diff --git a/.gitignore b/.gitignore
index d9c4a7972f076d..547e6746e1d91b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -122,8 +122,7 @@ Tools/unicode/data/
 # hendrikmuhs/ccache-action@v1
 /.ccache
 /platform
-/profile-clean-stamp
-/profile-run-stamp
+/profile-*-stamp
 /Python/deepfreeze/*.c
 /pybuilddir.txt
 /pyconfig.h
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 2f9f4a1c5870ca..b22f70f661e74b 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -38,7 +38,6 @@ CC=		@CC@
 CXX=		@CXX@
 LINKCC=		@LINKCC@
 AR=		@AR@
-READELF=	@READELF@
 SOABI=		@SOABI@
 LDVERSION=	@LDVERSION@
 LIBPYTHON=	@LIBPYTHON@
@@ -601,13 +600,27 @@ LIBHACL_SHA2_HEADERS= \
 #########################################################################
 # Rules
 
-# Default target
-all:		@DEF_MAKE_ALL_RULE@
+# Default target.
+# Likely either `build-plain` or `build-optimized`.
+all: @MAKE_TARGET_ALL@
 
 # First target in Makefile is implicit default. So .PHONY needs to come after
 # all.
 .PHONY: all
 
+# Build without any optimizations or instrumented binaries.
+.PHONY: build-plain
+build-plain: @MAKE_TARGET_BUILD_PLAIN@
+
+# Build with optimizations (PGO, BOLT, etc).
+.PHONY: build-optimized
+build-optimized: @MAKE_TARGET_BUILD_OPTIMIZED@
+
+.PHONY: build-optimized-not-enabled
+build-optimized-not-enabled:
+	@echo "build-optimized requires --enable-optimizations in configure; aborting"
+	@exit 1
+
 .PHONY: build_all
 build_all:	check-clean-src $(BUILDPYTHON) platform sharedmods \
 		gdbhooks Programs/_testembed scripts checksharedmods rundsymutil
@@ -629,69 +642,145 @@ check-clean-src:
 		exit 1; \
 	fi
 
-# Profile generation build must start from a clean tree.
+# Profile-based optimization.
+#
+# PGO and BOLT profile-based optimization is supported. For each optimization,
+# roughly the following steps are done:
+#
+# 1. "Instrument" binaries with run-time data collection (e.g. build or modify
+#    a variant of the binary.)
+# 2. "Run" instrumented binaries (via subset of test suite) to collect data.
+# 3. "Analyze" / collect / merge data files from previous step.
+# 4. "Apply" collected data from above. (e.g. rebuild or modify a binary).
+#
+# 0, 1, or multiple profile based optimizations can be enabled.
+#
+# We track the progress of profile-based optimization using various "stamp"
+# files. An empty stamp file tracks the stage of optimization we're in.
+# Each *-stamp rule that follows is defined in execution / dependency order.
+
+# Remove files produced by or used for tracking profile-guided optimization.
+.PHONY: profile-remove
+profile-remove: clean-bolt
+	find . -name '*.gc??' -exec rm -f {} ';'
+	find . -name '*.profclang?' -exec rm -f {} ';'
+	find . -name '*.dyn' -exec rm -f {} ';'
+	rm -f $(COVERAGE_INFO)
+	rm -rf $(COVERAGE_REPORT)
+	# Remove all progress tracking stamps to ensure a clean slate.
+	rm -f profile-*-stamp
+
+# Profile-based optimization requires a fresh build environment.
 profile-clean-stamp:
-	$(MAKE) clean
+	$(MAKE) clean profile-remove
 	touch $@
 
-# Compile with profile generation enabled.
-profile-gen-stamp: profile-clean-stamp
+# Build with PGO instrumentation enabled.
+profile-pgo-instrument-stamp: profile-clean-stamp
 	@if [ $(LLVM_PROF_ERR) = yes ]; then \
 		echo "Error: Cannot perform PGO build because llvm-profdata was not found in PATH" ;\
 		echo "Please add it to PATH and run ./configure again" ;\
 		exit 1;\
 	fi
 	@echo "Building with support for profile generation:"
-	$(MAKE) @DEF_MAKE_RULE@ CFLAGS_NODIST="$(CFLAGS_NODIST) $(PGO_PROF_GEN_FLAG)" LDFLAGS_NODIST="$(LDFLAGS_NODIST) $(PGO_PROF_GEN_FLAG)" LIBS="$(LIBS)"
+	$(MAKE) @MAKE_TARGET_BUILD_PLAIN@ CFLAGS_NODIST="$(CFLAGS_NODIST) $(PGO_PROF_GEN_FLAG)" LDFLAGS_NODIST="$(LDFLAGS_NODIST) $(PGO_PROF_GEN_FLAG)" LIBS="$(LIBS)"
 	touch $@
 
