[clang] [llvm] riscv: Support -mstack-protector-guard=tls (PR #108942)

via cfe-commits cfe-commits at lists.llvm.org
Tue Sep 17 01:54:29 PDT 2024


llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Keith Packard (keith-packard)

<details>
<summary>Changes</summary>

Add support for using a thread-local variable with a specified offsetfor holding the stack guard canary value.

---
Full diff: https://github.com/llvm/llvm-project/pull/108942.diff


5 Files Affected:

- (modified) clang/lib/Driver/ToolChains/Clang.cpp (+30-3) 
- (modified) clang/test/CodeGen/stack-protector-guard.c (+9) 
- (modified) clang/test/Driver/stack-protector-guard.c (+10) 
- (modified) llvm/lib/Target/RISCV/RISCVISelLowering.cpp (+8) 
- (added) llvm/test/CodeGen/RISCV/stack-guard-tls.ll (+19) 


``````````diff
diff --git a/clang/lib/Driver/ToolChains/Clang.cpp b/clang/lib/Driver/ToolChains/Clang.cpp
index 3fe4ce5d893b8d..4c7756b3883b8c 100644
--- a/clang/lib/Driver/ToolChains/Clang.cpp
+++ b/clang/lib/Driver/ToolChains/Clang.cpp
@@ -3604,7 +3604,8 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
   if (Arg *A = Args.getLastArg(options::OPT_mstack_protector_guard_EQ)) {
     StringRef Value = A->getValue();
     if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
-        !EffectiveTriple.isARM() && !EffectiveTriple.isThumb())
+        !EffectiveTriple.isARM() && !EffectiveTriple.isThumb() &&
+        !EffectiveTriple.isRISCV())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     if ((EffectiveTriple.isX86() || EffectiveTriple.isARM() ||
@@ -3644,13 +3645,28 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
           << A->getOption().getName() << Value << "sysreg global";
       return;
     }
+    if (EffectiveTriple.isRISCV()) {
+      if (Value != "tls" && Value != "global") {
+        D.Diag(diag::err_drv_invalid_value_with_suggestion)
+            << A->getOption().getName() << Value << "tls global";
+        return;
+      }
+      if (Value == "tls") {
+        if (!Args.hasArg(options::OPT_mstack_protector_guard_offset_EQ)) {
+          D.Diag(diag::err_drv_ssp_missing_offset_argument)
+              << A->getAsString(Args);
+          return;
+        }
+      }
+    }
     A->render(Args, CmdArgs);
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_mstack_protector_guard_offset_EQ)) {
     StringRef Value = A->getValue();
     if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
-        !EffectiveTriple.isARM() && !EffectiveTriple.isThumb())
+        !EffectiveTriple.isARM() && !EffectiveTriple.isThumb() &&
+        !EffectiveTriple.isRISCV())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     int Offset;
@@ -3664,12 +3680,18 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
           << A->getOption().getName() << Value;
       return;
     }
+    if (EffectiveTriple.isRISCV() && (Offset <= -2048 || Offset >= 2048)) {
+      D.Diag(diag::err_drv_invalid_int_value)
+          << A->getOption().getName() << Value;
+      return;
+    }
     A->render(Args, CmdArgs);
   }
 
   if (Arg *A = Args.getLastArg(options::OPT_mstack_protector_guard_reg_EQ)) {
     StringRef Value = A->getValue();
-    if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64())
+    if (!EffectiveTriple.isX86() && !EffectiveTriple.isAArch64() &&
+        !EffectiveTriple.isRISCV())
       D.Diag(diag::err_drv_unsupported_opt_for_target)
           << A->getAsString(Args) << TripleStr;
     if (EffectiveTriple.isX86() && (Value != "fs" && Value != "gs")) {
@@ -3681,6 +3703,11 @@ static void RenderSSPOptions(const Driver &D, const ToolChain &TC,
       D.Diag(diag::err_drv_invalid_value) << A->getOption().getName() << Value;
       return;
     }
+    if (EffectiveTriple.isRISCV() && Value != "tp") {
+      D.Diag(diag::err_drv_invalid_value_with_suggestion)
+          << A->getOption().getName() << Value << "tp";
+      return;
+    }
     A->render(Args, CmdArgs);
   }
 
