[llvm] r187470 - Fix crashing on invalid inline asm with matching constraints.

[Eric Christopher]

Author: echristo
Date: Tue Jul 30 20:26:24 2013
New Revision: 187470

URL: http://llvm.org/viewvc/llvm-project?rev=187470&view=rev
Log:
Fix crashing on invalid inline asm with matching constraints.

For a testcase like the following:

 typedef unsigned long uint64_t;

 typedef struct {
   uint64_t lo;
   uint64_t hi;
 } blob128_t;

 void add_128_to_128(const blob128_t *in, blob128_t *res) {
   asm ("PAND %1, %0" : "+Q"(*res) : "Q"(*in));
 }

where we'll fail to allocate the register for the output constraint,
our matching input constraint will not find a register to match,
and could try to search past the end of the current operands array.

On the idea that we'd like to attempt to keep compilation going
to find more errors in the module, change the error cases when
we're visiting inline asm IR to return immediately and avoid
trying to create a node in the DAG. This leaves us with only
a single error message per inline asm instruction, but allows us
to safely keep going in the general case.

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=187470&r1=187469&r2=187470&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Tue Jul 30 20:26:24 2013
@@ -6128,8 +6128,8 @@ void SelectionDAGBuilder::visitInlineAsm
         LLVMContext &Ctx = *DAG.getContext();
         Ctx.emitError(CS.getInstruction(),
                       "couldn't allocate output register for constraint '" +
-                           Twine(OpInfo.ConstraintCode) + "'");
-        break;
+                          Twine(OpInfo.ConstraintCode) + "'");
+        return;
       }
 
       // If this is an indirect operand, store through the pointer after the
@@ -6182,10 +6182,10 @@ void SelectionDAGBuilder::visitInlineAsm
           if (OpInfo.isIndirect) {
             // This happens on gcc/testsuite/gcc.dg/pr8788-1.c
             LLVMContext &Ctx = *DAG.getContext();
-            Ctx.emitError(CS.getInstruction(),  "inline asm not supported yet:"
-                          " don't know how to handle tied "
-                          "indirect register inputs");
-            report_fatal_error("Cannot handle indirect register inputs!");
+            Ctx.emitError(CS.getInstruction(), "inline asm not supported yet:"
+                                               " don't know how to handle tied "
+                                               "indirect register inputs");
+            return;
           }
 
           RegsForValue MatchedRegs;
@@ -6199,10 +6199,10 @@ void SelectionDAGBuilder::visitInlineAsm
               MatchedRegs.Regs.push_back(RegInfo.createVirtualRegister(RC));
             else {
               LLVMContext &Ctx = *DAG.getContext();
-              Ctx.emitError(CS.getInstruction(), "inline asm error: This value"
+              Ctx.emitError(CS.getInstruction(),
+                            "inline asm error: This value"
                             " type register class is not natively supported!");
-              report_fatal_error("inline asm error: This value type register "
-                                 "class is not natively supported!");
+              return;
             }
           }
           // Use the produced MatchedRegs object to
@@ -6240,8 +6240,8 @@ void SelectionDAGBuilder::visitInlineAsm
           LLVMContext &Ctx = *DAG.getContext();
           Ctx.emitError(CS.getInstruction(),
                         "invalid operand for inline asm constraint '" +
-                        Twine(OpInfo.ConstraintCode) + "'");
-          break;
+                            Twine(OpInfo.ConstraintCode) + "'");
+          return;
         }
 
         // Add information to the INLINEASM node to know about this input.
@@ -6275,8 +6275,9 @@ void SelectionDAGBuilder::visitInlineAsm
         LLVMContext &Ctx = *DAG.getContext();
         Ctx.emitError(CS.getInstruction(),
                       "Don't know how to handle indirect register inputs yet "
-                      "for constraint '" + Twine(OpInfo.ConstraintCode) + "'");
-        break;
+                      "for constraint '" +
+                          Twine(OpInfo.ConstraintCode) + "'");
+        return;
       }
 
       // Copy the input into the appropriate registers.
@@ -6284,8 +6285,8 @@ void SelectionDAGBuilder::visitInlineAsm
         LLVMContext &Ctx = *DAG.getContext();
         Ctx.emitError(CS.getInstruction(),
                       "couldn't allocate input reg for constraint '" +
-                           Twine(OpInfo.ConstraintCode) + "'");
-        break;
+                          Twine(OpInfo.ConstraintCode) + "'");
+        return;
       }
 
       OpInfo.AssignedRegs.getCopyToRegs(InOperandVal, DAG, getCurSDLoc(),