Enable implicit fallthrough warning (#43397)

* Enable implicit fallthrough warning This change enables warnings for implicit fallthrough in switch cases and fixes all the cases where the warning was reported. It also fixes some places where the fall through was incorrect. Fortunately, these places were not causing functional issues.
dotnet · Oct 21, 2020 · dc7b1d2 · dc7b1d2
1 parent 159a6ea
commit dc7b1d2
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Showing 94 changed files with 380 additions and 247 deletions.
diff --git a/eng/native/configurecompiler.cmake b/eng/native/configurecompiler.cmake
@@ -324,6 +324,11 @@ if (CLR_CMAKE_HOST_UNIX)
   add_compile_options(-Wno-unused-function)
   add_compile_options(-Wno-tautological-compare)
 
+  check_cxx_compiler_flag(-Wimplicit-fallthrough COMPILER_SUPPORTS_W_IMPLICIT_FALLTHROUGH)
+  if (COMPILER_SUPPORTS_W_IMPLICIT_FALLTHROUGH)
+    add_compile_options(-Wimplicit-fallthrough)
+  endif()
+
   #These seem to indicate real issues
   add_compile_options($<$<COMPILE_LANGUAGE:CXX>:-Wno-invalid-offsetof>)
 

diff --git a/src/coreclr/src/ToolBox/superpmi/mcs/verbildump.cpp b/src/coreclr/src/ToolBox/superpmi/mcs/verbildump.cpp
@@ -893,6 +893,7 @@ void DumpILToConsoleBare(unsigned char* ilCode, int len)
                         LogError("unknown ilCode 0xfe%2x at offset %d in MethodGen::PrettyPrint", ilCode[i], i);
                         break;
                 }
+                break;
             default:
                 LogError("unknown ilCode 0x%02x at offset %d in MethodGen::PrettyPrint", ilCode[i], i);
                 break;

diff --git a/src/coreclr/src/classlibnative/bcltype/varargsnative.cpp b/src/coreclr/src/classlibnative/bcltype/varargsnative.cpp
@@ -575,7 +575,8 @@ VarArgsNative::GetNextArgHelper(
             }
 #endif
 
-        // fall through
+            FALLTHROUGH;
+
         case ELEMENT_TYPE_CLASS: {
             value->type = data->SigPtr.GetTypeHandleThrowing(data->ArgCookie->pModule, &typeContext);
 

diff --git a/src/coreclr/src/debug/di/rstype.cpp b/src/coreclr/src/debug/di/rstype.cpp
@@ -590,7 +590,7 @@ HRESULT CordbType::MkType(CordbAppDomain * pAppDomain,
 
       pClass->SetIsValueClass(true);
       pClass->SetIsValueClassKnown(true);
-      // drop through
+      FALLTHROUGH;
 
     case ELEMENT_TYPE_CLASS:
         {
@@ -2009,6 +2009,7 @@ void CordbType::TypeToExpandedTypeData(DebuggerIPCE_ExpandedTypeData *data)
         }
     case ELEMENT_TYPE_END:
         _ASSERTE(!"bad element type!");
+        break;
 
     default:
         data->elementType = m_elementType;
@@ -2389,6 +2390,7 @@ HRESULT CordbType::GetTypeID(COR_TYPEID *pId)
         case ELEMENT_TYPE_BYREF:
         case ELEMENT_TYPE_FNPTR:
             IfFailThrow(CORDBG_E_UNSUPPORTED);
+            break;
         default:
             _ASSERTE(!"unexpected element type!");
             IfFailThrow(CORDBG_E_UNSUPPORTED);

