[support] Support printing floats in ScopedPrinter

[paulkirth]

Summary

llvm-readobj will need the ability to print floats for use in
HashHistograms. This adds that functionality to the ScopedPrinter and
JSONScopedPrinter.

[paulkirth]

Rebase.

[paulkirth]

Rebase.

[paulkirth]

Fix formatting

[jhenderson]

llvm/include/llvm/Support/ScopedPrinter.h

237

Would it make sense to add a double overload too, whilst you're at it? I think it might be a little confusing having one but not the other. (I can see the argument against it, since it's not going to be used immediately though, so happy either way)

llvm/unittests/Support/ScopedPrinterTest.cpp

560

Perhaps should check infinity too (https://en.cppreference.com/w/cpp/types/numeric_limits/infinity).

[paulkirth]

llvm/include/llvm/Support/ScopedPrinter.h

237

I think that is a good idea, and is probably more consistent w/ JSON representation anyway.

llvm/unittests/Support/ScopedPrinterTest.cpp

560

Good catch. Thank you.

[paulkirth]

Address comments.

• add overloads for double
• add test w/ infinity

[jhenderson]

Looks good, but see inline comment for possible suggestion.

llvm/unittests/Support/ScopedPrinterTest.cpp

592

Just a thought, but this value is implementation defined ultimately. I'm not suggesting necessarily changing this, but if you don't, you should keep a close eye on CI after landing this in case it doesn't work for a particularly system.

The alternative would be to build this string up dynamically, using std::to_string on the same values as the ones passed to printNumber.

[paulkirth]

Update test to avoid implementation specific output.

[abhina.sreeskantharajan]

Hi, I think this patch is causing a failure on the clang-ppc64-aix bot here https://lab.llvm.org/buildbot/#/builders/214/builds/6531/steps/6/logs/FAIL__LLVM-Unit__83 . Would you be able to take a look?

[paulkirth]

Sorry for the trouble. looking now

[paulkirth]

so it looks like there are additional platform specific behaviors to how things like infinite are printed (inf vs INF, etc.). @abhina.sreeskantharajan I should be able to forward fix this fairly soon, probably in an hour(commute + meeting), but all that should be required is to adjust the test string the same way we do for max doubles/floats so that it's dynamically created and will thus match on all platforms.

[paulkirth]

fix up in D146542.

llvm/include/llvm/Support/ScopedPrinter.h

public:
   virtual void printNumber(StringRef Label, int8_t Value) {
     startLine() << Label << ": " << int(Value) << "\n";
   }
 
   virtual void printNumber(StringRef Label, const APSInt &Value) {
     startLine() << Label << ": " << Value << "\n";
   }
 
+  virtual void printNumber(StringRef Label, float Value) {
+    startLine() << Label << ": " << format("%5.1f", Value) << "\n";
+  }
+
   template <typename T>
   void printNumber(StringRef Label, StringRef Str, T Value) {
     printNumberImpl(Label, Str, to_string(Value));
   }
 
   virtual void printBoolean(StringRef Label, bool Value) {
     startLine() << Label << ": " << (Value ? "Yes" : "No") << '\n';
   }
public:
   void printNumber(StringRef Label, int16_t Value) override {
     JOS.attribute(Label, Value);
   }
 
   void printNumber(StringRef Label, int8_t Value) override {
     JOS.attribute(Label, Value);
   }
 
+  void printNumber(StringRef Label, float Value) override {
+    JOS.attribute(Label, Value);
+  }
+
   void printNumber(StringRef Label, const APSInt &Value) override {
     JOS.attributeBegin(Label);
     printAPSInt(Value);
     JOS.attributeEnd();
   }
 
   void printBoolean(StringRef Label, bool Value) override {
     JOS.attribute(Label, Value);

llvm/unittests/Support/ScopedPrinterTest.cpp

 //===- llvm/unittest/Support/ScopedPrinterTest.cpp - ScopedPrinter tests --===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Support/ScopedPrinter.h"
 #include "llvm/ADT/APSInt.h"
 #include "gtest/gtest.h"
 #include <vector>
+#include <cmath>
 
 using namespace llvm;
 
 TEST(JSONScopedPrinterTest, PrettyPrintCtor) {
   auto PrintFunc = [](ScopedPrinter &W) {
     DictScope D(W);
     W.printString("Key", "Value");
   };
auto PrintFunc = [](ScopedPrinter &W) {
     int8_t Signed8Min = std::numeric_limits<int8_t>::min();
     W.printNumber("int8_t-max", Signed8Max);
     W.printNumber("int8_t-min", Signed8Min);
 
     APSInt LargeNum("9999999999999999999999");
     W.printNumber("apsint", LargeNum);
 
     W.printNumber("label", "value", 0);
+
+    float MaxFloat = std::numeric_limits<float>::max();
+    float MinFloat = std::numeric_limits<float>::min();
+    float NaN = std::nanf("1");
+    W.printNumber("float-max", MaxFloat);
+    W.printNumber("float-min", MinFloat);
+    W.printNumber("float-nan", NaN);
+    W.printNumber("float-42.0", 42.0f);
+    W.printNumber("float-42.5625", 42.5625f);
   };
 
   const char *ExpectedOut = R"(uint64_t-max: 18446744073709551615
 uint64_t-min: 0
 uint32_t-max: 4294967295
 uint32_t-min: 0
 uint16_t-max: 65535
 uint16_t-min: 0
 uint8_t-max: 255
 uint8_t-min: 0
 int64_t-max: 9223372036854775807
 int64_t-min: -9223372036854775808
 int32_t-max: 2147483647
 int32_t-min: -2147483648
 int16_t-max: 32767
 int16_t-min: -32768
 int8_t-max: 127
 int8_t-min: -128
 apsint: 9999999999999999999999
 label: value (0)
+float-max: 340282346638528859811704183484516925440.0
+float-min:   0.0
+float-nan:   nan
+float-42.0:  42.0
+float-42.5625:  42.6
 )";
 
   const char *JSONExpectedOut = R"({
   "uint64_t-max": 18446744073709551615,
   "uint64_t-min": 0,
   "uint32_t-max": 4294967295,
   "uint32_t-min": 0,
   "uint16_t-max": 65535,
   "uint16_t-min": 0,
   "uint8_t-max": 255,
   "uint8_t-min": 0,
   "int64_t-max": 9223372036854775807,
   "int64_t-min": -9223372036854775808,
   "int32_t-max": 2147483647,
   "int32_t-min": -2147483648,
   "int16_t-max": 32767,
   "int16_t-min": -32768,
   "int8_t-max": 127,
   "int8_t-min": -128,
   "apsint": 9999999999999999999999,
   "label": {
     "Name": "value",
     "Value": 0
-  }
+  },
+  "float-max": 3.4028234663852886e+38,
+  "float-min": 1.1754943508222875e-38,
+  "float-nan": nan,
+  "float-42.0": 42,
+  "float-42.5625": 42.5625
 })";
   verifyAll(ExpectedOut, JSONExpectedOut, PrintFunc);
 }
 
 TEST_F(ScopedPrinterTest, PrintBoolean) {
   auto PrintFunc = [](ScopedPrinter &W) {
     W.printBoolean("True", true);
     W.printBoolean("False", false);