Add -instcombine-lower-dbg-declare to hwasan flags.
This is a workaround to improve hwasan reports involving stack
variables.
Bug: 112437883
Test: SANITIZE_TARGET=hwaddress, build and boot
Change-Id: I21ea2fdd2d1f04e2bb9b9847785c00a951030c74
diff --git a/cc/sanitize.go b/cc/sanitize.go
index 2bf051e..25dcafe 100644
--- a/cc/sanitize.go
+++ b/cc/sanitize.go
@@ -39,7 +39,16 @@
hwasanCflags = []string{"-fno-omit-frame-pointer", "-Wno-frame-larger-than=",
"-fsanitize-hwaddress-abi=platform",
- "-fno-experimental-new-pass-manager"}
+ "-fno-experimental-new-pass-manager",
+ // The following improves debug location information
+ // availability at the cost of its accuracy. It increases
+ // the likelihood of a stack variable's frame offset
+ // to be recorded in the debug info, which is important
+ // for the quality of hwasan reports. The downside is a
+ // higher number of "optimized out" stack variables.
+ // b/112437883.
+ "-mllvm", "-instcombine-lower-dbg-declare=0",
+ }
cfiCflags = []string{"-flto", "-fsanitize-cfi-cross-dso",
"-fsanitize-blacklist=external/compiler-rt/lib/cfi/cfi_blacklist.txt"}