diff --git a/make/jprt.config b/make/jprt.config
index 2c1f0dce2f4e393c2d6dc2d0f93df38b2d8176d6..4964914e0628dfcf2da2a4c85d3f423eadb067d7 100644
--- a/make/jprt.config
+++ b/make/jprt.config
@@ -68,8 +68,23 @@ if [ "${osname}" = SunOS ] ; then
 	solaris_arch=i386
     fi
 
-    # Get the SS11 compilers into path (make sure it matches ALT setting)
-    compiler_path=${slashjava}/devtools/${solaris_arch}/SUNWspro/SS11/bin
+    if [ "${JPRT_SOLARIS_COMPILER_NAME}" != "" ] ; then
+        compiler_name=${JPRT_SOLARIS_COMPILER_NAME}
+    else
+        if [ "${JPRT_JOB_PRODUCT_RELEASE}" = "jdk6"      -o \
+             "${JPRT_JOB_PRODUCT_RELEASE}" = "jdk6u10"   -o \
+             "${JPRT_JOB_PRODUCT_RELEASE}" = "jdk6perf" ] ; then
+            # All jdk6 builds use SS11
+            compiler_name=SS11
+        else
+            # FIXUP: Change to SS12 once it has been validated.
+	    #compiler_name=SS12
+            compiler_name=SS11
+        fi
+    fi
+    
+    # Get into path (make sure it matches ALT setting)
+    compiler_path=${slashjava}/devtools/${solaris_arch}/SUNWspro/${compiler_name}/bin
     dirMustExist "${compiler_path}" COMPILER_PATH
     path4sdk=${compiler_path}
 
diff --git a/make/solaris/makefiles/debug.make b/make/solaris/makefiles/debug.make
index d759910be9e83335bc6840f5ca8fed7986345735..4474ec9d8e02bcaae4c8c2f979d854d318fcd77d 100644
--- a/make/solaris/makefiles/debug.make
+++ b/make/solaris/makefiles/debug.make
@@ -29,7 +29,8 @@ DEBUG_CFLAGS/DEFAULT= $(DEBUG_CFLAGS)
 DEBUG_CFLAGS/BYFILE = $(DEBUG_CFLAGS/$@)$(DEBUG_CFLAGS/DEFAULT$(DEBUG_CFLAGS/$@))
 
 ifeq ("${Platform_compiler}", "sparcWorks")
-ifeq ($(shell expr $(COMPILER_REV) \>= 5.8), 1)
+
+ifeq ($(COMPILER_REV),5.8)
   # SS11 SEGV when compiling with -g and -xarch=v8, using different backend
   DEBUG_CFLAGS/compileBroker.o = $(DEBUG_CFLAGS) -xO0
   DEBUG_CFLAGS/jvmtiTagMap.o   = $(DEBUG_CFLAGS) -xO0
diff --git a/make/solaris/makefiles/dtrace.make b/make/solaris/makefiles/dtrace.make
index f4f7edf934d1da135345238fa68b0d5533a9bfdb..0d3dce0fcceb0b31deea5e6e3b60c5c745e867e9 100644
--- a/make/solaris/makefiles/dtrace.make
+++ b/make/solaris/makefiles/dtrace.make
@@ -92,12 +92,12 @@ XARCH = $(subst sparcv9,v9,$(shell echo $(ISA)))
 $(XLIBJVM_DB): $(DTRACE_SRCDIR)/$(JVM_DB).c $(JVMOFFS).h $(LIBJVM_DB_MAPFILE)
 	@echo Making $@
 	$(QUIETLY) mkdir -p 64/ ; \
-	$(CC) $(SYMFLAG) -xarch=$(XARCH) -D$(TYPE) -I. -I$(GENERATED) \
+	$(CC) $(SYMFLAG) $(ARCHFLAG/$(XARCH)) -D$(TYPE) -I. -I$(GENERATED) \
 		$(SHARED_FLAG) $(LFLAGS_JVM_DB) -o $@ $(DTRACE_SRCDIR)/$(JVM_DB).c -lc
 $(XLIBJVM_DTRACE): $(DTRACE_SRCDIR)/$(JVM_DTRACE).c $(DTRACE_SRCDIR)/$(JVM_DTRACE).h $(LIBJVM_DTRACE_MAPFILE)
 	@echo Making $@
 	$(QUIETLY) mkdir -p 64/ ; \
-	$(CC) $(SYMFLAG) -xarch=$(XARCH) -D$(TYPE) -I. \
+	$(CC) $(SYMFLAG) $(ARCHFLAG/$(XARCH)) -D$(TYPE) -I. \
 		$(SHARED_FLAG) $(LFLAGS_JVM_DTRACE) -o $@ $(DTRACE_SRCDIR)/$(JVM_DTRACE).c -lc -lthread -ldoor
 endif # ifneq ("${ISA}","${BUILDARCH}")
 
