Sema: analyze I,J,K,M,N,O constraints

Add additional constraint checking for target specific behaviour for inline
assembly constraints.  We would previously silently let all arguments through
for these constraints.  In cases where the constraints were violated, we could
end up failing to select instructions and triggering assertions or worse,
silently ignoring instructions.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@225244 91177308-0d34-0410-b5e6-96231b3b80d8

6 files changed, 198 insertions, 4 deletions

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 69f86b9692..d3129bd62e 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -6178,6 +6178,8 @@ let CategoryName = "Inline Assembly Issue" in {
   def err_invalid_asm_cast_lvalue : Error<
     "invalid use of a cast in a inline asm context requiring an l-value: "
     "remove the cast or build with -fheinous-gnu-extensions">;
+  def err_invalid_asm_value_for_constraint
+      : Error <"value '%0' out of range for constraint '%1'">;
 
   def warn_asm_label_on_auto_decl : Warning<
     "ignored asm label '%0' on automatic variable">;
diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index f952d6d1d0..0ebd9c8be7 100644
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -528,18 +528,23 @@ public:
       CI_None = 0x00,
       CI_AllowsMemory = 0x01,
       CI_AllowsRegister = 0x02,
-      CI_ReadWrite = 0x04,       // "+r" output constraint (read and write).
-      CI_HasMatchingInput = 0x08 // This output operand has a matching input.
+      CI_ReadWrite = 0x04,         // "+r" output constraint (read and write).
+      CI_HasMatchingInput = 0x08,  // This output operand has a matching input.
+      CI_ImmediateConstant = 0x10, // This operand must be an immediate constant
     };
     unsigned Flags;
     int TiedOperand;
+    struct {
+      int Min;
+      int Max;
+    } ImmRange;
 
     std::string ConstraintStr;  // constraint: "=rm"
     std::string Name;           // Operand name: [foo] with no []'s.
   public:
     ConstraintInfo(StringRef ConstraintStr, StringRef Name)
-      : Flags(0), TiedOperand(-1), ConstraintStr(ConstraintStr.str()),
-      Name(Name.str()) {}
+        : Flags(0), TiedOperand(-1), ImmRange({0, 0}),
+          ConstraintStr(ConstraintStr.str()), Name(Name.str()) {}
 
     const std::string &getConstraintStr() const { return ConstraintStr; }
     const std::string &getName() const { return Name; }
@@ -562,10 +567,21 @@ public:
       return (unsigned)TiedOperand;
     }
 
+    bool requiresImmediateConstant() const {
+      return (Flags & CI_ImmediateConstant) != 0;
+    }
+    int getImmConstantMin() const { return ImmRange.Min; }
+    int getImmConstantMax() const { return ImmRange.Max; }
+
     void setIsReadWrite() { Flags |= CI_ReadWrite; }
     void setAllowsMemory() { Flags |= CI_AllowsMemory; }
     void setAllowsRegister() { Flags |= CI_AllowsRegister; }
     void setHasMatchingInput() { Flags |= CI_HasMatchingInput; }
+    void setRequiresImmediate(int Min, int Max) {
+      Flags |= CI_ImmediateConstant;
+      ImmRange.Min = Min;
+      ImmRange.Max = Max;
+    }
 
