/D102086
---
 clang/include/clang/Basic/DiagnosticSemaKinds.td |  2 ++
 clang/include/clang/Sema/Sema.h                  |  1 +
 clang/lib/Sema/SemaChecking.cpp                  | 34 +++++++++++++++++++++++-
 clang/test/CodeGen/RISCV/rvv_errors.c            | 10 +++++++
 4 files changed, 46 insertions(+), 1 deletion(-)
 create mode 100644 clang/test/CodeGen/RISCV/rvv_errors.c

diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 99b4169..f78940a 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -11267,4 +11267,6 @@ def warn_tcb_enforcement_violation : Warning<
 // RISC-V builtin required extension warning
 def err_riscv_builtin_requires_extension : Error<
   "builtin requires '%0' extension support to be enabled">;
+def err_riscv_builtin_invalid_lmul : Error<
+  "LMUL argument must be in the range [0,3] or [5,7]">;
 } // end of sema component.
diff --git a/clang/include/clang/Sema/Sema.h b/clang/include/clang/Sema/Sema.h
index d2a0745..53ff0f1 100644
--- a/clang/include/clang/Sema/Sema.h
+++ b/clang/include/clang/Sema/Sema.h
@@ -12539,6 +12539,7 @@ private:
   bool CheckPPCBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                    CallExpr *TheCall);
   bool CheckAMDGCNBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall);
+  bool CheckRISCVLMUL(CallExpr *TheCall, unsigned ArgNum);
   bool CheckRISCVBuiltinFunctionCall(const TargetInfo &TI, unsigned BuiltinID,
                                      CallExpr *TheCall);
 
diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
index fec02b8..f3f1ccd 100644
--- a/clang/lib/Sema/SemaChecking.cpp
+++ b/clang/lib/Sema/SemaChecking.cpp
@@ -3417,6 +3417,26 @@ bool Sema::CheckAMDGCNBuiltinFunctionCall(unsigned BuiltinID,
   return false;
 }
 
+bool Sema::CheckRISCVLMUL(CallExpr *TheCall, unsigned ArgNum) {
+  llvm::APSInt Result;
+
+  // We can't check the value of a dependent argument.
+  Expr *Arg = TheCall->getArg(ArgNum);
+  if (Arg->isTypeDependent() || Arg->isValueDependent())
+    return false;
+
+  // Check constant-ness first.
+  if (SemaBuiltinConstantArg(TheCall, ArgNum, Result))
+    return true;
+
+  int64_t Val = Result.getSExtValue();
+  if ((Val >= 0 && Val <= 3) || (Val >= 5 && Val <= 7))
+    return false;
+
+  return Diag(TheCall->getBeginLoc(), diag::err_riscv_builtin_invalid_lmul)
+         << Arg->getSourceRange();
+}
+
 bool Sema::CheckRISCVBuiltinFunctionCall(const TargetInfo &TI,
                                          unsigned BuiltinID,
                                          CallExpr *TheCall) {
@@ -3448,7 +3468,19 @@ bool Sema::CheckRISCVBuiltinFunctionCall(const TargetInfo &TI,
         << TheCall->getSourceRange() << StringRef(FeatureStr);
   }
 
-  return FeatureMissing;
+  if (FeatureMissing)
+    return true;
+
+  switch (BuiltinID) {
+  case RISCV::BI__builtin_rvv_vsetvli:
+    return SemaBuiltinConstantArgRange(TheCall, 1, 0, 3) ||
+           CheckRISCVLMUL(TheCall, 2);
+  case RISCV::BI__builtin_rvv_vsetvlimax:
+    return SemaBuiltinConstantArgRange(TheCall, 0, 0, 3) ||
+           CheckRISCVLMUL(TheCall, 1);
+  }
+
+  return false;
 }
 
 bool Sema::CheckSystemZBuiltinFunctionCall(unsigned BuiltinID,
diff --git a/clang/test/CodeGen/RISCV/rvv_errors.c b/clang/test/CodeGen/RISCV/rvv_errors.c
new file mode 100644
index 0000000..40ec544
--- /dev/null
+++ b/clang/test/CodeGen/RISCV/rvv_errors.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 %s -triple=riscv64 -target-feature +experimental-v -fsyntax-only -verify
+
+void test() {
+  __builtin_rvv_vsetvli(1, 7, 0); // expected-error {{argument value 7 is outside the valid range [0, 3]}}
+  __builtin_rvv_vsetvlimax(-1, 0); // expected-error {{argument value 18446744073709551615 is outside the valid range [0, 3]}}
+  __builtin_rvv_vsetvli(1, 0, 4); // expected-error {{LMUL argument must be in the range [0,3] or [5,7]}}
+  __builtin_rvv_vsetvlimax(0, 4); // expected-error {{LMUL argument must be in the range [0,3] or [5,7]}}
+  __builtin_rvv_vsetvli(1, 0, 8); // expected-error {{LMUL argument must be in the range [0,3] or [5,7]}}
+  __builtin_rvv_vsetvlimax(0, -1); // expected-error {{LMUL argument must be in the range [0,3] or [5,7]}}
+}
-- 
2.7.4