diff options
Diffstat (limited to 'lib/sanitizer_common/sanitizer_coverage_win_sections.cc')
| -rw-r--r-- | lib/sanitizer_common/sanitizer_coverage_win_sections.cc | 53 |
1 files changed, 47 insertions, 6 deletions
diff --git a/lib/sanitizer_common/sanitizer_coverage_win_sections.cc b/lib/sanitizer_common/sanitizer_coverage_win_sections.cc index 4b0bbf1ed1e5..108f76effeeb 100644 --- a/lib/sanitizer_common/sanitizer_coverage_win_sections.cc +++ b/lib/sanitizer_common/sanitizer_coverage_win_sections.cc @@ -7,16 +7,57 @@ // //===----------------------------------------------------------------------===// // -// This file defines delimiters for Sanitizer Coverage's section. +// This file defines delimiters for Sanitizer Coverage's section. It contains +// Windows specific tricks to coax the linker into giving us the start and stop +// addresses of a section, as ELF linkers can do, to get the size of certain +// arrays. According to https://msdn.microsoft.com/en-us/library/7977wcck.aspx +// sections with the same name before "$" are sorted alphabetically by the +// string that comes after "$" and merged into one section. We take advantage +// of this by putting data we want the size of into the middle (M) of a section, +// by using the letter "M" after "$". We get the start of this data (ie: +// __start_section_name) by making the start variable come at the start of the +// section (using the letter A after "$"). We do the same to get the end of the +// data by using the letter "Z" after "$" to make the end variable come after +// the data. Note that because of our technique the address of the start +// variable is actually the address of data that comes before our middle +// section. We also need to prevent the linker from adding any padding. Each +// technique we use for this is explained in the comments below. //===----------------------------------------------------------------------===// #include "sanitizer_platform.h" #if SANITIZER_WINDOWS #include <stdint.h> -#pragma section(".SCOV$A", read, write) // NOLINT -#pragma section(".SCOV$Z", read, write) // NOLINT extern "C" { -__declspec(allocate(".SCOV$A")) uint32_t __start___sancov_guards = 0; -__declspec(allocate(".SCOV$Z")) uint32_t __stop___sancov_guards = 0; +// The Guard array and counter array should both be merged into the .data +// section to reduce the number of PE sections However, because PCTable is +// constant it should be merged with the .rdata section. +#pragma section(".SCOV$GA", read, write) // NOLINT +// Use align(1) to avoid adding any padding that will mess up clients trying to +// determine the start and end of the array. +__declspec(allocate(".SCOV$GA")) __declspec(align(1)) uint64_t + __start___sancov_guards = 0; +#pragma section(".SCOV$GZ", read, write) // NOLINT +__declspec(allocate(".SCOV$GZ")) __declspec(align(1)) uint64_t + __stop___sancov_guards = 0; + +#pragma section(".SCOV$CA", read, write) // NOLINT +__declspec(allocate(".SCOV$CA")) __declspec(align(1)) uint64_t + __start___sancov_cntrs = 0; +#pragma section(".SCOV$CZ", read, write) // NOLINT +__declspec(allocate(".SCOV$CZ")) __declspec(align(1)) uint64_t + __stop___sancov_cntrs = 0; + +#pragma comment(linker, "/MERGE:.SCOV=.data") + +// Use uint64_t so there won't be any issues if the linker tries to word align +// the pc array. +#pragma section(".SCOVP$A", read) // NOLINT +__declspec(allocate(".SCOVP$A")) __declspec(align(1)) uint64_t + __start___sancov_pcs = 0; +#pragma section(".SCOVP$Z", read) // NOLINT +__declspec(allocate(".SCOVP$Z")) __declspec(align(1)) uint64_t + __stop___sancov_pcs = 0; + +#pragma comment(linker, "/MERGE:.SCOVP=.rdata") } -#endif // SANITIZER_WINDOWS +#endif // SANITIZER_WINDOWS |