Add an assembly snippet for `mips_option_tests' to verify that
instructions executed on the target board may freely access executable
sections.
Depending on target board's execution environment, which may map
executable pages with the Read Inhibit (RI) bit set in the TLB or may
have a split SPRAM memory which directs instruction fetch and data read
accesses to different parts of the memory, code may or may not be able
to access parts of executable sections as data.
Therefore verify that data reads from executable sections both complete
successfully and that correct data is retrieved (though with a small
probability of a false positive). Use MIPS16 execution to access data
required as the `-mcode-readable=yes' option only affects MIPS16 code
generation anyway, which however simplifies handling a little bit as
PC-relative addressing can be used to calculate the location of data
required, avoiding any issues if using the PIE or PIC code generation
model.
Use the BREAK instruction to trap on a comparison check failure so that
the effect is immediate and there is no need to wait for the test
program to time out; resort to an infinite loop though in the unlikely
event a Bp exception handler resumes execution beyond the trapping
instruction.
NB there is no need to explicitly align data emitted with the `.word'
pseudo-op, which is self-aligning.
gcc/testsuite/
* gcc.target/mips/mips.exp (mips_option_tests): Add
`-mcode-readable=yes' array element.
---
OK to apply?
Maciej
gcc-mips-test-option-tests-mcode-readable-yes.diff
Index: gcc/gcc/testsuite/gcc.target/mips/mips.exp
===================================================================
--- gcc.orig/gcc/testsuite/gcc.target/mips/mips.exp 2016-11-09
18:56:48.283197623 +0000
+++ gcc/gcc/testsuite/gcc.target/mips/mips.exp 2016-11-11 08:49:53.345912380
+0000
@@ -401,6 +401,27 @@ set mips_option_tests(-mdspr2) {
.set dspr2
prepend $2,$3,11
}
+set mips_option_tests(-mcode-readable=yes) {
+ move $2,$31
+ bal 1f
+ .set mips16
+ la $3,0f
+ lw $3,($3)
+ jr $31
+0:
+ .word 0xfacebead
+ .set nomips16
+ .align 2
+1:
+ ori $3,$31,1
+ jalr $3
+ li $4,0xfacebead
+ beq $3,$4,2f
+ break
+ b .
+2:
+ move $31,$2
+}
# Canonicalize command-line option OPTION.
proc mips_canonicalize_option { option } {
