From 50d75cbc963824ae7fc5137dd56ce9e01762a233 Mon Sep 17 00:00:00 2001
From: James Clarke <jrtc27@jrtc27.com>
Date: Wed, 11 Dec 2019 00:24:11 +0000
Subject: [PATCH 1/3] benchmarks: Don't use GCC's C nested function extension

It's unnecessary and non-portable; Clang doesn't even implement that
part of GNU C.
---
 benchmarks/common/syscalls.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/benchmarks/common/syscalls.c b/benchmarks/common/syscalls.c
index 39547b3d0..db2d4d7f2 100644
--- a/benchmarks/common/syscalls.c
+++ b/benchmarks/common/syscalls.c
@@ -356,19 +356,19 @@ int printf(const char* fmt, ...)
   return 0; // incorrect return value, but who cares, anyway?
 }
 
+static void sprintf_putch(int ch, void** data)
+{
+  char** pstr = (char**)data;
+  **pstr = ch;
+  (*pstr)++;
+}
+
 int sprintf(char* str, const char* fmt, ...)
 {
   va_list ap;
   char* str0 = str;
   va_start(ap, fmt);
 
-  void sprintf_putch(int ch, void** data)
-  {
-    char** pstr = (char**)data;
-    **pstr = ch;
-    (*pstr)++;
-  }
-
   vprintfmt(sprintf_putch, (void**)&str, fmt, ap);
   *str = 0;
 

From 65baa582996129209a84ee5b62a9b00eced01b45 Mon Sep 17 00:00:00 2001
From: James Clarke <jrtc27@jrtc27.com>
Date: Wed, 11 Dec 2019 00:39:01 +0000
Subject: [PATCH 2/3] benchmarks: Pass -T to the linker

Clang's driver does not seem to forward this on, unlike GCC's, so
instead ensure the linker sees it by using -Wl.
---
 benchmarks/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/benchmarks/Makefile b/benchmarks/Makefile
index fb0d2977d..cd3c975bd 100644
--- a/benchmarks/Makefile
+++ b/benchmarks/Makefile
@@ -38,8 +38,8 @@ bmarks = \
 RISCV_PREFIX ?= riscv$(XLEN)-unknown-elf-
 RISCV_GCC ?= $(RISCV_PREFIX)gcc
 RISCV_GCC_OPTS ?= -DPREALLOCATE=1 -mcmodel=medany -static -std=gnu99 -O2 -ffast-math -fno-common -fno-builtin-printf
-RISCV_LINK ?= $(RISCV_GCC) -T $(src_dir)/common/test.ld $(incs)
-RISCV_LINK_OPTS ?= -static -nostdlib -nostartfiles -lm -lgcc -T $(src_dir)/common/test.ld
+RISCV_LINK ?= $(RISCV_GCC) -Wl,-T,$(src_dir)/common/test.ld $(incs)
+RISCV_LINK_OPTS ?= -static -nostdlib -nostartfiles -lm -lgcc -Wl,-T,$(src_dir)/common/test.ld
 RISCV_OBJDUMP ?= $(RISCV_PREFIX)objdump --disassemble-all --disassemble-zeroes --section=.text --section=.text.startup --section=.data
 RISCV_SIM ?= spike --isa=rv$(XLEN)gc
 

From 20378c0bdd2f5cdd2bfc6036c88c523e7908bada Mon Sep 17 00:00:00 2001
From: James Clarke <jrtc27@jrtc27.com>
Date: Wed, 11 Dec 2019 00:39:48 +0000
Subject: [PATCH 3/3] benchmarks: Fix init_tls on Clang

Clang only supports register variables when declared at global scope
(and only for non-allocatable registers, which is fine for tp), so move
thread_pointer. This does not make thread_pointer visible outside the
translation unit, it merely acts as a C alias for tp, so the semantics
remain unchanged.
---
 benchmarks/common/syscalls.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/benchmarks/common/syscalls.c b/benchmarks/common/syscalls.c
index db2d4d7f2..cc43c9081 100644
--- a/benchmarks/common/syscalls.c
+++ b/benchmarks/common/syscalls.c
@@ -93,9 +93,11 @@ int __attribute__((weak)) main(int argc, char** argv)
   return -1;
 }
 
+// Must be global for compatibility with Clang
+register void* thread_pointer asm("tp");
+
 static void init_tls()
 {
-  register void* thread_pointer asm("tp");
   extern char _tdata_begin, _tdata_end, _tbss_end;
   size_t tdata_size = &_tdata_end - &_tdata_begin;
   memcpy(thread_pointer, &_tdata_begin, tdata_size);