build: remove explicit linker call to libm on macOS

deepak1556 · targos · commit e0dd9aefd644 · 2025-02-10T15:15:03.000+01:00
/usr/lib/libm.tbd is available via libSystem.*.dylib and reexports sanitizer symbols. When building for asan this becomes an issue as the linker will resolve the symbols from the system library rather from libclang_rt.* For V8 that rely on specific version of these symbols that get bundled as part of clang, for ex: https://source.chromium.org/chromium/chromium/src/+/main:v8/src/heap/cppgc/platform.cc;l=93-97 accepting nullptr for shadow_offset in `asan_get_shadow_mapping`, linking to system version that doesn't support this will lead to a crash. Clang driver eventually links with `-lSystem` https://github.com/llvm/llvm-project/blob/e82f93890daefeb38fe2a22ee3db87a89948ec57/clang/lib/Driver/ToolChains/Darwin.cpp#L1628-L1631, this is done after linking the sanitizer libraries which ensures right order of resolution for the symbols. PR-URL: #56901 Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com> Reviewed-By: Chengzhong Wu <legendecas@gmail.com> Reviewed-By: Luigi Pinca <luigipinca@gmail.com> Reviewed-By: Shelley Vohr <shelley.vohr@gmail.com>
diff --git a/deps/brotli/unofficial.gni b/deps/brotli/unofficial.gni
@@ -25,7 +25,7 @@ template("brotli_gn_build") {
     } else if (target_os == "freebsd") {
       defines = [ "OS_FREEBSD" ]
     }
-    if (!is_win) {
+    if (is_linux) {
       libs = [ "m" ]
     }
     if (is_clang || !is_win) {
diff --git a/deps/uv/unofficial.gni b/deps/uv/unofficial.gni
@@ -87,11 +87,11 @@ template("uv_gn_build") {
       ]
     }
     if (is_posix) {
-      libs = [ "m" ]
       ldflags = [ "-pthread" ]
     }
     if (is_linux) {
       libs += [
+        "m",
         "dl",
         "rt",
       ]

Original file line number	Diff line number	Diff line change
`@@ -25,7 +25,7 @@ template("brotli_gn_build") {`
`25`	`25`	`} else if (target_os == "freebsd") {`
`26`	`26`	`defines = [ "OS_FREEBSD" ]`
`27`	`27`	`}`
`28`		`- if (!is_win) {`
	`28`	`+ if (is_linux) {`
`29`	`29`	`libs = [ "m" ]`
`30`	`30`	`}`
`31`	`31`	`if (is_clang \|\| !is_win) {`
Original file line number	Diff line number	Diff line change
`@@ -87,11 +87,11 @@ template("uv_gn_build") {`
`87`	`87`	`]`
`88`	`88`	`}`
`89`	`89`	`if (is_posix) {`
`90`		`- libs = [ "m" ]`
`91`	`90`	`ldflags = [ "-pthread" ]`
`92`	`91`	`}`
`93`	`92`	`if (is_linux) {`
`94`	`93`	`libs += [`
	`94`	`+ "m",`
`95`	`95`	`"dl",`
`96`	`96`	`"rt",`
`97`	`97`	`]`