     /// \brief Indicate that this is an input operand that is tied to
     /// the specified output operand. 
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index a35298067b..f2dc84fa03 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -588,6 +588,8 @@ bool TargetInfo::validateInputConstraint(ConstraintInfo *OutputConstraints,
     case 'N':
     case 'O':
     case 'P':
+      if (!validateAsmConstraint(Name, Info))
+        return false;
       break;
     case 'r': // general register.
       Info.setAllowsRegister();
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 8c79a18d08..c74bb936e3 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -3102,6 +3102,28 @@ X86TargetInfo::validateAsmConstraint(const char *&Name,
                                      TargetInfo::ConstraintInfo &Info) const {
   switch (*Name) {
   default: return false;
+  case 'I':
+    Info.setRequiresImmediate(0, 31);
+    return true;
+  case 'J':
+    Info.setRequiresImmediate(0, 63);
+    return true;
+  case 'K':
+    Info.setRequiresImmediate(-128, 127);
+    return true;
+  case 'L':
+    // FIXME: properly analyze this constraint:
+    //  must be one of 0xff, 0xffff, or 0xffffffff
+    return true;
+  case 'M':
+    Info.setRequiresImmediate(0, 3);
+    return true;
+  case 'N':
+    Info.setRequiresImmediate(0, 255);
+    return true;
+  case 'O':
+    Info.setRequiresImmediate(0, 127);
+    return true;
   case 'Y': // first letter of a pair:
     switch (*(Name+1)) {
     default: return false;
@@ -4289,6 +4311,13 @@ public:
     case 'P': // VFP Floating point register double precision
       Info.setAllowsRegister();
       return true;
+    case 'I':
+    case 'J':
+    case 'K':
+    case 'L':
+    case 'M':
+      // FIXME
+      return true;
     case 'Q': // A memory address that is a single base register.
       Info.setAllowsMemory();
       return true;
@@ -5152,6 +5181,16 @@ public:
   bool validateAsmConstraint(const char *&Name,
                              TargetInfo::ConstraintInfo &info) const override {
     // FIXME: Implement!
+    switch (*Name) {
+    case 'I': // Signed 13-bit constant
+    case 'J': // Zero
+    case 'K': // 32-bit constant with the low 12 bits clear
+    case 'L': // A constant in the range supported by movcc (11-bit signed imm)
+    case 'M': // A constant in the range supported by movrcc (19-bit signed imm)
+    case 'N': // Same as 'K' but zext (required for SIMode)
+    case 'O': // The constant 4096
+      return true;
+    }
     return false;
   }
   const char *getClobbers() const override {
@@ -5444,6 +5483,13 @@ namespace {
     bool
     validateAsmConstraint(const char *&Name,
                           TargetInfo::ConstraintInfo &info) const override {
+      // FIXME: implement
+      switch (*Name) {
+      case 'K': // the constant 1
+      case 'L': // constant -1^20 .. 1^19
+      case 'M': // constant 1-4:
+        return true;
+      }
       // No target constraints for now.
       return false;
     }
@@ -5740,6 +5786,15 @@ public:
     case 'x': // hilo register pair
       Info.setAllowsRegister();
       return true;
+    case 'I': // Signed 16-bit constant
+    case 'J': // Integer 0
+    case 'K': // Unsigned 16-bit constant
+    case 'L': // Signed 32-bit constant, lower 16-bit zeros (for lui)
+    case 'M': // Constants not loadable via lui, addiu, or ori
+    case 'N': // Constant -1 to -65535
+    case 'O': // A signed 15-bit constant
+    case 'P': // A constant between 1 go 65535
+      return true;
     case 'R': // An address that can be used in a non-macro load or store
       Info.setAllowsMemory();
       return true;
diff --git a/lib/Sema/SemaStmtAsm.cpp b/lib/Sema/SemaStmtAsm.cpp
index afd785c5df..286c7619ed 100644
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -226,6 +226,20 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
                               diag::err_asm_invalid_lvalue_in_input)
                          << Info.getConstraintStr()
                          << InputExpr->getSourceRange());
+    } else if (Info.requiresImmediateConstant() && !Info.allowsRegister()) {
+      llvm::APSInt Result;
+      if (!InputExpr->EvaluateAsInt(Result, Context))
+        return StmtError(
+            Diag(InputExpr->getLocStart(), diag::err_asm_invalid_type_in_input)
+            << InputExpr->getType() << Info.getConstraintStr()
+            << InputExpr->getSourceRange());
+      if (Result.slt(Info.getImmConstantMin()) ||
+          Result.sgt(Info.getImmConstantMax()))
+        return StmtError(Diag(InputExpr->getLocStart(),
+                              diag::err_invalid_asm_value_for_constraint)
+                         << Result.toString(10) << Info.getConstraintStr()
+                         << InputExpr->getSourceRange());
+
     } else {
       ExprResult Result = DefaultFunctionArrayLvalueConversion(Exprs[i]);
       if (Result.isInvalid())
diff --git a/test/Sema/inline-asm-validate-x86.c b/test/Sema/inline-asm-validate-x86.c
new file mode 100644
index 0000000000..174deca80b
--- /dev/null
+++ b/test/Sema/inline-asm-validate-x86.c
@@ -0,0 +1,105 @@
+// RUN: %clang_cc1 -triple i686 -fsyntax-only -verify %s
+// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify %s
+
+void I(int i, int j) {
+  static const int BelowMin = -1;
+  static const int AboveMax = 32;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "I"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'I'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "I"(BelowMin)); // expected-error{{value '-1' out of range for constraint 'I'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "I"(AboveMax)); // expected-error{{value '32' out of range for constraint 'I'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "I"(16)); // expected-no-error
+}
+
+void J(int i, int j) {
+  static const int BelowMin = -1;
+  static const int AboveMax = 64;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "J"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'J'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "J"(BelowMin)); // expected-error{{value '-1' out of range for constraint 'J'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "J"(AboveMax)); // expected-error{{value '64' out of range for constraint 'J'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "J"(32)); // expected-no-error
+}
+
+void K(int i, int j) {
+  static const int BelowMin = -129;
+  static const int AboveMax = 128;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "K"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'K'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "K"(BelowMin)); // expected-error{{value '-129' out of range for constraint 'K'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "K"(AboveMax)); // expected-error{{value '128' out of range for constraint 'K'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "K"(96)); // expected-no-error
+}
+
+void M(int i, int j) {
+  static const int BelowMin = -1;
+  static const int AboveMax = 4;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "M"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'M'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "M"(BelowMin)); // expected-error{{value '-1' out of range for constraint 'M'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "M"(AboveMax)); // expected-error{{value '4' out of range for constraint 'M'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "M"(2)); // expected-no-error
+}
+
+void N(int i, int j) {
+  static const int BelowMin = -1;
+  static const int AboveMax = 256;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "N"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'N'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "N"(BelowMin)); // expected-error{{value '-1' out of range for constraint 'N'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "N"(AboveMax)); // expected-error{{value '256' out of range for constraint 'N'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "N"(128)); // expected-no-error
+}
+
+void O(int i, int j) {
+  static const int BelowMin = -1;
+  static const int AboveMax = 128;
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "O"(j)); // expected-error{{invalid type 'int' in asm input for constraint 'O'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "O"(BelowMin)); // expected-error{{value '-1' out of range for constraint 'O'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "O"(AboveMax)); // expected-error{{value '128' out of range for constraint 'O'}}
+  __asm__("xorl %0,%2"
+          : "=r"(i)
+          : "0"(i), "O"(64)); // expected-no-error
+}
+