From 3b7cc74d39ec6263be4a45a479bc0d1ce9fab0ce Mon Sep 17 00:00:00 2001
From: Stan Hu <stanhu@gmail.com>
Date: Wed, 25 Aug 2021 00:33:43 -0700
Subject: [PATCH] Drop ABSL_RANDOM_HWAES_FLAGS compiler flags

Older CPUs that do not have SSE4.1 would crash with the Ruby native gem
due to an illegal instruction exception.

The Abseil random library isn't being used at the moment
(https://github.com/grpc/grpc/pull/26476), and there's no reason gRPC
needs to force SSE4.1 instructions on all platforms at the moment. There
are other hardware-specific issues that need to be ironed out for this
to work: https://github.com/grpc/grpc/pull/26479

When the `-msse4` compiler flag was enabled, the Abseil code started
using the `pinsrb` instruction:

```
$ elfx86exts abseil-cpp/absl/time/internal/cctz/src/time_zone_libc.o
MODE64 (ret)
CMOV (cmovne)
SSE2 (movdqa)
SSE41 (pinsrb)
SSE1 (movaps)
CPU Generation: Penryn
```

Closes https://github.com/grpc/grpc/issues/27095
---
 Makefile                    | 15 +--------------
 build_handwritten.yaml      |  2 +-
 templates/Makefile.template | 13 -------------
 3 files changed, 2 insertions(+), 28 deletions(-)

diff --git a/Makefile b/Makefile
index fd98ab5a60a..7f9030e170f 100644
--- a/Makefile
+++ b/Makefile
@@ -34,14 +34,6 @@ ifeq ($(SYSTEM),MINGW64)
 SYSTEM = MINGW32
 endif
 
-# Basic machine detection
-HOST_MACHINE = $(shell uname -m)
-ifeq ($(HOST_MACHINE),x86_64)
-HOST_IS_X86_64 = true
-else
-HOST_IS_X86_64 = false
-endif
-
 MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
 ifndef BUILDDIR
 BUILDDIR_ABSOLUTE = $(patsubst %/,%,$(dir $(MAKEFILE_PATH)))
@@ -578,11 +570,6 @@ CPPFLAGS := -Ithird_party/address_sorting/include $(CPPFLAGS)
 
 GRPC_ABSEIL_DEP = $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a
 GRPC_ABSEIL_MERGE_LIBS = $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a
-ifeq ($(HOST_IS_X86_64),true)
-ABSL_RANDOM_HWAES_FLAGS = -maes -msse4
-else
-ABSL_RANDOM_HWAES_FLAGS =
-endif
 
 # Setup re2 dependency
 
@@ -2680,7 +2667,7 @@ LIBGRPC_ABSEIL_SRC = \
 
 LIBGRPC_ABSEIL_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(LIBGRPC_ABSEIL_SRC))))
 
-$(LIBGRPC_ABSEIL_OBJS): CPPFLAGS += -g $(ABSL_RANDOM_HWAES_FLAGS) -Ithird_party/abseil-cpp
+$(LIBGRPC_ABSEIL_OBJS): CPPFLAGS += -Ithird_party/abseil-cpp
 
 $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a:  $(LIBGRPC_ABSEIL_OBJS) 
 	$(E) "[AR]      Creating $@"
diff --git a/build_handwritten.yaml b/build_handwritten.yaml
index 13b1b73df0f..d33482cda22 100644
--- a/build_handwritten.yaml
+++ b/build_handwritten.yaml
@@ -165,7 +165,7 @@ configs:
       UBSAN_OPTIONS: halt_on_error=1:print_stacktrace=1:suppressions=test/core/util/ubsan_suppressions.txt
 defaults:
   abseil:
-    CPPFLAGS: -g $(ABSL_RANDOM_HWAES_FLAGS) -Ithird_party/abseil-cpp
+    CPPFLAGS: -Ithird_party/abseil-cpp
   ares:
     CFLAGS: -g
     CPPFLAGS: -Ithird_party/cares -Ithird_party/cares/cares -fvisibility=hidden -D_GNU_SOURCE
diff --git a/templates/Makefile.template b/templates/Makefile.template
index 5afb36ce6a4..bdb172b7ae2 100644
--- a/templates/Makefile.template
+++ b/templates/Makefile.template
@@ -74,14 +74,6 @@
   SYSTEM = MINGW32
   endif
 
-  # Basic machine detection
-  HOST_MACHINE = $(shell uname -m)
-  ifeq ($(HOST_MACHINE),x86_64)
-  HOST_IS_X86_64 = true
-  else
-  HOST_IS_X86_64 = false
-  endif
-
   MAKEFILE_PATH := $(abspath $(lastword $(MAKEFILE_LIST)))
   ifndef BUILDDIR
   BUILDDIR_ABSOLUTE = $(patsubst %/,%,$(dir $(MAKEFILE_PATH)))
@@ -441,11 +433,6 @@
 
   GRPC_ABSEIL_DEP = $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a
   GRPC_ABSEIL_MERGE_LIBS = $(LIBDIR)/$(CONFIG)/libgrpc_abseil.a
-  ifeq ($(HOST_IS_X86_64),true)
-  ABSL_RANDOM_HWAES_FLAGS = -maes -msse4
-  else
-  ABSL_RANDOM_HWAES_FLAGS =
-  endif
 
   # Setup re2 dependency