[WebAssembly] Add Emscripten OS definition + small_printf

The Emscripten OS provides a definition of __EMSCRIPTEN__, and also that it
supports iprintf optimizations.

Also define small_printf optimizations, which is a printf with float support
but not long double (which in wasm can be useful since long doubles are 128
bit and force linking of float128 emulation code). This part is based on
sunfish's https://reviews.llvm.org/D57620 (which can't land yet since
the WASI integration isn't ready yet).

Differential Revision: https://reviews.llvm.org/D60167

llvm-svn: 357552

1 files changed, 48 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 3920736a8d5..0af79f4b236 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -104,6 +104,12 @@ static bool callHasFloatingPointArgument(const CallInst *CI) {
   });
 }
 
+static bool callHasFP128Argument(const CallInst *CI) {
+  return any_of(CI->operands(), [](const Use &OI) {
+    return OI->getType()->isFP128Ty();
+  });
+}
+
 static Value *convertStrToNumber(CallInst *CI, StringRef &Str, int64_t Base) {
   if (Base < 2 || Base > 36)
     // handle special zero base
@@ -2051,6 +2057,20 @@ Value *LibCallSimplifier::optimizePrintF(CallInst *CI, IRBuilder<> &B) {
     B.Insert(New);
     return New;
   }
+
+  // printf(format, ...) -> __small_printf(format, ...) if no 128-bit floating point
+  // arguments.
+  if (TLI->has(LibFunc_small_printf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_printf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }
 
@@ -2131,6 +2151,20 @@ Value *LibCallSimplifier::optimizeSPrintF(CallInst *CI, IRBuilder<> &B) {
     B.Insert(New);
     return New;
   }
+
+  // sprintf(str, format, ...) -> __small_sprintf(str, format, ...) if no 128-bit
+  // floating point arguments.
+  if (TLI->has(LibFunc_small_sprintf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallSPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_sprintf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallSPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }
 
@@ -2288,6 +2322,20 @@ Value *LibCallSimplifier::optimizeFPrintF(CallInst *CI, IRBuilder<> &B) {
     B.Insert(New);
     return New;
   }
+
+  // fprintf(stream, format, ...) -> __small_fprintf(stream, format, ...) if no
+  // 128-bit floating point arguments.
+  if (TLI->has(LibFunc_small_fprintf) && !callHasFP128Argument(CI)) {
+    Module *M = B.GetInsertBlock()->getParent()->getParent();
+    auto SmallFPrintFFn =
+        M->getOrInsertFunction(TLI->getName(LibFunc_small_fprintf),
+                               FT, Callee->getAttributes());
+    CallInst *New = cast<CallInst>(CI->clone());
+    New->setCalledFunction(SmallFPrintFFn);
+    B.Insert(New);
+    return New;
+  }
+
   return nullptr;
 }