https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91922
Bug ID: 91922
Summary: #pragma pack(push,4) does not align element on 32 bit
boundary properly
Product: gcc
Version: 6.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: slightbody at ledroadwaylighting dot com
Target Milestone: ---
Created attachment 46958
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46958&action=edit
c source
The attached small main.c results in a Hard Fault on the line *p=x; when
compiled for the Cortex M0+ processor. The u32thing element of the structure
should be aligned on a 32bit boundary in memory due to the #pragma pack(push,4)
statement, but it is not.
It appears the compiler may be being confused by the pack(1) directive later in
the structure.
Compile line:
"D:\Atmel\Studio\7.0\toolchain\arm\arm-gnu-toolchain\bin\arm-none-eabi-gcc.exe"
-x c -mthumb -D__SAMD21G18A__ -DNDEBUG
-I"D:\Atmel\Studio\7.0\Packs\arm\cmsis\5.0.1\CMSIS\Include"
-I"D:\Atmel\Studio\7.0\Packs\atmel\SAMD21_DFP\1.3.304\samd21a\include" -Os
-ffunction-sections -mlong-calls -Wall -mcpu=cortex-m0plus -c -std=gnu99 -MD
-MP -MF "main.d" -MT"main.d" -MT"main.o" -o "main.o" ".././main.c"
Snip of .map file (one_v) should be on a 32 bit aligned address:
*(COMMON)
COMMON 0x20000450 0xa main.o
0x20000450 two
0x20000454 abc
0x20000455 one_v
