emit int32 for each version part

[lxfind]

Summary

The Version struct is defined with 4 int values. There is no reason we shouldn't use emitInt32 here. This gives more flexibility (e.g. if you use an internal sub-version that happens to be big)

[amccarth]

If you make the second loop consistent, I'll approve, despite my concerns about the related problems.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

793–794

On Windows (where CodeViewDebug is most important), version numbers are typically four 16-bit ints (packed into two 32-bit unsigned ints), but I guess there's no harm using 32-bit signed ints for a comment.

I'd suggest using a range-based for loop so we don't need to propagate the magic number 4.

801

If this output were to be processed by Windows tools expecting only 16 bits per version number component, this could overflow as soon at version 33 (or 66 is they really use unsigned 16-bit ints), and we're currently at 12. I see that this clamps to a 16-bit unsigned int. Maybe the Version struct should just be four of those.

806–807

Should this be emitInt32 as well? And again I'd use a range-based for loop.

[lxfind]

Address comments

[wenlei]

Looks like some CV/COFF tests need to be updated too?

[lxfind]

After some thought, I think this is not a good change. Many part of the system/toolchain expects each part to be 16-bit.

llvm/lib/CodeGen/AsmPrinter/CodeViewDebug.cpp

void CodeViewDebug::emitCompilerInformation() {
   OS.emitInt32(Flags);
 
   OS.AddComment("CPUType");
   OS.emitInt16(static_cast<uint64_t>(TheCPU));
 
   StringRef CompilerVersion = CU->getProducer();
   Version FrontVer = parseVersion(CompilerVersion);
   OS.AddComment("Frontend version");
-  for (int N = 0; N < 4; ++N)
-    OS.emitInt16(FrontVer.Part[N]);
+  for (int Part : FrontVer.Part)
+    OS.emitInt32(Part);
 
   // Some Microsoft tools, like Binscope, expect a backend version number of at
   // least 8.something, so we'll coerce the LLVM version into a form that
   // guarantees it'll be big enough without really lying about the version.
   int Major = 1000 * LLVM_VERSION_MAJOR +
               10 * LLVM_VERSION_MINOR +
               LLVM_VERSION_PATCH;
   // Clamp it for builds that use unusually large version numbers.
   Major = std::min<int>(Major, std::numeric_limits<uint16_t>::max());
   Version BackVer = {{ Major, 0, 0, 0 }};
   OS.AddComment("Backend version");
-  for (int N = 0; N < 4; ++N)
-    OS.emitInt16(BackVer.Part[N]);
+  for (int Part : BackVer.Part)
+    OS.emitInt32(Part);
 
   OS.AddComment("Null-terminated compiler version string");
   emitNullTerminatedSymbolName(OS, CompilerVersion);
 
   endSymbolRecord(CompilerEnd);
 }
 
 static TypeIndex getStringIdTypeIdx(GlobalTypeTableBuilder &TypeTable,