Recommit Eric's code to validate ASM string's constraints and modifiers.

This code checks the ASM string to see if the output size is able to fit within
the variable specified as the output. For instance, scalar-to-vector conversions
may not really work. It's on by default, but can be turned off with a flag if
you think you know what you're doing.

This is placed under a flag ('-Wasm-operand-widths') and flag group ('-Wasm').

<rdar://problem/12284092>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@166737 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticGroups.td b/include/clang/Basic/DiagnosticGroups.td
index ec4deaafbecab38c8b59febd4ffdb2aa2fb6529f..16356336f132e533ffcbf8f1fa274faf62aa3ac7 100644 (file)
--- a/include/clang/Basic/DiagnosticGroups.td
+++ b/include/clang/Basic/DiagnosticGroups.td
@@ -481,3 +481,9 @@ def ObjCStringComparison : DiagGroup<"objc-string-compare">;
 def ObjCLiteralComparison : DiagGroup<"objc-literal-compare", [
     ObjCStringComparison
   ]>;
+
+// Inline ASM warnings.
+def ASMOperandWidths : DiagGroup<"asm-operand-widths">;
+def ASM : DiagGroup<"asm", [
+    ASMOperandWidths
+  ]>;

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 56cb2060421c32537e7b93300490759c06a288b2..97a31c16838f44f36a5024aed941d15f6957a6e7 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5136,18 +5136,20 @@ let CategoryName = "Inline Assembly Issue" in {
     "%diff{$ matching output with type $|}0,1">;
   def err_asm_unknown_register_name : Error<"unknown register name '%0' in asm">;
   def err_asm_empty : Error<"__asm used with no assembly instructions">;
-  def warn_asm_label_on_auto_decl : Warning<
-    "ignored asm label '%0' on automatic variable">;
   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_inline_ms_asm_parsing : Error<"%0">;
 
+  def warn_asm_label_on_auto_decl : Warning<
+    "ignored asm label '%0' on automatic variable">;
   def warn_invalid_asm_cast_lvalue : Warning<
     "invalid use of a cast in a inline asm context requiring an l-value: "
     "accepted due to -fheinous-gnu-extensions, but clang may remove support "
     "for this in the future">;
-
-  def err_inline_ms_asm_parsing : Error<"%0">;
+  def warn_asm_mismatched_size_modifier : Warning<
+    "the size being stored is truncated, use a modifier to specify the size">,
+    InGroup<ASMOperandWidths>;
 }
 
 let CategoryName = "Semantic Issue" in {

diff --git a/include/clang/Basic/TargetInfo.h b/include/clang/Basic/TargetInfo.h
index ea520e8f8289377f30063a437891c60ec31a1a09..b0e58050d5d959b2668a14ef920756e3a89c7702 100644 (file)
--- a/include/clang/Basic/TargetInfo.h
+++ b/include/clang/Basic/TargetInfo.h
@@ -517,6 +517,11 @@ public:
   bool validateInputConstraint(ConstraintInfo *OutputConstraints,
                                unsigned NumOutputs,
                                ConstraintInfo &info) const;
+  virtual bool validateConstraintModifier(StringRef /*Constraint*/,
+                                          const char /*Modifier*/,
+                                          unsigned /*Size*/) const {
+    return true;
+  }
   bool resolveSymbolicName(const char *&Name,
                            ConstraintInfo *OutputConstraints,
                            unsigned NumOutputs, unsigned &Index) const;

diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 9b758d1c21235cdd97d568f3405995730da303a7..1ab151e5efdc1070dee0e7906d190d23d256e3a1 100644 (file)
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -3315,6 +3315,30 @@ public:
     }
     return R;
   }
+  virtual bool validateConstraintModifier(StringRef Constraint,
+                                          const char Modifier,
+                                          unsigned Size) const {
+    // Strip off constraint modifiers.
+    while (Constraint[0] == '=' ||
+           Constraint[0] == '+' ||
+           Constraint[0] == '&')
+      Constraint = Constraint.substr(1);
+
+    switch (Constraint[0]) {
+    default: break;
+    case 'r': {
+      switch (Modifier) {
+      default:
+        return Size == 32;
+      case 'q':
+        // A register of size 32 cannot fit a vector type.
+        return false;
+      }
+    }
+    }
+
+    return true;
+  }
   virtual const char *getClobbers() const {
     // FIXME: Is this really right?
     return "";