diff --git a/src/coreclr/src/debug/ee/amd64/amd64walker.cpp b/src/coreclr/src/debug/ee/amd64/amd64walker.cpp
@@ -580,6 +580,7 @@ static int opSize(Amd64InstrDecode::InstrForm form, int pp, bool W, bool L, bool
     // P_M6B_or_M4B
     case Amd64InstrDecode::InstrForm::MOnly_P_M6B_or_M4B:
         opSize = P ? 6 : 4;
+        break;
     // M4B
     case Amd64InstrDecode::InstrForm::M1st_M4B:
     case Amd64InstrDecode::InstrForm::M1st_M4B_I1B:
@@ -833,7 +834,7 @@ void NativeWalker::DecodeInstructionForPatchSkip(const BYTE *address, Instructio
                 opCodeMap = Primary;
                 break;
             }
-            // Fall through
+            FALLTHROUGH;
         case 0xc4: // Vex 3-byte
             opCodeMap = (OpcodeMap)(int(address[0]) << 8 | (address[1] & 0x1f));
             // W is the top bit of opcode2.
@@ -965,7 +966,7 @@ void NativeWalker::DecodeInstructionForPatchSkip(const BYTE *address, Instructio
                     case 2:
                     case 3:
                         pInstrAttrib->m_fIsCall = true;
-                        // fall through
+                        FALLTHROUGH;
                     case 4:
                     case 5:
                         pInstrAttrib->m_fIsAbsBranch = true;

diff --git a/src/coreclr/src/debug/ee/controller.cpp b/src/coreclr/src/debug/ee/controller.cpp
@@ -5883,7 +5883,7 @@ bool DebuggerStepper::TrapStep(ControllerStackInfo *info, bool in)
                 // the case we want to use...
                 fIsJump = true;
 
-                // fall through...
+                FALLTHROUGH;
 
             case WALK_CALL:
                 LOG((LF_CORDB,LL_INFO10000, "DC::TS:Imm:WALK_CALL ip=%p nextip=%p skipip=%p\n", walker.GetIP(), walker.GetNextIP(), walker.GetSkipIP()));

diff --git a/src/coreclr/src/debug/ee/debugger.cpp b/src/coreclr/src/debug/ee/debugger.cpp
@@ -10722,6 +10722,7 @@ bool Debugger::HandleIPCEvent(DebuggerIPCEvent * pEvent)
         //
         // For regular (non-jit) attach, fall through to do an async break.
         //
+        FALLTHROUGH;
 
     case DB_IPCE_ASYNC_BREAK:
         {
@@ -12138,7 +12139,7 @@ void Debugger::TypeHandleToExpandedTypeInfo(AreValueTypesBoxed boxed,
     case ELEMENT_TYPE_VALUETYPE:
         if (boxed == OnlyPrimitivesUnboxed || boxed == AllBoxed)
             res->elementType = ELEMENT_TYPE_CLASS;
-        // drop through
+        FALLTHROUGH;
 
     case ELEMENT_TYPE_CLASS:
         {

diff --git a/src/coreclr/src/gc/unix/gcenv.unix.cpp b/src/coreclr/src/gc/unix/gcenv.unix.cpp
@@ -28,6 +28,12 @@
 #undef min
 #undef max
 
+#if __has_cpp_attribute(fallthrough)
+#define FALLTHROUGH [[fallthrough]]
+#else
+#define FALLTHROUGH
+#endif
+
 #include <algorithm>
 
 #if HAVE_SYS_TIME_H
@@ -792,8 +798,10 @@ bool ReadMemoryValueFromFile(const char* filename, uint64_t* val)
     {
     case 'g':
     case 'G': multiplier = 1024;
+              FALLTHROUGH;
     case 'm':
     case 'M': multiplier = multiplier * 1024;
+              FALLTHROUGH;
     case 'k':
     case 'K': multiplier = multiplier * 1024;
     }

