From 51912d55056938abad8b5be141729e9c259ee5d1 Mon Sep 17 00:00:00 2001
From: Johny Mattsson <jmattsson@dius.com.au>
Date: Sat, 22 Jun 2019 12:05:34 +1000
Subject: [PATCH] Reworked linker magic to work with IDF 3.3 (#2805)

With the IDF asserting full control over the linker scripts and insisting on
the application description being the first entry in the .flash.rodata
section, or previous method of doing link-time arrays stopped working.
Why? Because the build patched in a SHA256 digest straight into our arrays.

With the limited language of the gcc linker scripts I could find no other
way of getting it in cleanly.

The IDF "linker fragments" support can not be made to work for our needs:
  - no support for setting alignment before including objects
  - no support for declaring symbols
  - no support for adding our terminating zeros
  - insists on grouping objects by lib rather than by declared grouping,
    which means we could at most have a single link-time-array using
    the IDF mechanism
  - also does not like underscores in section names, but that's just an
    annoyance

So, the least bad option that I could come up with was to use a project-wide
makefile snippet to add a target in-between the IDF's generation of the
esp32.project.ld file, and the linking of our NodeMCU.elf. In this target
we read in the esp32.project.ld linker script, check whether we have our
arrays in there, and if not rewrites the linker script.

Oh, and the esp32.project.ld file only came into existence on the IDF 3.3
branch, so I had to change up the IDF to the latest release/3.3 as well.
I would've preferred a stable tag, but the v3.3-beta3 had a really nasty
regression for us (can't add partition entry), so that was a no-go.
---
 components/base_nodemcu/Makefile.projbuild    |  8 ++++++
 components/base_nodemcu/add_rodata_ld.sh      | 27 +++++++++++++++++++
 components/base_nodemcu/component.mk          |  4 ---
 .../ld/{nodemcu_core.ld => nodemcu_rodata.ld} | 13 ++++-----
 sdk/esp32-esp-idf                             |  2 +-
 5 files changed, 43 insertions(+), 11 deletions(-)
 create mode 100644 components/base_nodemcu/Makefile.projbuild
 create mode 100755 components/base_nodemcu/add_rodata_ld.sh
 rename components/base_nodemcu/ld/{nodemcu_core.ld => nodemcu_rodata.ld} (75%)

diff --git a/components/base_nodemcu/Makefile.projbuild b/components/base_nodemcu/Makefile.projbuild
new file mode 100644
index 00000000..e2d8ad64
--- /dev/null
+++ b/components/base_nodemcu/Makefile.projbuild
@@ -0,0 +1,8 @@
+BASE_NODEMCU_DIR:=$(dir $(lastword $(MAKEFILE_LIST)))
+BASE_NODEMCU_BUILD_DIR:=$(BUILD_DIR_BASE)/base_nodemcu
+
+$(BUILD_DIR_BASE)/$(PROJECT_NAME).elf: $(BASE_NODEMCU_BUILD_DIR)/ld_patched
+
+$(BASE_NODEMCU_BUILD_DIR)/ld_patched: $(BUILD_DIR_BASE)/esp32/esp32.project.ld
+	"$(BASE_NODEMCU_DIR)/add_rodata_ld.sh" "$<" "$(BASE_NODEMCU_DIR)/ld/nodemcu_rodata.ld"
+	touch $@
diff --git a/components/base_nodemcu/add_rodata_ld.sh b/components/base_nodemcu/add_rodata_ld.sh
new file mode 100755
index 00000000..599d01e1
--- /dev/null
+++ b/components/base_nodemcu/add_rodata_ld.sh
@@ -0,0 +1,27 @@
+#!/bin/bash
+# syntax: add_rodata_ld.sh /path/to/esp32.project.ld /path/to/snippet_file
+set -eu
+ldfile="$1"
+partial="$2"
+out="${ldfile}.new"
+IFS='
+'
+msg="/* NodeMCU patched */"
+if [[ $(head -n 1 "$ldfile") =~ "$msg" ]]
+then
+  echo "NodeMCU rodata already patched into $(basename $ldfile)"
+  exit 0
+else
+  echo "Patching in NodeMCU rodata into $(basename $ldfile)"
+  echo "$msg" > "$out"
+fi
+
+cat "$ldfile" | while read line
+do
+  if [[ $line =~ "drom0_0_seg" ]]
+  then
+    cat "$partial" >> "$out"
+  fi
+  echo $line >> "$out"
+done
+mv "$out" "$ldfile"
diff --git a/components/base_nodemcu/component.mk b/components/base_nodemcu/component.mk
index f563c84b..e69de29b 100644
--- a/components/base_nodemcu/component.mk
+++ b/components/base_nodemcu/component.mk
@@ -1,4 +0,0 @@
-COMPONENT_ADD_INCLUDEDIRS:=include
-# Note: It appears this component must come lexicographically before esp32
-# in order to get the -T arguments in the right order.
-COMPONENT_ADD_LDFLAGS:=-L $(COMPONENT_PATH)/ld -T nodemcu_core.ld -lbase_nodemcu
diff --git a/components/base_nodemcu/ld/nodemcu_core.ld b/components/base_nodemcu/ld/nodemcu_rodata.ld
similarity index 75%
rename from components/base_nodemcu/ld/nodemcu_core.ld
rename to components/base_nodemcu/ld/nodemcu_rodata.ld
index 303d44b6..50458c44 100644
--- a/components/base_nodemcu/ld/nodemcu_core.ld
+++ b/components/base_nodemcu/ld/nodemcu_rodata.ld
@@ -1,6 +1,7 @@
-SECTIONS {
-  .flash.rodata : ALIGN(4)
-  {
+
+    /* ----- Begin NodeMCU link-time arrays ------- */
+
+    . = ALIGN(4);
     /* Link-time arrays containing the defs for the included modules */
     lua_libs = ABSOLUTE(.);
     KEEP(*(.lua_libs))
@@ -11,6 +12,6 @@ SECTIONS {
     esp_event_cb_table = ABSOLUTE(.);
     KEEP(*(.esp_event_cb_table))
     LONG(0) LONG(0) /* Null-terminate the array */
-  }
-}
-INSERT BEFORE .flash.text
+
+    /* ----- End NodeMCU link-time arrays ------- */
+
diff --git a/sdk/esp32-esp-idf b/sdk/esp32-esp-idf
index 4aa1058e..890a341d 160000
--- a/sdk/esp32-esp-idf
+++ b/sdk/esp32-esp-idf
@@ -1 +1 @@
-Subproject commit 4aa1058e8a8f7f3fb17d9ac1158227ad161f2996
+Subproject commit 890a341db429db03a328035b59ca101a5952d096