diff --git a/make/solaris/makefiles/fastdebug.make b/make/solaris/makefiles/fastdebug.make
index 0329b4c36783168994fa21419e780aebc4f47fff..4c5a4eee84781361572c80252a1b78da47d1980b 100644
--- a/make/solaris/makefiles/fastdebug.make
+++ b/make/solaris/makefiles/fastdebug.make
@@ -25,7 +25,7 @@
 # Sets make macros for making debug version of VM
 
 # Compiler specific DEBUG_CFLAGS are passed in from gcc.make, sparcWorks.make
-# They may also specify FASTDEBUG_CFLAGS, but it defaults to DEBUG_FLAGS.
+# They may also specify FASTDEBUG_CFLAGS, but it defaults to DEBUG_CFLAGS.
 
 FASTDEBUG_CFLAGS$(FASTDEBUG_CFLAGS) = $(DEBUG_CFLAGS)
 
@@ -35,15 +35,26 @@ OPT_CFLAGS/BYFILE = $(OPT_CFLAGS/$@)$(OPT_CFLAGS/DEFAULT$(OPT_CFLAGS/$@))
 
 ifeq ("${Platform_compiler}", "sparcWorks")
 OPT_CFLAGS/SLOWER = -xO2
-ifeq ($(shell expr $(COMPILER_REV) \>= 5.5), 1)
-# CC 5.5 has bug 4908364 with -xO4 
+
+# Problem with SS12 compiler, dtrace doesn't like the .o files  (bug 6693876)
+ifeq ($(COMPILER_REV), 5.9)
+  # Not clear this workaround could be skipped in some cases.
+  OPT_CFLAGS/vmGCOperations.o = $(OPT_CFLAGS/SLOWER)
+  OPT_CFLAGS/java.o = $(OPT_CFLAGS/SLOWER)
+  OPT_CFLAGS/jni.o = $(OPT_CFLAGS/SLOWER)
+endif
+
+ifeq ($(COMPILER_REV), 5.5)
+# CC 5.5 has bug 4908364 with -xO4  (Fixed in 5.6)
 OPT_CFLAGS/library_call.o = $(OPT_CFLAGS/SLOWER)
-else # COMPILER_REV >= 5.5
+endif # COMPILER_REV == 5.5
+
+ifeq ($(shell expr $(COMPILER_REV) \<= 5.4), 1)
 # Compilation of *_<arch>.cpp can take an hour or more at O3.  Use O2
 # See comments at top of sparc.make.
 OPT_CFLAGS/ad_$(Platform_arch).o = $(OPT_CFLAGS/SLOWER)
 OPT_CFLAGS/dfa_$(Platform_arch).o = $(OPT_CFLAGS/SLOWER)
-endif # COMPILER_REV >= 5.5
+endif # COMPILER_REV <= 5.4
 
 ifeq (${COMPILER_REV}, 5.0)
 # Avoid a compiler bug caused by using -xO<level> -g<level>
diff --git a/make/solaris/makefiles/jvmg.make b/make/solaris/makefiles/jvmg.make
index 24a3510d4a50810c905d196b4f50685c75726dfa..3233025b031d84f05014c94add06108638272e25 100644
--- a/make/solaris/makefiles/jvmg.make
+++ b/make/solaris/makefiles/jvmg.make
@@ -29,7 +29,8 @@ DEBUG_CFLAGS/DEFAULT= $(DEBUG_CFLAGS)
 DEBUG_CFLAGS/BYFILE = $(DEBUG_CFLAGS/$@)$(DEBUG_CFLAGS/DEFAULT$(DEBUG_CFLAGS/$@))
 
