Revert "[hwasan] Add fixed_shadow_base flag" (#95435)

fmayer · web-flow · commit 12f77e811b49 · 2024-06-13T10:07:49.000-07:00
Reverts #73980 This broke static hwasan binaries in Android, for some reason the fixed_shadow_base branch gets taken
diff --git a/compiler-rt/lib/hwasan/hwasan_flags.inc b/compiler-rt/lib/hwasan/hwasan_flags.inc
@@ -84,10 +84,3 @@ HWASAN_FLAG(bool, malloc_bisect_dump, false,
 // are untagged before the call.
 HWASAN_FLAG(bool, fail_without_syscall_abi, true,
             "Exit if fail to request relaxed syscall ABI.")
-
-HWASAN_FLAG(
-    uptr, fixed_shadow_base, -1,
-    "If not -1, HWASan will attempt to allocate the shadow at this address, "
-    "instead of choosing one dynamically."
-    "Tip: this can be combined with the compiler option, "
-    "-hwasan-mapping-offset, to optimize the instrumentation.")
diff --git a/compiler-rt/lib/hwasan/hwasan_linux.cpp b/compiler-rt/lib/hwasan/hwasan_linux.cpp
@@ -106,12 +106,8 @@ static uptr GetHighMemEnd() {
 }
 
 static void InitializeShadowBaseAddress(uptr shadow_size_bytes) {
-  if (flags()->fixed_shadow_base != (uptr)-1) {
-    __hwasan_shadow_memory_dynamic_address = flags()->fixed_shadow_base;
-  } else {
-    __hwasan_shadow_memory_dynamic_address =
-        FindDynamicShadowStart(shadow_size_bytes);
-  }
+  __hwasan_shadow_memory_dynamic_address =
+      FindDynamicShadowStart(shadow_size_bytes);
 }
 
 static void MaybeDieIfNoTaggingAbi(const char *message) {
diff --git a/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c b/compiler-rt/test/hwasan/TestCases/Linux/fixed-shadow.c

Original file line number	Diff line number	Diff line change
`@@ -106,12 +106,8 @@ static uptr GetHighMemEnd() {`
`106`	`106`	`}`
`107`	`107`
`108`	`108`	`static void InitializeShadowBaseAddress(uptr shadow_size_bytes) {`
`109`		`- if (flags()->fixed_shadow_base != (uptr)-1) {`
`110`		`- __hwasan_shadow_memory_dynamic_address = flags()->fixed_shadow_base;`
`111`		`- } else {`
`112`		`- __hwasan_shadow_memory_dynamic_address =`
`113`		`- FindDynamicShadowStart(shadow_size_bytes);`
`114`		`- }`
	`109`	`+ __hwasan_shadow_memory_dynamic_address =`
	`110`	`+ FindDynamicShadowStart(shadow_size_bytes);`
`115`	`111`	`}`
`116`	`112`
`117`	`113`	`static void MaybeDieIfNoTaggingAbi(const char *message) {`