Merging r355491:

------------------------------------------------------------------------
r355491 | hans | 2019-03-06 11:26:19 +0100 (Wed, 06 Mar 2019) | 9 lines

Inline asm constraints: allow ICE-like pointers for the "n" constraint (PR40890)

Apparently GCC allows this, and there's code relying on it (see bug).

The idea is to allow expression that would have been allowed if they
were cast to int. So I based the code on how such a cast would be done
(the CK_PointerToIntegral case in IntExprEvaluator::VisitCastExpr()).

Differential Revision: https://reviews.llvm.org/D58821
------------------------------------------------------------------------

git-svn-id: https://llvm.org/svn/llvm-project/cfe/branches/release_80@355674 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/AST/APValue.h b/include/clang/AST/APValue.h
index d4057c9da5f381dad331ceae47253aef101c4723..055f13f3620b4c9cae2d303e8d9f3fcc8b846fb5 100644 (file)
--- a/include/clang/AST/APValue.h
+++ b/include/clang/AST/APValue.h
@@ -257,6 +257,12 @@ public:
     return const_cast<APValue*>(this)->getInt();
   }
 
+  /// Try to convert this value to an integral constant. This works if it's an
+  /// integer, null pointer, or offset from a null pointer. Returns true on
+  /// success.
+  bool toIntegralConstant(APSInt &Result, QualType SrcTy,
+                          const ASTContext &Ctx) const;
+
   APFloat &getFloat() {
     assert(isFloat() && "Invalid accessor");
     return *(APFloat*)(char*)Data.buffer;

diff --git a/lib/AST/APValue.cpp b/lib/AST/APValue.cpp
index c05b160b8e3d9ca521f29656d5349992e28bdee5..0c2ba57f7986b847330941fc73112e12e738c33a 100644 (file)
--- a/lib/AST/APValue.cpp
+++ b/lib/AST/APValue.cpp
@@ -600,6 +600,26 @@ std::string APValue::getAsString(ASTContext &Ctx, QualType Ty) const {
   return Result;
 }
 
+bool APValue::toIntegralConstant(APSInt &Result, QualType SrcTy,
+                                 const ASTContext &Ctx) const {
+  if (isInt()) {
+    Result = getInt();
+    return true;
+  }
+
+  if (isLValue() && isNullPointer()) {
+    Result = Ctx.MakeIntValue(Ctx.getTargetNullPointerValue(SrcTy), SrcTy);
+    return true;
+  }
+
+  if (isLValue() && !getLValueBase()) {
+    Result = Ctx.MakeIntValue(getLValueOffset().getQuantity(), SrcTy);
+    return true;
+  }
+
+  return false;
+}
+
 const APValue::LValueBase APValue::getLValueBase() const {
   assert(isLValue() && "Invalid accessor");
   return ((const LV*)(const void*)Data.buffer)->Base;

diff --git a/lib/AST/ExprConstant.cpp b/lib/AST/ExprConstant.cpp
index da093ff22c123d612aceba5dfef5729b653d9fad..1f82b4add0c48ad14bc4db2731ac144bdda3c8eb 100644 (file)
--- a/lib/AST/ExprConstant.cpp
+++ b/lib/AST/ExprConstant.cpp
@@ -9821,13 +9821,12 @@ bool IntExprEvaluator::VisitCastExpr(const CastExpr *E) {
       return true;
     }
 
-    uint64_t V;
-    if (LV.isNullPointer())
-      V = Info.Ctx.getTargetNullPointerValue(SrcType);
-    else
-      V = LV.getLValueOffset().getQuantity();
+    APSInt AsInt;
+    APValue V;
+    LV.moveInto(V);
+    if (!V.toIntegralConstant(AsInt, SrcType, Info.Ctx))
+      llvm_unreachable("Can't cast this!");
 
-    APSInt AsInt = Info.Ctx.MakeIntValue(V, SrcType);
     return Success(HandleIntToIntCast(Info, E, DestType, SrcType, AsInt), E);
   }
 

diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp
index 0242b48659d10eda3c1ff95e06ab6142c6706124..b2b32759b6f730d9ec979340bf77cee15e3972fc 100644 (file)
--- a/lib/CodeGen/CGStmt.cpp
+++ b/lib/CodeGen/CGStmt.cpp
@@ -1821,8 +1821,15 @@ llvm::Value* CodeGenFunction::EmitAsmInput(
   // (immediate or symbolic), try to emit it as such.
   if (!Info.allowsRegister() && !Info.allowsMemory()) {
     if (Info.requiresImmediateConstant()) {
-      llvm::APSInt AsmConst = InputExpr->EvaluateKnownConstInt(getContext());
-      return llvm::ConstantInt::get(getLLVMContext(), AsmConst);
+      Expr::EvalResult EVResult;
+      InputExpr->EvaluateAsRValue(EVResult, getContext(), true);
+
+      llvm::APSInt IntResult;
+      if (!EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
+                                           getContext()))
+        llvm_unreachable("Invalid immediate constant!");
+
+      return llvm::ConstantInt::get(getLLVMContext(), IntResult);
     }
 
