Cleanup more GCC warnings (#22872)

* Add parenthesis

src/vm/sha1.cpp: In function ‘void SHA1_block(SHA1_CTX*)’:
src/vm/sha1.cpp:93:29: warning: suggest parentheses around arithmetic in operand of ‘|’ [-Wparentheses]
 #define ROUND3(B, C, D) ((C & (B | D) | (B & D)) + sha1_round3)
                             ^
src/vm/sha1.cpp:139:32: note: in expansion of macro ‘ROUND3’
         e += ROTATE32L(a, 5) + ROUND3(b, c, d) + msg80[i];

* Move declaration into same file as one was defined Extern the other one was static

* Remove hr=hr undefined assignment

* Fix mutli-line comment warning

* Convert multi-character literal

* Remove null check for stack local variables

rc/vm/invokeutil.cpp: In static member function ‘static void InvokeUtil::SetValidField(CorElementType, TypeHandle, FieldDesc*, OBJECTREF*, OBJECTREF*, TypeHandle, CLR_BOOL*)’:
src/vm/invokeutil.cpp:978:29: warning: the address of ‘Throwable’ will never be NULL [-Waddress]
EX_CATCH_THROWABLE(&Throwable);
^
src/inc/ex.h:1087:21: note: in definition of macro ‘EX_CATCH_THROWABLE’
if (NULL != ppThrowable)
^

7 files changed, 9 insertions, 13 deletions

diff --git a/src/ToolBox/SOS/Strike/sildasm.cpp b/src/ToolBox/SOS/Strike/sildasm.cpp
index 911ff091e5..097376d553 100644
--- a/src/ToolBox/SOS/Strike/sildasm.cpp
+++ b/src/ToolBox/SOS/Strike/sildasm.cpp
@@ -65,6 +65,7 @@ static OpCode opcodes[] =
 
 static ULONG position = 0;
 static BYTE *pBuffer = NULL;
+static char* asString(CQuickBytes *out);
 
 // The UNALIGNED is because on IA64 alignment rules would prevent
 // us from reading a pointer from an unaligned source.
diff --git a/src/ToolBox/SOS/Strike/sos_md.h b/src/ToolBox/SOS/Strike/sos_md.h
index b589109986..a7cd30c3bc 100644
--- a/src/ToolBox/SOS/Strike/sos_md.h
+++ b/src/ToolBox/SOS/Strike/sos_md.h
@@ -872,8 +872,6 @@ typedef enum
 }
 PPFormatFlags;
 
-char* asString(CQuickBytes *out);
-
 PCCOR_SIGNATURE PrettyPrintType(
     PCCOR_SIGNATURE typePtr,            // type to convert,     
     CQuickBytes *out,                   // where to put the pretty printed string   
diff --git a/src/classlibnative/bcltype/varargsnative.cpp b/src/classlibnative/bcltype/varargsnative.cpp
index 33dd816477..10354c6897 100644
--- a/src/classlibnative/bcltype/varargsnative.cpp
+++ b/src/classlibnative/bcltype/varargsnative.cpp
@@ -87,8 +87,8 @@ static void InitCommon(VARARGS *data, VASigCookie** cookie)
     //  STACK_GROWS_DOWN_ON_ARGS_WALK
 
     //   <return address>  ;; lower memory                  
-    //   <varargs_cookie>         \
-    //   <argN>                    \
+    //   <varargs_cookie>         '\'
+    //   <argN>                    '\'
     //                              += sizeOfArgs     
     //                             /
     //   <arg1>                   /
diff --git a/src/debug/di/module.cpp b/src/debug/di/module.cpp
index 5097008be0..1263e710e4 100644
--- a/src/debug/di/module.cpp
+++ b/src/debug/di/module.cpp
@@ -4988,7 +4988,7 @@ HRESULT CordbNativeCode::EnsureReturnValueAllowedWorker(Instantiation *currentIn
         IfFailRet(CordbType::SigToType(GetModule(), &original, &inst, &pType));
 
         
-        IfFailRet(hr = pType->ReturnedByValue());
+        IfFailRet(pType->ReturnedByValue());
         if (hr == S_OK) // not S_FALSE
             return S_OK;
 
@@ -5001,7 +5001,7 @@ HRESULT CordbNativeCode::EnsureReturnValueAllowedWorker(Instantiation *currentIn
         CordbType *pType = 0;
         IfFailRet(CordbType::SigToType(GetModule(), &original, &inst, &pType));
 
-        IfFailRet(hr = pType->ReturnedByValue());
+        IfFailRet(pType->ReturnedByValue());
         if (hr == S_OK) // not S_FALSE
             return S_OK;
 
diff --git a/src/inc/ex.h b/src/inc/ex.h
index 9cd2adbeaa..87d47c313d 100644
--- a/src/inc/ex.h
+++ b/src/inc/ex.h
@@ -1084,10 +1084,7 @@ Exception *ExThrowWithInnerHelper(Exception *inner);
 #define EX_CATCH_THROWABLE(ppThrowable)                                         \
     EX_CATCH                                                                    \
     {                                                                           \
-        if (NULL != ppThrowable)                                                \
-        {                                                                       \
-            *ppThrowable = GET_THROWABLE();                                     \
-        }                                                                       \
+        *ppThrowable = GET_THROWABLE();                                         \
     }                                                                           \
     EX_END_CATCH(SwallowAllExceptions)
 
diff --git a/src/vm/sha1.cpp b/src/vm/sha1.cpp
index 6d0784e89a..6ac8d46bd2 100644
--- a/src/vm/sha1.cpp
+++ b/src/vm/sha1.cpp
@@ -90,7 +90,7 @@ static void SHA1_block(SHA1_CTX *ctx)
                         //  (check cases B = 0 and B = 1)
 #define ROUND2(B, C, D) ((B ^ C ^ D) + sha1_round2)
 
-#define ROUND3(B, C, D) ((C & (B | D) | (B & D)) + sha1_round3)
+#define ROUND3(B, C, D) (((C & (B | D)) | (B & D)) + sha1_round3)
 
 #define ROUND4(B, C, D) ((B ^ C ^ D) + sha1_round4)
 
diff --git a/src/zap/zapimage.cpp b/src/zap/zapimage.cpp
index d5d48ae2d6..7a849fbfcc 100644
--- a/src/zap/zapimage.cpp
+++ b/src/zap/zapimage.cpp
@@ -1025,8 +1025,8 @@ HANDLE ZapImage::GenerateFile(LPCWSTR wszOutputFileName, CORCOMPILE_NGEN_SIGNATU
     {    
         // Write the debug directory entry for the NGEN PDB
         RSDS rsds = {0};
-        
-        rsds.magic = 'SDSR';
+
+        rsds.magic = VAL32(0x53445352); // "SDSR";
         rsds.age = 1;
         // our PDB signature will be the same as our NGEN signature.  
         // However we want the printed version of the GUID to be be the same as the