[scudo] Tune FuchsiaConfig for RiscV

Reduce `PrimaryRegionSizeLog` to 28U to be compatible with a 38bit user
address space on the fuchsia-riscv platform. `PrimaryGroupSizeLog` is
reduced to 19 to preserve 512 BatchGroups per region.

This change can be tested on Fuchsia with:

```
fx set --auto-dir bringup.riscv64 --with //bundles:boot_tests \
fx build bundles:boot_tests \
fx run-boot-test --args={-s,1} boot-libc-unittests \
--cmdline='--gtest_filter=-*DeathTest*:PthreadGetSet*:ScudoSecondaryTest*'
```
The gtest filter ignores pthread and death tests due to non-scudo
related issues on fuchsia-riscv (ScudoSecondaryTest includes a death
check).

Related Ticket: https://fxbug.dev/125263

Differential Revision: https://reviews.llvm.org/D148475

diff --git a/compiler-rt/lib/scudo/standalone/allocator_config.h b/compiler-rt/lib/scudo/standalone/allocator_config.h
index 6430606..d06f6df 100644 (file)
--- a/compiler-rt/lib/scudo/standalone/allocator_config.h
+++ b/compiler-rt/lib/scudo/standalone/allocator_config.h
@@ -169,8 +169,14 @@ struct FuchsiaConfig {
   static const bool MaySupportMemoryTagging = false;
 
   typedef SizeClassAllocator64<FuchsiaConfig> Primary;
+// Support 39-bit VMA for riscv-64
+#if SCUDO_RISCV64
+  static const uptr PrimaryRegionSizeLog = 28U;
+  static const uptr PrimaryGroupSizeLog = 19U;
+#else
   static const uptr PrimaryRegionSizeLog = 30U;
   static const uptr PrimaryGroupSizeLog = 21U;
+#endif
   typedef u32 PrimaryCompactPtrT;
   static const bool PrimaryEnableRandomOffset = true;
   static const uptr PrimaryMapSizeIncrement = 1UL << 18;

diff --git a/compiler-rt/lib/scudo/standalone/platform.h b/compiler-rt/lib/scudo/standalone/platform.h
index db4217d..aae3b9a 100644 (file)
--- a/compiler-rt/lib/scudo/standalone/platform.h
+++ b/compiler-rt/lib/scudo/standalone/platform.h
@@ -37,6 +37,12 @@
 #define SCUDO_TRUSTY 0
 #endif
 
+#if defined(__riscv) && (__riscv_xlen == 64)
+#define SCUDO_RISCV64 1
+#else
+#define SCUDO_RISCV64 0
+#endif
+
 #if defined(__LP64__)
 #define SCUDO_WORDSIZE 64U
 #else