Use stringstream with locale override.

Add test for compiling float literals in locales with comma decimal separators.

Handle inexplicable test setlocale failure on Android,Linux. (Require success on other platforms)

Skip setting the locale on Android, which is always C locale in C++, but for some
reason std::locale::classic isn't implemented as a no-op.

Bug: angleproject:2607
Test: angle_unittests
Change-Id: I7c97cb56c01335db46f532fb8af3f9a4f2a30564

src/compiler/preprocessor/numeric_lex.h

@@ -48,10 +48,17 @@ bool numeric_lex_int(const std::string &str, IntType *value)
 template <typename FloatType>
 bool numeric_lex_float(const std::string &str, FloatType *value)
 {
-    // Some platforms have issues with the usage of std::locale and std::stringstream and cause
-    // crashes. Usage of strtod appears to be safe.
-    *value = static_cast<FloatType>(strtod(str.c_str(), nullptr));
-    return errno != ERANGE && std::isfinite(*value);
+    std::istringstream stream(str);
+
+// Android NDK forbids access to locales by always throwing instead of only accepting the C locale.
+#if !defined(ANGLE_PLATFORM_ANDROID)
+    // Force "C" locale so that decimal character is always '.', and not dependent on the current
+    // locale.
+    stream.imbue(std::locale::classic());
+#endif
+
+    stream >> (*value);
+    return !stream.fail() && std::isfinite(*value);
 }
 
 }  // namespace pp.

src/tests/compiler_tests/ShCompile_test.cpp

@@ -7,9 +7,11 @@
 //   Test the sh::Compile interface with different parameters.
 //
 
+#include <clocale>
+#include "GLSLANG/ShaderLang.h"
 #include "angle_gl.h"
+#include "common/platform.h"
 #include "gtest/gtest.h"
-#include "GLSLANG/ShaderLang.h"
 
 class ShCompileTest : public testing::Test
 {
@@ -36,13 +38,16 @@ class ShCompileTest : public testing::Test
 
     void testCompile(const char **shaderStrings, int stringCount, bool expectation)
     {
-        bool success                  = sh::Compile(mCompiler, shaderStrings, stringCount, 0);
+        ShCompileOptions options      = SH_OBJECT_CODE;
+        bool success                  = sh::Compile(mCompiler, shaderStrings, stringCount, options);
         const std::string &compileLog = sh::GetInfoLog(mCompiler);
         EXPECT_EQ(expectation, success) << compileLog;
     }
 
   private:
     ShBuiltInResources mResources;
+
+  public:
     ShHandle mCompiler;
 };
 
@@ -81,3 +86,41 @@ TEST_F(ShCompileTest, TokensSplitInShaderStrings)
 
     testCompile(shaderStrings, 3, true);
 }
+
+// Parsing floats in shaders can run afoul of locale settings.
+// In de_DE, `strtof("1.9")` will yield `1.0f`. (It's expecting "1,9")
+TEST_F(ShCompileTest, DecimalSepLocale)
+{
+    const auto defaultLocale = setlocale(LC_NUMERIC, nullptr);
+
+    const auto fnSetLocale = [](const char *const name) {
+        return bool(setlocale(LC_NUMERIC, name));
+    };
+
+    const bool setLocaleToDe =
+        fnSetLocale("de_DE") || fnSetLocale("de-DE");  // Windows doesn't like de_DE.
+
+// These configs don't support de_DE: android_angle_vk[32,64]_rel_ng, linux_angle_rel_ng
+// Just allow those platforms to quietly fail, but require other platforms to succeed.
+#if defined(ANGLE_PLATFORM_ANDROID) || defined(ANGLE_PLATFORM_LINUX)
+    if (!setLocaleToDe)
+    {
+        return;
+    }
+#endif
+    ASSERT_TRUE(setLocaleToDe);
+
+    const char kSource[] = R"(
+        void main()
+        {
+            gl_FragColor = vec4(1.9);
+        })";
+    const char *parts[] = {kSource};
+    testCompile(parts, 1, true);
+
+    const auto &translated = sh::GetObjectCode(mCompiler);
+    // printf("%s\n", translated.data());
+    EXPECT_NE(translated.find("1.9"), std::string::npos);
+
+    fnSetLocale(defaultLocale);
+}