[libFuzzer] Refactor GetNextInstructionPc/GetPreviousInstructionPc
Port the change to compiler-rt/lib/fuzzer/FuzzerTracePC.cpp .
Update RISCV to use PC-2: this is coarse (C extension may be disabled) but
sufficient for pure symbolization purpose.
The commit is separate from D120362 so that bisecting/reverting is easier.
GitOrigin-RevId: fc0bd3c2cee929ffbd75b5cca486f4c77f7d5c59
diff --git a/FuzzerTracePC.cpp b/FuzzerTracePC.cpp
index af8d1ce..f12f7aa 100644
--- a/FuzzerTracePC.cpp
+++ b/FuzzerTracePC.cpp
@@ -133,13 +133,14 @@
// so we return (pc-2) in that case in order to be safe.
// For A32 mode we return (pc-4) because all instructions are 32 bit long.
return (PC - 3) & (~1);
-#elif defined(__powerpc__) || defined(__powerpc64__) || defined(__aarch64__)
- // PCs are always 4 byte aligned.
- return PC - 4;
#elif defined(__sparc__) || defined(__mips__)
return PC - 8;
-#else
+#elif defined(__riscv__)
+ return PC - 2;
+#elif defined(__i386__) || defined(__x86_64__) || defined(_M_IX86) || defined(_M_X64)
return PC - 1;
+#else
+ return PC - 4;
#endif
}