 ifeq ("${Platform_compiler}", "sparcWorks")
-ifeq ($(shell expr $(COMPILER_REV) \>= 5.8), 1)
+
+ifeq ($(COMPILER_REV),5.8))
   # SS11 SEGV when compiling with -g and -xarch=v8, using different backend
   DEBUG_CFLAGS/compileBroker.o = $(DEBUG_CFLAGS) -xO0
   DEBUG_CFLAGS/jvmtiTagMap.o   = $(DEBUG_CFLAGS) -xO0
diff --git a/make/solaris/makefiles/optimized.make b/make/solaris/makefiles/optimized.make
index 4e8f6484790395f51ee37e677f60530a4d16647a..ed3d8e02c7e09b16fe99999bf19ddd47731b58bb 100644
--- a/make/solaris/makefiles/optimized.make
+++ b/make/solaris/makefiles/optimized.make
@@ -30,12 +30,21 @@ OPT_CFLAGS/DEFAULT= $(OPT_CFLAGS)
 OPT_CFLAGS/BYFILE = $(OPT_CFLAGS/$@)$(OPT_CFLAGS/DEFAULT$(OPT_CFLAGS/$@))
 
 # (OPT_CFLAGS/SLOWER is also available, to alter compilation of buggy files)
-
-# Workaround SS11 bug 6345274 (all platforms)
 ifeq ("${Platform_compiler}", "sparcWorks")
-ifeq ($(shell expr $(COMPILER_REV) \>= 5.8), 1)
+
+# Problem with SS12 compiler, dtrace doesn't like the .o files  (bug 6693876)
+ifeq ($(COMPILER_REV),5.9)
+  # Not clear this workaround could be skipped in some cases.
+  OPT_CFLAGS/vmGCOperations.o = $(OPT_CFLAGS/SLOWER) -g
+  OPT_CFLAGS/java.o = $(OPT_CFLAGS/SLOWER) -g
+  OPT_CFLAGS/jni.o = $(OPT_CFLAGS/SLOWER) -g
+endif
+
+# Workaround SS11 bug 6345274 (all platforms) (Fixed in SS11 patch and SS12)
+ifeq ($(COMPILER_REV),5.8))
 OPT_CFLAGS/ciTypeFlow.o = $(OPT_CFLAGS/O2)
-endif # COMPILER_REV >= 5.8
+endif # COMPILER_REV == 5.8
+
 endif # Platform_compiler == sparcWorks
 
 # If you set HOTSPARC_GENERIC=yes, you disable all OPT_CFLAGS settings
diff --git a/make/solaris/makefiles/product.make b/make/solaris/makefiles/product.make
index d2e78c6646a5a7ebf4d1db9dc79380ce1144a085..da8bab3da293a3b1faeffa62bb9013dac01abac7 100644
--- a/make/solaris/makefiles/product.make
+++ b/make/solaris/makefiles/product.make
@@ -38,12 +38,21 @@ OPT_CFLAGS/ciEnv.o = $(OPT_CFLAGS) -xinline=no%__1cFciEnvbFpost_compiled_method_
 endif
 
 # (OPT_CFLAGS/SLOWER is also available, to alter compilation of buggy files)
-
-# Workaround SS11 bug 6345274 (all platforms)
 ifeq ("${Platform_compiler}", "sparcWorks")
-ifeq ($(shell expr $(COMPILER_REV) \>= 5.8), 1)
+
+# Problem with SS12 compiler, dtrace doesn't like the .o files  (bug 6693876)
+ifeq ($(COMPILER_REV),5.9)
+  # Not clear this workaround could be skipped in some cases.
+  OPT_CFLAGS/vmGCOperations.o = $(OPT_CFLAGS/SLOWER) -g
+  OPT_CFLAGS/java.o = $(OPT_CFLAGS/SLOWER) -g
+  OPT_CFLAGS/jni.o = $(OPT_CFLAGS/SLOWER) -g
+endif
+
+# Workaround SS11 bug 6345274 (all platforms) (Fixed in SS11 patch and SS12)
+ifeq ($(COMPILER_REV),5.8)
 OPT_CFLAGS/ciTypeFlow.o = $(OPT_CFLAGS/O2)
-endif # COMPILER_REV >= 5.8
+endif # COMPILER_REV == 5.8
+
 endif # Platform_compiler == sparcWorks
 