-# Run task with profile generation build to create profile information.
-profile-run-stamp:
+# Run PGO instrumented binaries and collect profile data.
+profile-pgo-run-stamp: profile-pgo-instrument-stamp
 	@echo "Running code to generate profile data (this can take a while):"
-	# First, we need to create a clean build with profile generation
-	# enabled.
-	$(MAKE) profile-gen-stamp
-	# Next, run the profile task to generate the profile information.
 	@ # FIXME: can't run for a cross build
 	$(LLVM_PROF_FILE) $(RUNSHARED) ./$(BUILDPYTHON) $(PROFILE_TASK) || true
+	touch $@
+
+# Collect data files produced by running PGO instrumented binaries.
+profile-pgo-analyze-stamp: profile-pgo-run-stamp
 	$(LLVM_PROF_MERGER)
 	# Remove profile generation binary since we are done with it.
 	$(MAKE) clean-retain-profile
-	# This is an expensive target to build and it does not have proper
-	# makefile dependency information.  So, we create a "stamp" file
-	# to record its completion and avoid re-running it.
 	touch $@
 
-# Compile Python binary with profile guided optimization.
-# To force re-running of the profile task, remove the profile-run-stamp file.
-.PHONY: profile-opt
-profile-opt: profile-run-stamp
+# Use collected PGO data to influence rebuild of binaries.
+profile-pgo-apply-stamp: profile-pgo-analyze-stamp
 	@echo "Rebuilding with profile guided optimizations:"
-	-rm -f profile-clean-stamp
-	$(MAKE) @DEF_MAKE_RULE@ CFLAGS_NODIST="$(CFLAGS_NODIST) $(PGO_PROF_USE_FLAG)" LDFLAGS_NODIST="$(LDFLAGS_NODIST)"
-
-.PHONY: bolt-opt
-bolt-opt: @PREBOLT_RULE@
-	rm -f *.fdata
-	@if $(READELF) -p .note.bolt_info $(BUILDPYTHON) | grep BOLT > /dev/null; then\
-		echo "skip: $(BUILDPYTHON) is already BOLTed."; \
-	else \
-		@LLVM_BOLT@ ./$(BUILDPYTHON) -instrument -instrumentation-file-append-pid -instrumentation-file=$(abspath $(BUILDPYTHON).bolt) -o $(BUILDPYTHON).bolt_inst; \
-		./$(BUILDPYTHON).bolt_inst $(PROFILE_TASK) || true; \
-		@MERGE_FDATA@ $(BUILDPYTHON).*.fdata > $(BUILDPYTHON).fdata; \
-		@LLVM_BOLT@ ./$(BUILDPYTHON) -o $(BUILDPYTHON).bolt -data=$(BUILDPYTHON).fdata -update-debug-sections -reorder-blocks=ext-tsp -reorder-functions=hfsort+ -split-functions -icf=1 -inline-all -split-eh -reorder-functions-use-hot-size -peepholes=none -jump-tables=aggressive -inline-ap -indirect-call-promotion=all -dyno-stats -use-gnu-stack -frame-opt=hot; \
-		rm -f *.fdata; \
-		rm -f $(BUILDPYTHON).bolt_inst; \
-		mv $(BUILDPYTHON).bolt $(BUILDPYTHON); \
+	# Need to purge PGO instrumented build to force a rebuild.
+	$(MAKE) clean-retain-profile
+	$(MAKE) @MAKE_TARGET_BUILD_PLAIN@ CFLAGS_NODIST="$(CFLAGS_NODIST) $(PGO_PROF_USE_FLAG)" LDFLAGS_NODIST="$(LDFLAGS_NODIST)"
+	touch $@
+
+# BOLT supports instrumenting and applying changes to standalone binaries
+# without having to recompile.
+#
+# BOLT can run independently or in addition to PGO. If running with PGO,
+# it always runs after PGO. Care needs to be taken to preserve PGO state
+# when running BOLT so make doesn't re-apply PGO.
+#
+# BOLT also can't instrument binaries that have already had BOLT applied
+# to them. So we make an attempt to preserve and re-use the pristine
+# pre-BOLT binaries so developers can iterate on just BOLT optimization
+# passes.
+
+# List of binaries that BOLT runs on.
+BOLT_BINARIES = $(BUILDPYTHON)
+
+# Remove traces of bolt.
+.PHONY: clean-bolt
+clean-bolt:
+	# Instrumented binaries.
+	find . -name '*.bolt_inst' -exec rm -f {} ';'
+	# The data files they produce.
+	find . -name '*.fdata' -exec rm -f {} ';'
+	# Copied of binaries before BOLT application.
+	find . -name '*.prebolt' -exec rm -f {} ';'
+
+# BOLTs dependencies are a bit wonky.
+#
+# If PGO is enabled, we can take a native rule dependency on a stamp file.
+# If PGO isn't enabled, we don't have a stamp to key off of and the phony
+# target (e.g. build_all) will always force rebuilds. So we call out to
+# make externally to sidestep the dependency.
+#
+# We can simplify this hack if we ever get stamp files for plain builds.
+profile-bolt-prebuild-stamp: @MAKE_BOLT_NATIVE_DEPENDENCY@
+	if [ -n "@MAKE_BOLT_MAKE_DEPENDENCY@" ]; then \
+	    $(MAKE) @MAKE_BOLT_MAKE_DEPENDENCY@; \
 	fi
+	touch $@
 