diff --git a/lib/Sema/SemaStmtAsm.cpp b/lib/Sema/SemaStmtAsm.cpp
index 8e6b81472f8710e36237f2cd9aeda47af6b15cef..7c2c766e46153bc1d1a6032c60453366f99af5cd 100644 (file)
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -209,6 +209,54 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
     return StmtError();
   }
 
+  // Validate constraints and modifiers.
+  for (unsigned i = 0, e = Pieces.size(); i != e; ++i) {
+    GCCAsmStmt::AsmStringPiece &Piece = Pieces[i];
+    if (!Piece.isOperand()) continue;
+
+    // Look for the correct constraint index.
+    unsigned Idx = 0;
+    unsigned ConstraintIdx = 0;
+    for (unsigned i = 0, e = NS->getNumOutputs(); i != e; ++i, ++ConstraintIdx) {
+      TargetInfo::ConstraintInfo &Info = OutputConstraintInfos[i];
+      if (Idx == Piece.getOperandNo())
+        break;
+      ++Idx;
+
+      if (Info.isReadWrite()) {
+        if (Idx == Piece.getOperandNo())
+          break;
+        ++Idx;
+      }
+    }
+
+    for (unsigned i = 0, e = NS->getNumInputs(); i != e; ++i, ++ConstraintIdx) {
+      TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];
+      if (Idx == Piece.getOperandNo())
+        break;
+      ++Idx;
+
+      if (Info.isReadWrite()) {
+        if (Idx == Piece.getOperandNo())
+          break;
+        ++Idx;
+      }
+    }
+
+    // Now that we have the right indexes go ahead and check.
+    StringLiteral *Literal = Constraints[ConstraintIdx];
+    const Type *Ty = Exprs[ConstraintIdx]->getType().getTypePtr();
+    if (Ty->isDependentType() || Ty->isIncompleteType())
+      continue;
+
+    unsigned Size = Context.getTypeSize(Ty);
+    if (!Context.getTargetInfo()
+          .validateConstraintModifier(Literal->getString(), Piece.getModifier(),
+                                      Size))
+      Diag(Exprs[ConstraintIdx]->getLocStart(),
+           diag::warn_asm_mismatched_size_modifier);
+  }
+
   // Validate tied input operands for type mismatches.
   for (unsigned i = 0, e = InputConstraintInfos.size(); i != e; ++i) {
     TargetInfo::ConstraintInfo &Info = InputConstraintInfos[i];

diff --git a/test/CodeGen/arm-asm-warn.c b/test/CodeGen/arm-asm-warn.c
new file mode 100644 (file)
index 0000000..0c4e97a
--- /dev/null
+++ b/test/CodeGen/arm-asm-warn.c
@@ -0,0 +1,18 @@
+// REQUIRES: arm-registered-target
+// RUN: %clang_cc1 -triple armv7 %s -emit-llvm -o /dev/null
+// <rdar://problem/12284092>
+
+typedef __attribute__((neon_vector_type(2))) long long int64x2_t;
+typedef struct int64x2x4_t {
+  int64x2_t val[4];
+} int64x2x4_t;
+int64x2x4_t t2(const long long a[]) {
+  int64x2x4_t r;
+  __asm__("vldm %[a], { %q[r0], %q[r1], %q[r2], %q[r3] }"
+          : [r0] "=r"(r.val[0]), // expected-warning {{the size being stored is truncated, use a modifier to specify the size}}
+            [r1] "=r"(r.val[1]), // expected-warning {{the size being stored is truncated, use a modifier to specify the size}}
+            [r2] "=r"(r.val[2]), // expected-warning {{the size being stored is truncated, use a modifier to specify the size}}
+            [r3] "=r"(r.val[3])  // expected-warning {{the size being stored is truncated, use a modifier to specify the size}}
+          : [a] "r"(a));
+  return r;
+}