diff --git a/src/coreclr/src/ilasm/assem.cpp b/src/coreclr/src/ilasm/assem.cpp
@@ -1611,16 +1611,26 @@ unsigned hash(
    switch(len)              /* all the case statements fall through */
    {
        case 11: c+=((unsigned)k[10] << 24);
+                FALLTHROUGH;
        case 10: c+=((unsigned)k[9] << 16);
+                FALLTHROUGH;
        case 9 : c+=((unsigned)k[8] << 8);
+                FALLTHROUGH;
           /* the first byte of c is reserved for the length */
        case 8 : b+=((unsigned)k[7] << 24);
+                FALLTHROUGH;
        case 7 : b+=((unsigned)k[6] << 16);
+                FALLTHROUGH;
        case 6 : b+=((unsigned)k[5] << 8);
+                FALLTHROUGH;
        case 5 : b+=k[4];
+                FALLTHROUGH;
        case 4 : a+=((unsigned)k[3] << 24);
+                FALLTHROUGH;
        case 3 : a+=((unsigned)k[2] << 16);
+                FALLTHROUGH;
        case 2 : a+=((unsigned)k[1] << 8);
+                FALLTHROUGH;
        case 1 : a+=k[0];
      /* case 0: nothing left to add */
    }

diff --git a/src/coreclr/src/ilasm/assembler.cpp b/src/coreclr/src/ilasm/assembler.cpp
@@ -1578,6 +1578,7 @@ void Assembler::EmitInstrVarByName(Instr* instr, __in __nullterminated char* lab
         case CEE_STARG:
         case CEE_STARG_S:
             nArgVarFlag++;
+            FALLTHROUGH;
         case CEE_LDLOCA:
         case CEE_LDLOCA_S:
         case CEE_LDLOC:

diff --git a/src/coreclr/src/ilasm/prebuilt/asmparse.cpp b/src/coreclr/src/ilasm/prebuilt/asmparse.cpp
@@ -2019,6 +2019,7 @@ YYLOCAL YYNEAR YYPASCAL YYPARSER()
 
 		yyerrlab:
 			++yynerrs;
+			FALLTHROUGH;
 
 		case 1:
 		case 2: /* incompletely recovered error ... try again */

diff --git a/src/coreclr/src/ildasm/dasm.cpp b/src/coreclr/src/ildasm/dasm.cpp
@@ -2008,6 +2008,7 @@ BYTE* PrettyPrintCABlobValue(PCCOR_SIGNATURE &typePtr,
                 break;
             case ELEMENT_TYPE_CLASS        :
                 typePtr += CorSigUncompressToken(typePtr, &tk); //skip the following token
+                FALLTHROUGH;
             case SERIALIZATION_TYPE_TYPE   :
                 appendStr(out,KEYWORD("type"));
                 appendStr(out,appendix);
@@ -2668,6 +2669,7 @@ void DumpDefaultValue(mdToken tok, __inout __nullterminated char* szString, void
                 break;
             }
             //else fall thru to default case, to report the error
+            FALLTHROUGH;
 
         default:
             szptr+=sprintf_s(szptr,SZSTRING_REMAINING_SIZE(szptr),ERRORMSG(" /* ILLEGAL CONSTANT type:0x%02X, size:%d bytes, blob: "),MDDV.m_bType,MDDV.m_cbSize);

diff --git a/src/coreclr/src/ildasm/dasm_sz.cpp b/src/coreclr/src/ildasm/dasm_sz.cpp
@@ -211,6 +211,7 @@ unsigned SizeOfField(PCCOR_SIGNATURE *ppSig, ULONG cSig, IMDInternalImport* pImp
                     case ELEMENT_TYPE_CMOD_OPT  :
                     case ELEMENT_TYPE_CMOD_REQD :
                         *ppSig += CorSigUncompressToken(*ppSig, &tk);
+                        FALLTHROUGH;
                     case ELEMENT_TYPE_PINNED    :
                     case ELEMENT_TYPE_SZARRAY    : // uElementNumber doesn't change
                         if(*ppSig < pSigEnd) Reiterate = TRUE;

diff --git a/src/coreclr/src/inc/palclr_win.h b/src/coreclr/src/inc/palclr_win.h
@@ -140,4 +140,8 @@
 typedef HMODULE NATIVE_LIBRARY_HANDLE;
 #endif // HOST_WINDOWS
 
