[WebAssembly] Replace varargs debugPrint with standard log call

[ncw]

Summary

varargs is less safe than llvm::formatv which uses a template, and the LLVM log call is more configurable than going directly to stderr in this place in LLD

wasm/Writer.cpp

private:
   std::unique_ptr<FileOutputBuffer> Buffer;
 
   std::vector<OutputSegment *> Segments;
   llvm::SmallDenseMap<StringRef, OutputSegment *> SegmentMap;
 };
 
 } // anonymous namespace
 
-static void debugPrint(const char *fmt, ...) {
-  if (!errorHandler().Verbose)
-    return;
-  fprintf(stderr, "lld: ");
-  va_list ap;
-  va_start(ap, fmt);
-  vfprintf(stderr, fmt, ap);
-  va_end(ap);
-}
-
 void Writer::createImportSection() {
   uint32_t NumImports = ImportedSymbols.size();
   if (Config->ImportMemory)
     ++NumImports;
 
   if (NumImports == 0)
     return;
 

 // The memory layout is as follows, from low to high.
 //  - initialized data (starting at Config->GlobalBase)
 //  - BSS data (not currently implemented in llvm)
 //  - explicit stack (Config->ZStackSize)
 //  - heap start / unallocated
 void Writer::layoutMemory() {
   uint32_t MemoryPtr = 0;
   MemoryPtr = Config->GlobalBase;
-  debugPrint("mem: global base = %d\n", Config->GlobalBase);
+  log("mem: global base = " + Twine(Config->GlobalBase));
 
   createOutputSegments();
 
   // Arbitrarily set __dso_handle handle to point to the start of the data
   // segments.
   if (WasmSym::DsoHandle)
     WasmSym::DsoHandle->setVirtualAddress(MemoryPtr);
 
   for (OutputSegment *Seg : Segments) {
     MemoryPtr = alignTo(MemoryPtr, Seg->Alignment);
     Seg->StartVA = MemoryPtr;
-    debugPrint("mem: %-15s offset=%-8d size=%-8d align=%d\n",
-               Seg->Name.str().c_str(), MemoryPtr, Seg->Size, Seg->Alignment);
+    log(formatv("mem: {0,-15} offset={1,-8} size={2,-8} align={3}", Seg->Name,
+                MemoryPtr, Seg->Size, Seg->Alignment));
     MemoryPtr += Seg->Size;
   }
 
   // TODO: Add .bss space here.
   if (WasmSym::DataEnd)
     WasmSym::DataEnd->setVirtualAddress(MemoryPtr);
 
-  debugPrint("mem: static data = %d\n", MemoryPtr - Config->GlobalBase);
+  log("mem: static data = " + Twine(MemoryPtr - Config->GlobalBase));
 
   // Stack comes after static data and bss
   if (!Config->Relocatable) {
     MemoryPtr = alignTo(MemoryPtr, kStackAlignment);
     if (Config->ZStackSize != alignTo(Config->ZStackSize, kStackAlignment))
       error("stack size must be " + Twine(kStackAlignment) + "-byte aligned");
-    debugPrint("mem: stack size  = %d\n", Config->ZStackSize);
-    debugPrint("mem: stack base  = %d\n", MemoryPtr);
+    log("mem: stack size  = " + Twine(Config->ZStackSize));
+    log("mem: stack base  = " + Twine(MemoryPtr));
     MemoryPtr += Config->ZStackSize;
     WasmSym::StackPointer->Global->Global.InitExpr.Value.Int32 = MemoryPtr;
-    debugPrint("mem: stack top   = %d\n", MemoryPtr);
+    log("mem: stack top   = " + Twine(MemoryPtr));
 
     // Set `__heap_base` to directly follow the end of the stack.  We don't
     // allocate any heap memory up front, but instead really on the malloc/brk
     // implementation growing the memory at runtime.
     WasmSym::HeapBase->setVirtualAddress(MemoryPtr);
-    debugPrint("mem: heap base   = %d\n", MemoryPtr);
+    log("mem: heap base   = " + Twine(MemoryPtr));
   }
 
   uint32_t MemSize = alignTo(MemoryPtr, WasmPageSize);
   NumMemoryPages = MemSize / WasmPageSize;
-  debugPrint("mem: total pages = %d\n", NumMemoryPages);
+  log("mem: total pages = " + Twine(NumMemoryPages));
 }
 
 SyntheticSection *Writer::createSyntheticSection(uint32_t Type,
                                                  StringRef Name) {
   auto Sec = make<SyntheticSection>(Type, Name);
   log("createSection: " + toString(*Sec));
   OutputSections.push_back(Sec);
   return Sec;