Add some support for diagnosing possibly mismatched constraint, type size and

modifiers. (From an idea by Eric...)
<rdar://problem/12284092>

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@166647 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 56cb2060421c32537e7b93300490759c06a288b2..cd7fb00c99c211be61f872cf9c3abf6bf0fe86de 100644 (file)
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -5146,6 +5146,9 @@ let CategoryName = "Inline Assembly Issue" in {
     "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 warn_mismatched_size_modifier : Warning<
+    "the size being stored may not be the size intended, use a modifier to "
+    "specify the size">;
 
   def err_inline_ms_asm_parsing : Error<"%0">;
 }

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 ba96185f72d1562ba6706ae27a3aa01d288bebae..960a2858e41a2528f71d270b8e2ade771fc44f04 100644 (file)
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -3315,6 +3315,29 @@ 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 3a5f40c74fac126faa98ddc6f2ae2105d3e8dc9f..138d671470168a63fe834da3517b240f7f78fe37 100644 (file)
--- a/lib/Sema/SemaStmtAsm.cpp
+++ b/lib/Sema/SemaStmtAsm.cpp
@@ -208,6 +208,54 @@ 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_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/Misc/warning-flags.c b/test/Misc/warning-flags.c
index 302abccc59492441f8a7c87b2a2797afdc339b20..fa73db11d861dd0e554d5053dbffa6a4904fb4bc 100644 (file)
--- a/test/Misc/warning-flags.c
+++ b/test/Misc/warning-flags.c
@@ -18,7 +18,7 @@ This test serves two purposes:
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (154):
+CHECK: Warnings without flags (155):
 CHECK-NEXT:   ext_delete_void_ptr_operand
 CHECK-NEXT:   ext_enum_friend
 CHECK-NEXT:   ext_expected_semi_decl_list
@@ -100,6 +100,7 @@ CHECK-NEXT:   warn_many_braces_around_scalar_init
 CHECK-NEXT:   warn_maynot_respond
 CHECK-NEXT:   warn_method_param_redefinition
 CHECK-NEXT:   warn_mismatched_exception_spec
+CHECK-NEXT:   warn_mismatched_size_modifier
 CHECK-NEXT:   warn_missing_case_for_condition
 CHECK-NEXT:   warn_missing_dependent_template_keyword
 CHECK-NEXT:   warn_missing_exception_specification