+#ifndef FALLTHROUGH
+#define FALLTHROUGH __fallthrough
+#endif // FALLTHROUGH
+
 #endif	// __PALCLR_WIN_H__
diff --git a/src/coreclr/src/jit/assertionprop.cpp b/src/coreclr/src/jit/assertionprop.cpp
@@ -4546,7 +4546,7 @@ void Compiler::optImpliedByCopyAssertion(AssertionDsc* copyAssertion, AssertionD
                 // This is the ngen case where we have an indirection of an address.
                 noway_assert((impAssertion->op1.kind == O1K_EXACT_TYPE) || (impAssertion->op1.kind == O1K_SUBTYPE));
 
-                __fallthrough;
+                FALLTHROUGH;
 
             case O2K_CONST_INT:
                 usable = op1MatchesCopy && (impAssertion->op2.u1.iconVal == depAssertion->op2.u1.iconVal);

diff --git a/src/coreclr/src/jit/codegenarmarch.cpp b/src/coreclr/src/jit/codegenarmarch.cpp
@@ -207,7 +207,7 @@ void CodeGen::genCodeForTreeNode(GenTree* treeNode)
         case GT_AND:
             assert(varTypeIsIntegralOrI(treeNode));
 
-            __fallthrough;
+            FALLTHROUGH;
 
 #if !defined(TARGET_64BIT)
         case GT_ADD_LO:

diff --git a/src/coreclr/src/jit/codegencommon.cpp b/src/coreclr/src/jit/codegencommon.cpp
@@ -1421,7 +1421,7 @@ bool CodeGen::genCreateAddrMode(GenTree*  addr,
                         return false; // Need overflow check
                     }
 
-                    __fallthrough;
+                    FALLTHROUGH;
 
                 case GT_LSH:
 
@@ -1486,7 +1486,7 @@ bool CodeGen::genCreateAddrMode(GenTree*  addr,
                 break;
             }
 
-            __fallthrough;
+            FALLTHROUGH;
 
         case GT_LSH:
 
@@ -1568,7 +1568,7 @@ bool CodeGen::genCreateAddrMode(GenTree*  addr,
                 break;
             }
 
-            __fallthrough;
+            FALLTHROUGH;
 
         case GT_LSH:
 
@@ -8401,7 +8401,7 @@ void CodeGen::genFnEpilog(BasicBlock* block)
 
                     // otherwise the target address doesn't fit in an immediate
                     // so we have to burn a register...
-                    __fallthrough;
+                    FALLTHROUGH;
 
                 case IAT_PVALUE:
                     // Load the address into a register, load indirect and call  through a register

diff --git a/src/coreclr/src/jit/codegenlinear.cpp b/src/coreclr/src/jit/codegenlinear.cpp
@@ -720,7 +720,7 @@ void CodeGen::genCodeForBBlist()
 
             case BBJ_EHCATCHRET:
                 genEHCatchRet(block);
-                __fallthrough;
+                FALLTHROUGH;
 
             case BBJ_EHFINALLYRET:
             case BBJ_EHFILTERRET:
@@ -731,6 +731,7 @@ void CodeGen::genCodeForBBlist()
 
             case BBJ_EHCATCHRET:
                 noway_assert(!"Unexpected BBJ_EHCATCHRET"); // not used on x86
+                break;
 
             case BBJ_EHFINALLYRET:
             case BBJ_EHFILTERRET:

diff --git a/src/coreclr/src/jit/codegenxarch.cpp b/src/coreclr/src/jit/codegenxarch.cpp
@@ -1481,7 +1481,7 @@ void CodeGen::genCodeForTreeNode(GenTree* treeNode)
 #ifdef TARGET_X86
             assert(!treeNode->IsIconHandle(GTF_ICON_TLS_HDL));
 #endif // TARGET_X86
-            __fallthrough;
+            FALLTHROUGH;
 
         case GT_CNS_DBL:
             genSetRegToConst(targetReg, targetType, treeNode);
@@ -1504,7 +1504,7 @@ void CodeGen::genCodeForTreeNode(GenTree* treeNode)
                 genCodeForBinary(treeNode->AsOp());
                 break;
             }
-            __fallthrough;
+            FALLTHROUGH;
         case GT_MOD:
         case GT_UMOD:
         case GT_UDIV:
@@ -1516,7 +1516,7 @@ void CodeGen::genCodeForTreeNode(GenTree* treeNode)
         case GT_AND:
             assert(varTypeIsIntegralOrI(treeNode));
 
