From 44b99a6d5f24afcd8476d0d2701e1ca4ab9b35c1 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 22 Mar 2021 12:24:26 +0100 Subject: exec: Build page-vary-common.c with -fno-lto MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In bbc17caf81f, we used an alias attribute to allow target_page to be declared const, and yet be initialized late. This fails when using LTO with several versions of gcc. The compiler looks through the alias and decides that the const variable is statically initialized to zero, then propagates that zero to many uses of the variable. This can be avoided by compiling one object file with -fno-lto. In this way, any initializer cannot be seen, and the constant propagation does not occur. Since we are certain to have this separate compilation unit, we can drop the alias attribute as well. We simply have differing declarations for target_page in different compilation units. Drop the use of init_target_page, and drop the configure detection for CONFIG_ATTRIBUTE_ALIAS. In order to change the compilation flags for a file with meson, we must use a static_library. This runs into specific_ss, where we would need to create many static_library instances. Fix this by splitting page-vary.c: the page-vary-common.c part is compiled once as a static_library, while the page-vary.c part is left in specific_ss in order to handle the target-specific value of TARGET_PAGE_BITS_MIN. Reported-by: Gavin Shan Signed-off-by: Richard Henderson Message-Id: <20210321211534.2101231-1-richard.henderson@linaro.org> [PMD: Fix typo in subject, split original patch in 3] Signed-off-by: Philippe Mathieu-Daudé Tested-by: Gavin Shan Message-Id: <20210322112427.4045204-4-f4bug@amsat.org> [rth: Update MAINTAINERS] Signed-off-by: Richard Henderson --- include/exec/cpu-all.h | 4 ---- include/exec/page-vary.h | 5 +++++ 2 files changed, 5 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index b0a422c7b6..d76b0b9e02 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -216,11 +216,7 @@ static inline void stl_phys_notdirty(AddressSpace *as, hwaddr addr, uint32_t val #ifdef TARGET_PAGE_BITS_VARY # include "exec/page-vary.h" -#if defined(CONFIG_ATTRIBUTE_ALIAS) || !defined(IN_EXEC_VARY) extern const TargetPageBits target_page; -#else -extern TargetPageBits target_page; -#endif #ifdef CONFIG_DEBUG_TCG #define TARGET_PAGE_BITS ({ assert(target_page.decided); target_page.bits; }) #define TARGET_PAGE_MASK ({ assert(target_page.decided); \ diff --git a/include/exec/page-vary.h b/include/exec/page-vary.h index 799d6310d6..c22a7a742e 100644 --- a/include/exec/page-vary.h +++ b/include/exec/page-vary.h @@ -26,4 +26,9 @@ typedef struct { uint64_t mask; } TargetPageBits; +#ifdef IN_PAGE_VARY +extern bool set_preferred_target_page_bits_common(int bits); +extern void finalize_target_page_bits_common(int min); +#endif + #endif /* EXEC_PAGE_VARY_H */ -- cgit v1.2.3