 # If you set HOTSPARC_GENERIC=yes, you disable all OPT_CFLAGS settings
diff --git a/make/solaris/makefiles/sparc.make b/make/solaris/makefiles/sparc.make
index b3a0e2682bbded2ddced6cf89616960afd619064..46ce5ce79b92c9b146cde2633de08be9dfab1169 100644
--- a/make/solaris/makefiles/sparc.make
+++ b/make/solaris/makefiles/sparc.make
@@ -23,7 +23,7 @@
 #
 
 Obj_Files += solaris_sparc.o
-ASFLAGS += $(ARCHFLAG)
+ASFLAGS += $(AS_ARCHFLAG)
 
 ifeq ("${Platform_compiler}", "sparcWorks")
 ifeq ($(shell expr $(COMPILER_REV) \< 5.5), 1)
diff --git a/make/solaris/makefiles/sparcWorks.make b/make/solaris/makefiles/sparcWorks.make
index a20546e6528510f70759e44cba5ad22d68c3b254..942aeb4a4ae4aff6efbed1830abde41c19e72828 100644
--- a/make/solaris/makefiles/sparcWorks.make
+++ b/make/solaris/makefiles/sparcWorks.make
@@ -28,6 +28,8 @@
 CC	= cc
 CPP	= CC
 
+# Note that this 'as' is an older version of the Sun Studio 'fbe', and will
+#   use the older style options. The 'fbe' options will match 'cc' and 'CC'.
 AS	= /usr/ccs/bin/as
 
 NM	= /usr/ccs/bin/nm
@@ -43,25 +45,33 @@ $(shell $(CPP) -V 2>&1 | sed -e 's/^.*\([1-9]\.[0-9][0-9]*\).*/\1/')
 C_COMPILER_REV := \
 $(shell $(CC) -V 2>&1 | grep -i "cc:" |  sed -e 's/^.*\([1-9]\.[0-9][0-9]*\).*/\1/')
 
-VALIDATED_COMPILER_REV   := 5.8
-VALIDATED_C_COMPILER_REV := 5.8
+# Pick which compiler is validated
+ifeq ($(JDK_MINOR_VERSION),6)
+  # Validated compiler for JDK6 is SS11 (5.8)
+  VALIDATED_COMPILER_REV   := 5.8
+  VALIDATED_C_COMPILER_REV := 5.8
+else
+  # FIXUP: Change to SS12 (5.9) once it has been validated.
+  # Validated compiler for JDK7 is SS12 (5.9)
+  #VALIDATED_COMPILER_REV   := 5.9
+  #VALIDATED_C_COMPILER_REV := 5.9
+  VALIDATED_COMPILER_REV   := 5.8
+  VALIDATED_C_COMPILER_REV := 5.8
+endif
 
+# Warning messages about not using the above validated version
 ENFORCE_COMPILER_REV${ENFORCE_COMPILER_REV} := ${VALIDATED_COMPILER_REV}
 ifneq (${COMPILER_REV},${ENFORCE_COMPILER_REV})
-dummy_target_to_enforce_compiler_rev:
-	@echo "Wrong ${CPP} version:  ${COMPILER_REV}. " \
-	"Use version ${ENFORCE_COMPILER_REV}, or set" \
-	"ENFORCE_COMPILER_REV=${COMPILER_REV}."
-	@exit 1
+dummy_target_to_enforce_compiler_rev:=\
+$(info WARNING: You are using CC version ${COMPILER_REV} \
+and should be using version ${ENFORCE_COMPILER_REV})
 endif
 