-            __fallthrough;
+            FALLTHROUGH;
 
 #if !defined(TARGET_64BIT)
         case GT_ADD_LO:

diff --git a/src/coreclr/src/jit/compiler.cpp b/src/coreclr/src/jit/compiler.cpp
@@ -8745,7 +8745,7 @@ void cTreeFlags(Compiler* comp, GenTree* tree)
                 {
                     chars += printf("[INX_STRING_LAYOUT]");
                 }
-                __fallthrough;
+                FALLTHROUGH;
             case GT_INDEX_ADDR:
                 if (tree->gtFlags & GTF_INX_RNGCHK)
                 {
@@ -8963,7 +8963,7 @@ void cTreeFlags(Compiler* comp, GenTree* tree)
                 {
                     chars += printf("[BLK_HASGCPTR]");
                 }
-                __fallthrough;
+                FALLTHROUGH;
 
             case GT_BLK:
             case GT_DYN_BLK:

diff --git a/src/coreclr/src/jit/compiler.h b/src/coreclr/src/jit/compiler.h
@@ -10349,7 +10349,7 @@ class GenTreeVisitor
                         return result;
                     }
                 }
-                __fallthrough;
+                FALLTHROUGH;
 
             // Leaf nodes
             case GT_CATCH_ARG:
@@ -10394,7 +10394,7 @@ class GenTreeVisitor
                         return result;
                     }
                 }
-                __fallthrough;
+                FALLTHROUGH;
 
             // Standard unary operators
             case GT_NOT:

diff --git a/src/coreclr/src/jit/compiler.hpp b/src/coreclr/src/jit/compiler.hpp
@@ -4347,7 +4347,7 @@ void GenTree::VisitOperands(TVisitor visitor)
             {
                 return;
             }
-            __fallthrough;
+            FALLTHROUGH;
 
         // Standard unary operators
         case GT_STORE_LCL_VAR:

diff --git a/src/coreclr/src/jit/disasm.cpp b/src/coreclr/src/jit/disasm.cpp
@@ -964,7 +964,7 @@ size_t DisAssembler::CbDisassemble(DIS*        pdis,
                 }
             }
 
-                __fallthrough;
+                FALLTHROUGH;
 
             case DISX86::trmtaJmpShort:
             case DISX86::trmtaJmpNear:
@@ -1022,7 +1022,7 @@ size_t DisAssembler::CbDisassemble(DIS*        pdis,
                 }
             }
 
-                __fallthrough;
+                FALLTHROUGH;
 
             case DISARM64::TRMTA::trmtaBra:
             case DISARM64::TRMTA::trmtaBraCase:

diff --git a/src/coreclr/src/jit/eeinterface.cpp b/src/coreclr/src/jit/eeinterface.cpp
@@ -142,7 +142,7 @@ const char* Compiler::eeGetMethodFullName(CORINFO_METHOD_HANDLE hnd)
                         }
                     }
                 }
-                    __fallthrough;
+                    FALLTHROUGH;
                 default:
                     pParam->pArgNames[i] = varTypeName(type);
                     break;
@@ -177,7 +177,7 @@ const char* Compiler::eeGetMethodFullName(CORINFO_METHOD_HANDLE hnd)
                         }
                     }
                 }
-                    __fallthrough;
+                    FALLTHROUGH;
                 default:
                     pParam->returnType = varTypeName(retType);
                     break;
-Original file line number
+Diff line change
@@ Expand Up / @@ -893,6 +893,7 @@ void DumpILToConsoleBare(unsigned char* ilCode, int len) @@
                             LogError("unknown ilCode 0xfe%2x at offset %d in MethodGen::PrettyPrint", ilCode[i], i);
                             break;
                     }
+                    break;
                 default:
                     LogError("unknown ilCode 0x%02x at offset %d in MethodGen::PrettyPrint", ilCode[i], i);
                     break;
@@ Expand Down @@