+profile-bolt-instrument-stamp: profile-bolt-prebuild-stamp
+	for bin in $(BOLT_BINARIES); do \
+	    if [ -e "$${bin}.prebolt" ]; then \
+	        echo "Restoring pre-BOLT binary $${bin}.prebolt"; \
+	        mv "$${bin}.prebolt" "$${bin}"; \
+	    fi \
+	done
+	# Ensure prior BOLT state is purged.
+	$(MAKE) clean-bolt
+	@LLVM_BOLT@ ./$(BUILDPYTHON) -instrument -instrumentation-file-append-pid -instrumentation-file=$(abspath $(BUILDPYTHON).bolt) -o $(BUILDPYTHON).bolt_inst
+	touch $@
+
+profile-bolt-run-stamp: profile-bolt-instrument-stamp
+	./$(BUILDPYTHON).bolt_inst $(PROFILE_TASK) || true
+	touch $@
+
+profile-bolt-analyze-stamp: profile-bolt-run-stamp
+	@MERGE_FDATA@ $(BUILDPYTHON).*.fdata > $(BUILDPYTHON).fdata
+	touch $@
+
+profile-bolt-apply-stamp: profile-bolt-analyze-stamp
+	@LLVM_BOLT@ ./$(BUILDPYTHON) -o $(BUILDPYTHON).bolt -data=$(BUILDPYTHON).fdata -update-debug-sections -reorder-blocks=ext-tsp -reorder-functions=hfsort+ -split-functions=3 -icf=1 -inline-all -split-eh -reorder-functions-use-hot-size -peepholes=all -jump-tables=aggressive -inline-ap -indirect-call-promotion=all -dyno-stats -use-gnu-stack -frame-opt=hot
+	mv $(BUILDPYTHON) $(BUILDPYTHON).prebolt
+	mv $(BUILDPYTHON).bolt $(BUILDPYTHON)
+	touch $@
+
+# End of profile-based optimization rules.
 
 # Compile and run with gcov
 .PHONY: coverage
 coverage:
 	@echo "Building with support for coverage checking:"
 	$(MAKE) clean
-	$(MAKE) @DEF_MAKE_RULE@ CFLAGS="$(CFLAGS) -O0 -pg --coverage" LDFLAGS="$(LDFLAGS) --coverage"
+	$(MAKE) @MAKE_SIMPLE_BUILD_TARGET@ CFLAGS="$(CFLAGS) -O0 -pg --coverage" LDFLAGS="$(LDFLAGS) --coverage"
 
 .PHONY: coverage-lcov
 coverage-lcov:
@@ -2610,23 +2699,9 @@ clean-retain-profile: pycremoval
 	-rm -f Python/frozen_modules/MANIFEST
 	-find build -type f -a ! -name '*.gc??' -exec rm -f {} ';'
 	-rm -f Include/pydtrace_probes.h
-	-rm -f profile-gen-stamp
-
-.PHONY: profile-removal
-profile-removal:
-	find . -name '*.gc??' -exec rm -f {} ';'
-	find . -name '*.profclang?' -exec rm -f {} ';'
-	find . -name '*.dyn' -exec rm -f {} ';'
-	rm -f $(COVERAGE_INFO)
-	rm -rf $(COVERAGE_REPORT)
-	rm -f profile-run-stamp
 