 ENFORCE_C_COMPILER_REV${ENFORCE_C_COMPILER_REV} := ${VALIDATED_C_COMPILER_REV}
 ifneq (${C_COMPILER_REV},${ENFORCE_C_COMPILER_REV})
-dummy_target_to_enforce_c_compiler_rev:
-	@echo "Wrong ${CC} version:  ${C_COMPILER_REV}. " \
-	"Use version ${ENFORCE_C_COMPILER_REV}, or set" \
-	"ENFORCE_C_COMPILER_REV=${C_COMPILER_REV}."
-	@exit 1
+dummy_target_to_enforce_c_compiler_rev:=\
+$(info WARNING: You are using cc version ${C_COMPILER_REV} \
+and should be using version ${ENFORCE_C_COMPILER_REV})
 endif
 
 # Fail the build if __fabsf is used.  __fabsf exists only in Solaris 8 2/04
@@ -90,20 +100,44 @@ SOLARIS_7_OR_LATER := \
 $(shell uname -r | awk -F. '{ if ($$2 >= 7) print "-DSOLARIS_7_OR_LATER"; }')
 CFLAGS += ${SOLARIS_7_OR_LATER}
 
-ARCHFLAG         = $(ARCHFLAG/$(BUILDARCH))
-# set ARCHFLAG/BUILDARCH which will ultimately be ARCHFLAG
+# New architecture options started in SS12 (5.9), we need both styles to build.
+#   The older arch options for SS11 (5.8) or older and also for /usr/ccs/bin/as.
+#   Note: SS12 default for 32bit sparc is now the same as v8plus, so the
+#         settings below have changed all SS12 32bit sparc builds to be v8plus.
+#         The older SS11 (5.8) settings have remained as they always have been.
 ifeq ($(TYPE),COMPILER2)
-ARCHFLAG/sparc   = -xarch=v8plus
-else
-ifeq ($(TYPE),TIERED)
-ARCHFLAG/sparc   = -xarch=v8plus
+  ARCHFLAG_OLD/sparc   = -xarch=v8plus
 else
-ARCHFLAG/sparc   = -xarch=v8
+  ifeq ($(TYPE),TIERED)
+    ARCHFLAG_OLD/sparc = -xarch=v8plus
+  else
+    ARCHFLAG_OLD/sparc = -xarch=v8
+  endif
 endif
+ARCHFLAG_NEW/sparc   = -m32 -xarch=sparc
+ARCHFLAG_OLD/sparcv9 = -xarch=v9
+ARCHFLAG_NEW/sparcv9 = -m64 -xarch=sparc
+ARCHFLAG_OLD/i486    =
+ARCHFLAG_NEW/i486    = -m32
+ARCHFLAG_OLD/amd64   = -xarch=amd64
+ARCHFLAG_NEW/amd64   = -m64
+
+# Select the ARCHFLAGs and other SS12 (5.9) options
+ifeq ($(shell expr $(COMPILER_REV) \>= 5.9), 1)
+  ARCHFLAG/sparc   = $(ARCHFLAG_NEW/sparc)
+  ARCHFLAG/sparcv9 = $(ARCHFLAG_NEW/sparcv9)
+  ARCHFLAG/i486    = $(ARCHFLAG_NEW/i486)
+  ARCHFLAG/amd64   = $(ARCHFLAG_NEW/amd64)
+else
+  ARCHFLAG/sparc   = $(ARCHFLAG_OLD/sparc)
+  ARCHFLAG/sparcv9 = $(ARCHFLAG_OLD/sparcv9)
+  ARCHFLAG/i486    = $(ARCHFLAG_OLD/i486)
+  ARCHFLAG/amd64   = $(ARCHFLAG_OLD/amd64)
 endif
-ARCHFLAG/sparcv9 = -xarch=v9
-ARCHFLAG/i486  =
-ARCHFLAG/amd64  = -xarch=amd64
+
+# ARCHFLAGS for the current build arch
+ARCHFLAG    = $(ARCHFLAG/$(BUILDARCH))
+AS_ARCHFLAG = $(ARCHFLAG_OLD/$(BUILDARCH))
 