diff --git a/clang/test/CodeGen/stack-protector-guard.c b/clang/test/CodeGen/stack-protector-guard.c
index 5839ab06033a15..81e0ddc8753966 100644
--- a/clang/test/CodeGen/stack-protector-guard.c
+++ b/clang/test/CodeGen/stack-protector-guard.c
@@ -9,6 +9,9 @@
 // RUN: %clang_cc1 -mstack-protector-guard=sysreg -triple aarch64-linux-gnu \
 // RUN:   -mstack-protector-guard-offset=1024 -mstack-protector-guard-reg=sp_el0 \
 // RUN:   -emit-llvm %s -o - | FileCheck %s --check-prefix=AARCH64
+// RUN: %clang_cc1 -mstack-protector-guard=tls -triple riscv64-unknown-elf \
+// RUN:   -mstack-protector-guard-offset=44 -mstack-protector-guard-reg=tp \
+// RUN:   -emit-llvm %s -o - | FileCheck %s --check-prefix=RISCV
 void foo(int*);
 void bar(int x) {
   int baz[x];
@@ -23,3 +26,9 @@ void bar(int x) {
 // AARCH64: [[ATTR1]] = !{i32 1, !"stack-protector-guard", !"sysreg"}
 // AARCH64: [[ATTR2]] = !{i32 1, !"stack-protector-guard-reg", !"sp_el0"}
 // AARCH64: [[ATTR3]] = !{i32 1, !"stack-protector-guard-offset", i32 1024}
+
+// RISCV: !llvm.module.flags = !{{{.*}}[[ATTR1:![0-9]+]], [[ATTR2:![0-9]+]], [[ATTR3:![0-9]+]], [[ATTR4:![0-9]+]]}
+// RISCV: [[ATTR1]] = !{i32 1, !"stack-protector-guard", !"tls"}
+// RISCV: [[ATTR2]] = !{i32 1, !"stack-protector-guard-reg", !"tp"}
+// RISCV: [[ATTR3]] = !{i32 1, !"stack-protector-guard-offset", i32 44}
+
diff --git a/clang/test/Driver/stack-protector-guard.c b/clang/test/Driver/stack-protector-guard.c
index af4e11f8eaabce..be95d1d5798e3c 100644
--- a/clang/test/Driver/stack-protector-guard.c
+++ b/clang/test/Driver/stack-protector-guard.c
@@ -85,3 +85,13 @@
 // CHECK-AARCH64: "-cc1" {{.*}}"-mstack-protector-guard=sysreg" "-mstack-protector-guard-offset=0" "-mstack-protector-guard-reg=sp_el0"
 // INVALID-VALUE-AARCH64: error: invalid value 'tls' in 'mstack-protector-guard=', expected one of: sysreg global
 // INVALID-REG-AARCH64: error: invalid value 'foo' in 'mstack-protector-guard-reg='
+
+// RUN: not %clang -target riscv64-unknown-elf -mstack-protector-guard=tls %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=MISSING-OFFSET %s
+
+// RUN: not %clang -target riscv64-unknown-elf -mstack-protector-guard-offset=1048576 %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=INVALID-OFFSET %s
+
+// RUN: not %clang -target riscv64-unknown-elf -mstack-protector-guard=sysreg %s 2>&1 | \
+// RUN:   FileCheck -check-prefix=INVALID-VALUE2 %s
+
diff --git a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
index 7d2a7b20ba2508..c52ef550495052 100644
--- a/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ b/llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -21228,6 +21228,14 @@ Value *RISCVTargetLowering::getIRStackGuard(IRBuilderBase &IRB) const {
   if (Subtarget.isTargetAndroid())
     return useTpOffset(IRB, -0x18);
 
+  Module *M = IRB.GetInsertBlock()->getParent()->getParent();
+
+  if (M->getStackProtectorGuard() == "tls") {
+    // Specially, some users may customize the base reg and offset.
+    int Offset = M->getStackProtectorGuardOffset();
+    return useTpOffset(IRB, Offset);
+  }
+
   return TargetLowering::getIRStackGuard(IRB);
 }
 
diff --git a/llvm/test/CodeGen/RISCV/stack-guard-tls.ll b/llvm/test/CodeGen/RISCV/stack-guard-tls.ll
new file mode 100644
index 00000000000000..a42feeb7e12fba
--- /dev/null
+++ b/llvm/test/CodeGen/RISCV/stack-guard-tls.ll
@@ -0,0 +1,19 @@
+; RUN: llc -mtriple=riscv64-unknown-elf < %s | \
+; RUN: FileCheck %s
+
+declare void @baz(ptr)
+
+define void @foo(i64 %t) sspstrong {
+  %vla = alloca i32, i64 %t, align 4
+  call void @baz(ptr nonnull %vla)
+  ret void
+}
+
+!llvm.module.flags = !{!0, !1, !2}
+!0 = !{i32 2, !"stack-protector-guard", !"tls"}
+!1 = !{i32 1, !"stack-protector-guard-reg", !"tp"}
+!2 = !{i32 2, !"stack-protector-guard-offset", i32 500}
+
+; CHECK: ld [[REG1:.*]], 500(tp)
+; CHECK: call baz
+; CHECK: ld [[REG2:.*]], 500(tp)

``````````

</details>


https://github.com/llvm/llvm-project/pull/108942


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