 .PHONY: clean
 clean: clean-retain-profile
-	@if test @DEF_MAKE_ALL_RULE@ = profile-opt; then \
-		rm -f profile-gen-stamp profile-clean-stamp; \
-		$(MAKE) profile-removal; \
-	fi
 
 .PHONY: clobber
 clobber: clean
diff --git a/configure b/configure
index 7aad4fe89e3cbf..efad1988a2ff8e 100755
--- a/configure
+++ b/configure
@@ -885,9 +885,8 @@ CFLAGS_ALIASING
 OPT
 MERGE_FDATA
 LLVM_BOLT
-ac_ct_READELF
-READELF
-PREBOLT_RULE
+MAKE_BOLT_MAKE_DEPENDENCY
+MAKE_BOLT_NATIVE_DEPENDENCY
 LLVM_PROF_FOUND
 LLVM_PROFDATA
 LLVM_PROF_ERR
@@ -898,8 +897,9 @@ PGO_PROF_GEN_FLAG
 LLVM_AR_FOUND
 LLVM_AR
 PROFILE_TASK
-DEF_MAKE_RULE
-DEF_MAKE_ALL_RULE
+MAKE_TARGET_BUILD_OPTIMIZED
+MAKE_TARGET_BUILD_PLAIN
+MAKE_TARGET_ALL
 ABIFLAGS
 LN
 MKDIR_P
@@ -7448,7 +7448,17 @@ $as_echo "no" >&6; }
 fi
 
 # Enable optimization flags
+# Which target `all` (the default make target) depends on.
 
+# Which target to evaluate for non-optimized builds.
+
+
+
+# Do a non-optimized generic build by default. Build configurations below
+# can override as appropriate.
+MAKE_TARGET_ALL="build-plain"
+MAKE_TARGET_BUILD_PLAIN="build_all"
+MAKE_TARGET_BUILD_OPTIMIZED="build-optimized-not-enabled"
 
 Py_OPT='false'
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --enable-optimizations" >&5
@@ -7473,13 +7483,15 @@ fi
 
 
 if test "$Py_OPT" = 'true' ; then
+  # PGO is implied by optimizations mode.
+  PGO_ENABLED=1
+  MAKE_TARGET_ALL="build-optimized"
+  MAKE_TARGET_BUILD_OPTIMIZED="profile-pgo-apply-stamp"
+
   # Intentionally not forcing Py_LTO='true' here.  Too many toolchains do not
   # compile working code using it and both test_distutils and test_gdb are
   # broken when you do manage to get a toolchain that works with it.  People
   # who want LTO need to use --with-lto themselves.
-  DEF_MAKE_ALL_RULE="profile-opt"
-  REQUIRE_PGO="yes"
-  DEF_MAKE_RULE="build_all"
   case $CC in
     *gcc*)
       { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether C compiler accepts -fno-semantic-interposition" >&5
@@ -7523,13 +7535,7 @@ fi
       ;;
   esac
 elif test "$ac_sys_system" = "Emscripten" -o "$ac_sys_system" = "WASI"; then
-      DEF_MAKE_ALL_RULE="build_wasm"
-  REQUIRE_PGO="no"
-  DEF_MAKE_RULE="all"
-else
-  DEF_MAKE_ALL_RULE="build_all"
-  REQUIRE_PGO="no"
-  DEF_MAKE_RULE="all"
+      MAKE_TARGET_BUILD_PLAIN="build_wasm"
 fi
 
 
@@ -8039,7 +8045,8 @@ case $CC in
     if test $LLVM_PROF_FOUND = not-found
     then
       LLVM_PROF_ERR=yes
-      if test "${REQUIRE_PGO}" = "yes"
+
+      if test -n "${ENABLE_PGO}"
       then
         as_fn_error $? "llvm-profdata is required for a --enable-optimizations build but could not be found." "$LINENO" 5
       fi
@@ -8055,10 +8062,10 @@ case $CC in
         if test "${LLVM_PROF_FOUND}" = "not-found"
         then
           LLVM_PROF_ERR=yes
-          if test "${REQUIRE_PGO}" = "yes"
-	  then
-	    as_fn_error $? "llvm-profdata is required for a --enable-optimizations build but could not be found." "$LINENO" 5
-	  fi
+          if test -n "${ENABLE_PGO}"
+          then
+            as_fn_error $? "llvm-profdata is required for a --enable-optimizations build but could not be found." "$LINENO" 5
+          fi
         fi
         ;;
       *)
@@ -8101,115 +8108,18 @@ fi
 