 # Optional sub-directory in /usr/lib where BUILDARCH libraries are kept.
 ISA_DIR=$(ISA_DIR/$(BUILDARCH))
@@ -166,13 +200,13 @@ endif # 32bit x86
 
 ifeq ("${Platform_arch_model}", "x86_64")
 
-ASFLAGS += -xarch=amd64
-CFLAGS  += -xarch=amd64
+ASFLAGS += $(AS_ARCHFLAG)
+CFLAGS  += $(ARCHFLAG/amd64)
 # this one seemed useless
-LFLAGS_VM  += -xarch=amd64
+LFLAGS_VM  += $(ARCHFLAG/amd64)
 # this one worked
-LFLAGS  += -xarch=amd64
-AOUT_FLAGS += -xarch=amd64
+LFLAGS  += $(ARCHFLAG/amd64)
+AOUT_FLAGS += $(ARCHFLAG/amd64)
 
 # -xO3 is faster than -xO4 on specjbb with SS10 compiler
 OPT_CFLAGS=-xO4 $(EXTRA_OPT_CFLAGS)
@@ -224,7 +258,7 @@ LFLAGS += -library=%none
 
 LFLAGS += -mt
 
-endif	# COMPILER_REV >= VALIDATED_COMPILER_REV
+endif	# COMPILER_REV >= 5.5
 
 ######################################
 # End 5.5 Forte compiler options     #
@@ -293,7 +327,7 @@ PICFLAG/BYFILE  = $(PICFLAG/$@)$(PICFLAG/DEFAULT$(PICFLAG/$@))
 LFLAGS += -library=Crun
 LIBS   += -library=Crun -lCrun
 
-endif	# COMPILER_REV >= VALIDATED_COMPILER_REV
+endif	# COMPILER_REV == 5.2
 
 ##################################
 # End 5.2 Forte compiler options #
@@ -320,6 +354,7 @@ ifeq	(${COMPILER_REV}, 5.0)
 
 # Had to hoist this higher apparently because of other changes. Must
 # come before -xarch specification.
+#  NOTE: native says optimize for the machine doing the compile, bad news.
 CFLAGS += -xtarget=native
 
 CFLAGS     += $(ARCHFLAG)
@@ -359,7 +394,7 @@ CFLAGS += $(GAMMADIR)/src/os_cpu/solaris_x86/vm/solaris_x86_32.il
 endif  # 32bit x86
 
 # The following options run into misaligned ldd problem (raj)
-#OPT_CFLAGS = -fast -O4 -xarch=v8 -xchip=ultra
+#OPT_CFLAGS = -fast -O4 $(ARCHFLAG/sparc) -xchip=ultra
 
 # no more exceptions
 CFLAGS/NOEX=-noex
@@ -427,6 +462,15 @@ DEBUG_CFLAGS = -g
 FASTDEBUG_CFLAGS = -g0
 # The -g0 setting allows the C++ frontend to inline, which is a big win.
 
+# Special global options for SS12
+ifeq ($(COMPILER_REV),5.9)
+  # There appears to be multiple issues with the new Dwarf2 debug format, so
+  #   we tell the compiler to use the older 'stabs' debug format all the time.
+  #   Note that this needs to be used in optimized compiles too to be 100%.
+  #   This is a workaround for SS12 (5.9) bug 6694600
+  CFLAGS += -xdebugformat=stabs
+endif
+
 # Enable the following CFLAGS additions if you need to compare the
 # built ELF objects.
 #
diff --git a/make/solaris/makefiles/sparcv9.make b/make/solaris/makefiles/sparcv9.make
index 985b7b47135927fa22d4e7b31d651b61b0d80cd4..62711f07d34d97fb8d59b70c897ed16e95ce10df 100644
--- a/make/solaris/makefiles/sparcv9.make
+++ b/make/solaris/makefiles/sparcv9.make
@@ -23,7 +23,7 @@
 #
 
 Obj_Files += solaris_sparc.o
-ASFLAGS += $(ARCHFLAG)
+ASFLAGS += $(AS_ARCHFLAG)
 
 ifeq ("${Platform_compiler}", "sparcWorks")
 ifeq ($(shell expr $(COMPILER_REV) \< 5.5), 1)