r228089 - [inlineasm] Fix an incorrect warning about register constraint and modifier.

[Akira Hatanaka]

Author: ahatanak
Date: Tue Feb  3 18:27:13 2015
New Revision: 228089

URL: http://llvm.org/viewvc/llvm-project?rev=228089&view=rev
Log:
[inlineasm] Fix an incorrect warning about register constraint and modifier.

Previously, when the following piece of code was compiled, clang would
incorrectly warn that the size of "wide_two" does not match register size
specified by the constraint and modifier":

long wide_two = two;
asm ("%w0 %1" : "+r" (one), "+r"(wide_two));

This was caused by a miscalculation of ConstraintIdx in Sema::ActOnGCCAsmStmt.

This commit fixes PR21270 and rdar://problem/18668354.

Modified:
    cfe/trunk/lib/Sema/SemaStmtAsm.cpp
    cfe/trunk/test/Sema/inline-asm-validate-aarch64.c

Modified: cfe/trunk/lib/Sema/SemaStmtAsm.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmtAsm.cpp?rev=228089&r1=228088&r2=228089&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmtAsm.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmtAsm.cpp Tue Feb  3 18:27:13 2015
@@ -313,32 +313,22 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceL
     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;
+    unsigned ConstraintIdx = Piece.getOperandNo();
+    unsigned NumOperands = NS->getNumOutputs() + NS->getNumInputs();
 
-      if (Info.isReadWrite()) {
-        if (Idx == Piece.getOperandNo())
-          break;
-        ++Idx;
-      }
-    }
+    // Look for the (ConstraintIdx - NumOperands + 1)th constraint with
+    // modifier '+'.
+    if (ConstraintIdx >= NumOperands) {
+      unsigned I = 0, E = NS->getNumOutputs();
 
-    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())
+      for (unsigned Cnt = ConstraintIdx - NumOperands; I != E; ++I)
+        if (OutputConstraintInfos[I].isReadWrite() && Cnt-- == 0) {
+          ConstraintIdx = I;
           break;
-        ++Idx;
-      }
+        }
+
+      assert(I != E && "Invalid operand number should have been caught in "
+                       " AnalyzeAsmString");
     }
 
     // Now that we have the right indexes go ahead and check.

Modified: cfe/trunk/test/Sema/inline-asm-validate-aarch64.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/inline-asm-validate-aarch64.c?rev=228089&r1=228088&r2=228089&view=diff
==============================================================================
--- cfe/trunk/test/Sema/inline-asm-validate-aarch64.c (original)
+++ cfe/trunk/test/Sema/inline-asm-validate-aarch64.c Tue Feb  3 18:27:13 2015
@@ -36,3 +36,19 @@ uint8_t constraint_r_symbolic_macro(uint
 
   return byte;
 }
+
+// CHECK: warning: value size does not match register size specified by the constraint and modifier
+// CHECK: asm ("%w0 %w1 %2" : "+r" (one) : "r" (wide_two));
+// CHECK: note: use constraint modifier "w"
+// CHECK: fix-it:{{.*}}:{47:17-47:19}:"%w2"
+
+void read_write_modifier0(int one, int two) {
+  long wide_two = two;
+  asm ("%w0 %w1 %2" : "+r" (one) : "r" (wide_two));
+}
+
+// CHECK-NOT: warning: 
+void read_write_modifier1(int one, int two) {
+  long wide_two = two;
+  asm ("%w0 %1" : "+r" (one), "+r" (wide_two));
+}