8345265: Minor improvements for LTO across all compilers

make/hotspot/lib/JvmFeatures.gmk

@@ -169,19 +169,19 @@ ifeq ($(call check-jvm-feature, link-time-opt), true)
   # Set JVM_OPTIMIZATION directly so other jvm-feature flags can override it
   # later on if desired
   JVM_OPTIMIZATION := HIGHEST_JVM
-  ifeq ($(call isCompiler, gcc), true)
-    JVM_CFLAGS_FEATURES += -flto=auto -fuse-linker-plugin -fno-strict-aliasing \
+  ifeq ($(TOOLCHAIN_TYPE), gcc)
+    JVM_CFLAGS_FEATURES += -flto=$(JOBS) -fuse-linker-plugin -fno-strict-aliasing \
         -fno-fat-lto-objects
-    JVM_LDFLAGS_FEATURES += $(CXX_O_FLAG_HIGHEST_JVM) -flto=auto \
-        -fuse-linker-plugin -fno-strict-aliasing
-  else ifeq ($(call isCompiler, clang), true)
+    JVM_LDFLAGS_FEATURES += $(CXX_O_FLAG_HIGHEST_JVM) -flto=$(JOBS) \
+        -fuse-linker-plugin -fno-strict-aliasing -fno-omit-frame-pointer -Wno-attribute-warning
+  else ifeq ($(TOOLCHAIN_TYPE), clang)
     JVM_CFLAGS_FEATURES += -flto -fno-strict-aliasing
-    ifeq ($(call isBuildOs, aix), true)
+    ifeq ($(call isTargetOs, aix), true)
       JVM_CFLAGS_FEATURES += -ffat-lto-objects
     endif
     JVM_LDFLAGS_FEATURES += $(CXX_O_FLAG_HIGHEST_JVM) -flto -fno-strict-aliasing
-  else ifeq ($(call isCompiler, microsoft), true)
-    JVM_CFLAGS_FEATURES += -GL
+  else ifeq ($(TOOLCHAIN_TYPE), microsoft)
+    JVM_CFLAGS_FEATURES += -GL -Gy
     JVM_LDFLAGS_FEATURES += -LTCG:INCREMENTAL
   endif
 else

make/hotspot/lib/JvmOverrideFiles.gmk

@@ -37,10 +37,6 @@ ifeq ($(TOOLCHAIN_TYPE), gcc)
     # Need extra inlining to collapse shared marking code into the hot marking loop
     BUILD_LIBJVM_shenandoahMark.cpp_CXXFLAGS := --param inline-unit-growth=1000
   endif
-  # disable lto in g1ParScanThreadState because of special inlining/flattening used there
-  ifeq ($(call check-jvm-feature, link-time-opt), true)
-    BUILD_LIBJVM_g1ParScanThreadState.cpp_CXXFLAGS := -fno-lto
-  endif
 endif
 
 LIBJVM_FDLIBM_COPY_OPT_FLAG := $(CXX_O_FLAG_NONE)