[llvm-commits] [llvm] r131024 - in /llvm/trunk: lib/CodeGen/RegAllocBasic.cpp lib/CodeGen/RegAllocGreedy.cpp test/CodeGen/X86/inline-asm-error.ll

[Jakob Stoklund Olesen]

Author: stoklund
Date: Fri May  6 16:58:30 2011
New Revision: 131024

URL: http://llvm.org/viewvc/llvm-project?rev=131024&view=rev
Log:
Emit a proper error message when register allocators run out of registers.

This can't be just an assertion, users can always write impossible inline
assembly. Such an assembly statement should be included in the error message.

Added:
    llvm/trunk/test/CodeGen/X86/inline-asm-error.ll
Modified:
    llvm/trunk/lib/CodeGen/RegAllocBasic.cpp
    llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp

Modified: llvm/trunk/lib/CodeGen/RegAllocBasic.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocBasic.cpp?rev=131024&r1=131023&r2=131024&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocBasic.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocBasic.cpp Fri May  6 16:58:30 2011
@@ -321,6 +321,23 @@
     VirtRegVec SplitVRegs;
     unsigned AvailablePhysReg = selectOrSplit(*VirtReg, SplitVRegs);
 
+    if (AvailablePhysReg == ~0u) {
+      // selectOrSplit failed to find a register!
+      std::string msg;
+      raw_string_ostream Msg(msg);
+      Msg << "Ran out of registers during register allocation!"
+             "\nCannot allocate: " << *VirtReg;
+      for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(VirtReg->reg);
+      MachineInstr *MI = I.skipInstruction();) {
+        if (!MI->isInlineAsm())
+          continue;
+        Msg << "\nPlease check your inline asm statement for "
+          "invalid constraints:\n";
+        MI->print(Msg, &VRM->getMachineFunction().getTarget());
+      }
+      report_fatal_error(Msg.str());
+    }
+
     if (AvailablePhysReg)
       assign(*VirtReg, AvailablePhysReg);
 
@@ -498,8 +515,11 @@
     // Tell the caller to allocate to this newly freed physical register.
     return *PhysRegI;
   }
+
   // No other spill candidates were found, so spill the current VirtReg.
   DEBUG(dbgs() << "spilling: " << VirtReg << '\n');
+  if (!VirtReg.isSpillable())
+    return ~0u;
   LiveRangeEdit LRE(VirtReg, SplitVRegs);
   spiller().spill(LRE);
 

Modified: llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp?rev=131024&r1=131023&r2=131024&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegAllocGreedy.cpp Fri May  6 16:58:30 2011
@@ -1380,7 +1380,10 @@
     return 0;
   }
 
-  assert(Stage < RS_Spill && "Cannot allocate after spilling");
+  // If we couldn't allocate a register from spilling, there is probably some
+  // invalid inline assembly. The base class wil report it.
+  if (Stage >= RS_Spill)
+    return ~0u;
 
   // Try splitting VirtReg or interferences.
   unsigned PhysReg = trySplit(VirtReg, Order, NewVRegs);

Added: llvm/trunk/test/CodeGen/X86/inline-asm-error.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/inline-asm-error.ll?rev=131024&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/inline-asm-error.ll (added)
+++ llvm/trunk/test/CodeGen/X86/inline-asm-error.ll Fri May  6 16:58:30 2011
@@ -0,0 +1,17 @@
+; RUN: not llc -march x86 -regalloc=fast       < %s 2> %t1
+; RUN: not llc -march x86 -regalloc=basic      < %s 2> %t2
+; RUN: not llc -march x86 -regalloc=greedy     < %s 2> %t3
+; RUN: FileCheck %s < %t1
+; RUN: FileCheck %s < %t2
+; RUN: FileCheck %s < %t3
+
+; The register allocator must fail on this function, and it should print the
+; inline asm in the diagnostic.
+; CHECK: LLVM ERROR: Ran out of registers during register allocation!
+; CHECK: INLINEASM <es:hello world>
+
+define void @f(i32 %x0, i32 %x1, i32 %x2, i32 %x3, i32 %x4, i32 %x5, i32 %x6, i32 %x7, i32 %x8, i32 %x9) nounwind ssp {
+entry:
+  tail call void asm sideeffect "hello world", "r,r,r,r,r,r,r,r,r,r,~{dirflag},~{fpsr},~{flags}"(i32 %x0, i32 %x1, i32 %x2, i32 %x3, i32 %x4, i32 %x5, i32 %x6, i32 %x7, i32 %x8, i32 %x9) nounwind
+  ret void
+}