 
 
-if test "$Py_BOLT" = 'true' ; then
-  PREBOLT_RULE="${DEF_MAKE_ALL_RULE}"
-  DEF_MAKE_ALL_RULE="bolt-opt"
-  DEF_MAKE_RULE="build_all"
-
-
-  if test -n "$ac_tool_prefix"; then
-  for ac_prog in readelf
-  do
-    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
-set dummy $ac_tool_prefix$ac_prog; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_READELF+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$READELF"; then
-  ac_cv_prog_READELF="$READELF" # Let the user override the test.
-else
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_READELF="$ac_tool_prefix$ac_prog"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
-
-fi
-fi
-READELF=$ac_cv_prog_READELF
-if test -n "$READELF"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $READELF" >&5
-$as_echo "$READELF" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
 
 
-    test -n "$READELF" && break
-  done
-fi
-if test -z "$READELF"; then
-  ac_ct_READELF=$READELF
-  for ac_prog in readelf
-do
-  # Extract the first word of "$ac_prog", so it can be a program name with args.
-set dummy $ac_prog; ac_word=$2
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
-$as_echo_n "checking for $ac_word... " >&6; }
-if ${ac_cv_prog_ac_ct_READELF+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  if test -n "$ac_ct_READELF"; then
-  ac_cv_prog_ac_ct_READELF="$ac_ct_READELF" # Let the user override the test.
-else
-as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
-for as_dir in $PATH
-do
-  IFS=$as_save_IFS
-  test -z "$as_dir" && as_dir=.
-    for ac_exec_ext in '' $ac_executable_extensions; do
-  if as_fn_executable_p "$as_dir/$ac_word$ac_exec_ext"; then
-    ac_cv_prog_ac_ct_READELF="$ac_prog"
-    $as_echo "$as_me:${as_lineno-$LINENO}: found $as_dir/$ac_word$ac_exec_ext" >&5
-    break 2
-  fi
-done
-  done
-IFS=$as_save_IFS
-
-fi
-fi
-ac_ct_READELF=$ac_cv_prog_ac_ct_READELF
-if test -n "$ac_ct_READELF"; then
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_ct_READELF" >&5
-$as_echo "$ac_ct_READELF" >&6; }
-else
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-fi
-
-
-  test -n "$ac_ct_READELF" && break
-done
-
-  if test "x$ac_ct_READELF" = x; then
-    READELF=""notfound""
-  else
-    case $cross_compiling:$ac_tool_warned in
-yes:)
-{ $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
-$as_echo "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
-ac_tool_warned=yes ;;
-esac
-    READELF=$ac_ct_READELF
-  fi
-fi
+if test "$Py_BOLT" = 'true' ; then
+  MAKE_TARGET_BUILD_OPTIMIZED="profile-bolt-apply-stamp"
 
-  if test "$READELF" == "notfound"
+  # Hook up make dependencies differently depending on whether PGO is
+  # enabled. See inline comment in Makefile.pre.in for how this works.
+  if test -n "${PGO_ENABLED}"
   then
-    as_fn_error $? "readelf is required for a --enable-bolt build but could not be found." "$LINENO" 5
+    MAKE_BOLT_NATIVE_DEPENDENCY="profile-pgo-apply-stamp"
+  else
+    MAKE_BOLT_MAKE_DEPENDENCY="${MAKE_TARGET_BUILD_PLAIN}"
   fi
 
   # -fno-reorder-blocks-and-partition is required for bolt to work.
diff --git a/configure.ac b/configure.ac
index 115998e0753b26..073f6070876225 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1722,8 +1722,18 @@ else
 fi
 
 # Enable optimization flags
-AC_SUBST(DEF_MAKE_ALL_RULE)
-AC_SUBST(DEF_MAKE_RULE)
+# Which target `all` (the default make target) depends on.
+AC_SUBST(MAKE_TARGET_ALL)
+# Which target to evaluate for non-optimized builds.
+AC_SUBST(MAKE_TARGET_BUILD_PLAIN)
+AC_SUBST(MAKE_TARGET_BUILD_OPTIMIZED)
+
+# Do a non-optimized generic build by default. Build configurations below
+# can override as appropriate.
+MAKE_TARGET_ALL="build-plain"
+MAKE_TARGET_BUILD_PLAIN="build_all"
+MAKE_TARGET_BUILD_OPTIMIZED="build-optimized-not-enabled"
+
 Py_OPT='false'
 AC_MSG_CHECKING(for --enable-optimizations)
 AC_ARG_ENABLE(optimizations, AS_HELP_STRING(
@@ -1741,13 +1751,15 @@ fi],
 [AC_MSG_RESULT(no)])
 
