Title: [293952] trunk/Source/bmalloc
- Revision
- 293952
- Author
- mark....@apple.com
- Date
- 2022-05-07 19:41:37 -0700 (Sat, 07 May 2022)
Log Message
Force PAS_ASSERT to generate different crash sites for each assertion.
https://bugs.webkit.org/show_bug.cgi?id=240209
Reviewed by Yusuke Suzuki.
Clang currently optimizes all crash sites into one in each function. Hence, if we
get a crash address at the 1 crash site, we don't know which failed assertion got
us there. This patch uses an asm statement to force Clang to emit a different
crash site for each assertion.
Benchmarks show that performance is neutral on both Jetstream2 and Speedometer2.
Size-wise, there is some increase. The following is the "size" output on
_javascript_Core on M1:
__TEXT. __DATA __OBJC others dec hex
old 19628032 180224 0 18792448 38600704 24d0000
new 19644416 180224 0 19251200 39075840 2544000
diff 16384 0 0 458752 475136
The increase in the "others" categories are mostly in the String Table, Symbol
Table, and Function Start Addresses. These take up disk space but should not
impact RAM usage unless they are accessed by a a debugger.
* libpas/src/libpas/pas_utils.h:
(pas_assertion_failed):
Modified Paths
Diff
Modified: trunk/Source/bmalloc/ChangeLog (293951 => 293952)
--- trunk/Source/bmalloc/ChangeLog 2022-05-07 23:34:10 UTC (rev 293951)
+++ trunk/Source/bmalloc/ChangeLog 2022-05-08 02:41:37 UTC (rev 293952)
@@ -1,3 +1,33 @@
+2022-05-07 Mark Lam <mark....@apple.com>
+
+ Force PAS_ASSERT to generate different crash sites for each assertion.
+ https://bugs.webkit.org/show_bug.cgi?id=240209
+
+ Reviewed by Yusuke Suzuki.
+
+ Clang currently optimizes all crash sites into one in each function. Hence, if we
+ get a crash address at the 1 crash site, we don't know which failed assertion got
+ us there. This patch uses an asm statement to force Clang to emit a different
+ crash site for each assertion.
+
+ Benchmarks show that performance is neutral on both Jetstream2 and Speedometer2.
+
+ Size-wise, there is some increase. The following is the "size" output on
+ _javascript_Core on M1:
+
+ __TEXT. __DATA __OBJC others dec hex
+ old 19628032 180224 0 18792448 38600704 24d0000
+ new 19644416 180224 0 19251200 39075840 2544000
+
+ diff 16384 0 0 458752 475136
+
+ The increase in the "others" categories are mostly in the String Table, Symbol
+ Table, and Function Start Addresses. These take up disk space but should not
+ impact RAM usage unless they are accessed by a a debugger.
+
+ * libpas/src/libpas/pas_utils.h:
+ (pas_assertion_failed):
+
2022-04-27 Ross Kirsling <rkirsl...@gmail.com>
Unreviewed libpas build fix for PlayStation.
Modified: trunk/Source/bmalloc/libpas/src/libpas/pas_utils.h (293951 => 293952)
--- trunk/Source/bmalloc/libpas/src/libpas/pas_utils.h 2022-05-07 23:34:10 UTC (rev 293951)
+++ trunk/Source/bmalloc/libpas/src/libpas/pas_utils.h 2022-05-08 02:41:37 UTC (rev 293952)
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018-2021 Apple Inc. All rights reserved.
+ * Copyright (c) 2018-2022 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -193,10 +193,10 @@
static PAS_ALWAYS_INLINE PAS_NO_RETURN void pas_assertion_failed(
const char* filename, int line, const char* function, const char* _expression_)
{
- PAS_UNUSED_PARAM(filename);
- PAS_UNUSED_PARAM(line);
- PAS_UNUSED_PARAM(function);
- PAS_UNUSED_PARAM(_expression_);
+#if PAS_COMPILER(GCC) || PAS_COMPILER(CLANG)
+ // Force each assertion crash site to be unique.
+ asm volatile("" : "=r"(filename), "=r"(line), "=r"(function), "=r"(_expression_));
+#endif
__builtin_trap();
}
#endif /* PAS_ENABLE_TESTING -> so end of !PAS_ENABLE_TESTING */
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