     Expr::EvalResult Result;

diff --git a/lib/Sema/SemaStmtAsm.cpp b/lib/Sema/SemaStmtAsm.cpp
index 9e084c99d0dd410a0a30d6df28145bd099a53035..2d8864bab171d4d46bb33c1a884d9f8d4ff37c6f 100644 (file)
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -383,11 +383,20 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
           return StmtError(
               Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
               << Info.getConstraintStr() << InputExpr->getSourceRange());
-        llvm::APSInt Result = EVResult.Val.getInt();
-        if (!Info.isValidAsmImmediate(Result))
+
+        // For compatibility with GCC, we also allow pointers that would be
+        // integral constant expressions if they were cast to int.
+        llvm::APSInt IntResult;
+        if (!EVResult.Val.toIntegralConstant(IntResult, InputExpr->getType(),
+                                             Context))
+          return StmtError(
+              Diag(InputExpr->getBeginLoc(), diag::err_asm_immediate_expected)
+              << Info.getConstraintStr() << InputExpr->getSourceRange());
+
+        if (!Info.isValidAsmImmediate(IntResult))
           return StmtError(Diag(InputExpr->getBeginLoc(),
                                 diag::err_invalid_asm_value_for_constraint)
-                           << Result.toString(10) << Info.getConstraintStr()
+                           << IntResult.toString(10) << Info.getConstraintStr()
                            << InputExpr->getSourceRange());
       }
 

diff --git a/test/CodeGen/x86-64-inline-asm.c b/test/CodeGen/x86-64-inline-asm.c
index bb46eda633b705675c05f32969d299022d5a3a9b..79c1bd95f38b5477de7a3c442f35b124756005bc 100644 (file)
--- a/test/CodeGen/x86-64-inline-asm.c
+++ b/test/CodeGen/x86-64-inline-asm.c
@@ -1,6 +1,7 @@
 // REQUIRES: x86-registered-target
 // RUN: %clang_cc1 -triple x86_64 %s -S -o /dev/null -DWARN -verify
 // RUN: %clang_cc1 -triple x86_64 %s -S -o /dev/null -Werror -verify
+// RUN: %clang_cc1 -triple x86_64-linux-gnu %s -S -o - | FileCheck %s
 void f() {
   asm("movaps %xmm3, (%esi, 2)");
 // expected-note@1 {{instantiated into assembly here}}
@@ -15,3 +16,17 @@ static unsigned var[1] = {};
 void g(void) { asm volatile("movd %%xmm0, %0"
                             :
                             : "m"(var)); }
+
+void pr40890(void) {
+  struct s {
+    int a, b;
+  } s;
+  __asm__ __volatile__("\n#define S_A abcd%0\n" : : "n"(&((struct s*)0)->a));
+  __asm__ __volatile__("\n#define S_B abcd%0\n" : : "n"(&((struct s*)0)->b));
+  __asm__ __volatile__("\n#define BEEF abcd%0\n" : : "n"((int*)0xdeadbeeeeeef));
+
+// CHECK-LABEL: pr40890
+// CHECK: #define S_A abcd$0
+// CHECK: #define S_B abcd$4
+// CHECK: #define BEEF abcd$244837814038255
+}

diff --git a/test/Sema/inline-asm-validate-x86.c b/test/Sema/inline-asm-validate-x86.c
index b238ab8a5038fff3cefc692beecaf948c4ebb1a7..5ea20eec05995ab26e42386308771d627b2726ff 100644 (file)
--- a/test/Sema/inline-asm-validate-x86.c
+++ b/test/Sema/inline-asm-validate-x86.c
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -triple i686 -fsyntax-only -verify %s
-// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify -DAMD64 %s
 
 void I(int i, int j) {
   static const int BelowMin = -1;
@@ -133,3 +133,21 @@ void O(int i, int j) {
           : "0"(i), "O"(64)); // expected-no-error
 }
 
+void pr40890(void) {
+  struct s {
+    int a, b;
+  };
+  static struct s s;
+  // This null pointer can be used as an integer constant expression.
+  __asm__ __volatile__("\n#define S_A abcd%0\n" : : "n"(&((struct s*)0)->a));
+  // This offset-from-null pointer can be used as an integer constant expression.
+  __asm__ __volatile__("\n#define S_B abcd%0\n" : : "n"(&((struct s*)0)->b));
+  // This pointer cannot be used as an integer constant expression.
+  __asm__ __volatile__("\n#define GLOBAL_A abcd%0\n" : : "n"(&s.a)); // expected-error{{constraint 'n' expects an integer constant expression}}
+  // Floating-point is also not okay.
+  __asm__ __volatile__("\n#define PI abcd%0\n" : : "n"(3.14f)); // expected-error{{constraint 'n' expects an integer constant expression}}
+#ifdef AMD64
+  // This arbitrary pointer is fine.
+  __asm__ __volatile__("\n#define BEEF abcd%0\n" : : "n"((int*)0xdeadbeeeeeef));
+#endif
+}