Merge #207

207: Rejig link.x to include more lables to help the linker lay out the ob… r=thejpster a=therealprof

…jects

Tested with 1.34.0 and 1.38.0 and careful inspection of the linker map
generated on the previously failing
https://github.com/rust-lang/rust/files/3722440/minimal-rust-lld-issue.zip

Closes #188 (I believe)
Closes rust-lang/rust#65391

Signed-off-by: Daniel Egger <daniel@eggers-club.de>

Co-authored-by: Daniel Egger <daniel@eggers-club.de>

cortex-m-rt/link.x.in

@@ -88,29 +88,32 @@ SECTIONS
     *(.text .text.*);
     *(.HardFaultTrampoline);
     *(.HardFault.*);
+    . = ALIGN(4);
+    __etext = .;
   } > FLASH
 
   /* ### .rodata */
-  .rodata : ALIGN(4)
+  .rodata __etext : ALIGN(4)
   {
     *(.rodata .rodata.*);
 
     /* 4-byte align the end (VMA) of this section.
        This is required by LLD to ensure the LMA of the following .data
        section will have the correct alignment. */
     . = ALIGN(4);
+    __erodata = .;
   } > FLASH
 
   /* ## Sections in RAM */
   /* ### .data */
-  .data : ALIGN(4)
+  .data : AT(__erodata) ALIGN(4)
   {
     . = ALIGN(4);
     __sdata = .;
     *(.data .data.*);
     . = ALIGN(4); /* 4-byte align the end (VMA) of this section */
     __edata = .;
-  } > RAM AT > FLASH
+  } > RAM
 
   /* LMA of .data */
   __sidata = LOADADDR(.data);