 if test "$Py_OPT" = 'true' ; then
+  # PGO is implied by optimizations mode.
+  PGO_ENABLED=1
+  MAKE_TARGET_ALL="build-optimized"
+  MAKE_TARGET_BUILD_OPTIMIZED="profile-pgo-apply-stamp"
+
   # Intentionally not forcing Py_LTO='true' here.  Too many toolchains do not
   # compile working code using it and both test_distutils and test_gdb are
   # broken when you do manage to get a toolchain that works with it.  People
   # who want LTO need to use --with-lto themselves.
-  DEF_MAKE_ALL_RULE="profile-opt"
-  REQUIRE_PGO="yes"
-  DEF_MAKE_RULE="build_all"
   case $CC in
     *gcc*)
       AX_CHECK_COMPILE_FLAG([-fno-semantic-interposition],[
@@ -1759,13 +1771,7 @@ if test "$Py_OPT" = 'true' ; then
 elif test "$ac_sys_system" = "Emscripten" -o "$ac_sys_system" = "WASI"; then
   dnl Emscripten does not support shared extensions yet. Build
   dnl "python.[js,wasm]", "pybuilddir.txt", and "platform" files.
-  DEF_MAKE_ALL_RULE="build_wasm"
-  REQUIRE_PGO="no"
-  DEF_MAKE_RULE="all"
-else
-  DEF_MAKE_ALL_RULE="build_all"
-  REQUIRE_PGO="no"
-  DEF_MAKE_RULE="all"
+  MAKE_TARGET_BUILD_PLAIN="build_wasm"
 fi
 
 AC_ARG_VAR(PROFILE_TASK, Python args for PGO generation task)
@@ -1967,7 +1973,8 @@ case $CC in
     if test $LLVM_PROF_FOUND = not-found
     then
       LLVM_PROF_ERR=yes
-      if test "${REQUIRE_PGO}" = "yes"
+
+      if test -n "${ENABLE_PGO}"
       then
         AC_MSG_ERROR([llvm-profdata is required for a --enable-optimizations build but could not be found.])
       fi
@@ -1983,10 +1990,10 @@ case $CC in
         if test "${LLVM_PROF_FOUND}" = "not-found"
         then
           LLVM_PROF_ERR=yes
-          if test "${REQUIRE_PGO}" = "yes"
-	  then
-	    AC_MSG_ERROR([llvm-profdata is required for a --enable-optimizations build but could not be found.])
-	  fi
+          if test -n "${ENABLE_PGO}"
+          then
+            AC_MSG_ERROR([llvm-profdata is required for a --enable-optimizations build but could not be found.])
+          fi
         fi
         ;;
       *)
@@ -2022,17 +2029,19 @@ else
 fi],
 [AC_MSG_RESULT(no)])
 
-AC_SUBST(PREBOLT_RULE)
+AC_SUBST(MAKE_BOLT_NATIVE_DEPENDENCY)
+AC_SUBST(MAKE_BOLT_MAKE_DEPENDENCY)
+
 if test "$Py_BOLT" = 'true' ; then
-  PREBOLT_RULE="${DEF_MAKE_ALL_RULE}"
-  DEF_MAKE_ALL_RULE="bolt-opt"
-  DEF_MAKE_RULE="build_all"
+  MAKE_TARGET_BUILD_OPTIMIZED="profile-bolt-apply-stamp"
 
-  AC_SUBST(READELF)
-  AC_CHECK_TOOLS(READELF, [readelf], "notfound")
-  if test "$READELF" == "notfound"
+  # Hook up make dependencies differently depending on whether PGO is
+  # enabled. See inline comment in Makefile.pre.in for how this works.
+  if test -n "${PGO_ENABLED}"
   then
-    AC_MSG_ERROR([readelf is required for a --enable-bolt build but could not be found.])
+    MAKE_BOLT_NATIVE_DEPENDENCY="profile-pgo-apply-stamp"
+  else
+    MAKE_BOLT_MAKE_DEPENDENCY="${MAKE_TARGET_BUILD_PLAIN}"
   fi
 
   # -fno-reorder-blocks-and-partition is required for bolt to work.