[lld] 745eb02 - [LLD] [MinGW] Implement the --no-seh flag
Martin Storsjö via llvm-commits
llvm-commits at lists.llvm.org
Tue Jul 28 11:08:46 PDT 2020
Author: Martin Storsjö
Date: 2020-07-28T21:08:37+03:00
New Revision: 745eb02496b515cc8292dd7f9d7f0db43e162013
URL: https://github.com/llvm/llvm-project/commit/745eb02496b515cc8292dd7f9d7f0db43e162013
DIFF: https://github.com/llvm/llvm-project/commit/745eb02496b515cc8292dd7f9d7f0db43e162013.diff
LOG: [LLD] [MinGW] Implement the --no-seh flag
Previously this flag was just ignored. If set, set the
IMAGE_DLL_CHARACTERISTICS_NO_SEH bit, regardless of the normal safeSEH
machinery.
In mingw configurations, the safeSEH bit might not be set in e.g. object
files built from handwritten assembly, making it impossible to use the
normal safeseh flag. As mingw setups don't generally use SEH on 32 bit
x86 at all, it should be fine to set that flag bit though - hook up
the existing GNU ld flag for controlling that.
Differential Revision: https://reviews.llvm.org/D84701
Added:
lld/test/COFF/noseh.s
Modified:
lld/COFF/Config.h
lld/COFF/Driver.cpp
lld/COFF/Options.td
lld/COFF/Writer.cpp
lld/MinGW/Driver.cpp
lld/MinGW/Options.td
lld/test/MinGW/driver.test
Removed:
################################################################################
diff --git a/lld/COFF/Config.h b/lld/COFF/Config.h
index 72d826b8bd17..7c439176f3a4 100644
--- a/lld/COFF/Config.h
+++ b/lld/COFF/Config.h
@@ -140,6 +140,7 @@ struct Configuration {
bool safeSEH = false;
Symbol *sehTable = nullptr;
Symbol *sehCount = nullptr;
+ bool noSEH = false;
// Used for /opt:lldlto=N
unsigned ltoo = 2;
diff --git a/lld/COFF/Driver.cpp b/lld/COFF/Driver.cpp
index 7372505bb616..9ceccef86779 100644
--- a/lld/COFF/Driver.cpp
+++ b/lld/COFF/Driver.cpp
@@ -1700,9 +1700,10 @@ void LinkerDriver::link(ArrayRef<const char *> argsArr) {
config->wordsize = config->is64() ? 8 : 4;
// Handle /safeseh, x86 only, on by default, except for mingw.
- if (config->machine == I386 &&
- args.hasFlag(OPT_safeseh, OPT_safeseh_no, !config->mingw))
- config->safeSEH = true;
+ if (config->machine == I386) {
+ config->safeSEH = args.hasFlag(OPT_safeseh, OPT_safeseh_no, !config->mingw);
+ config->noSEH = args.hasArg(OPT_noseh);
+ }
// Handle /functionpadmin
for (auto *arg : args.filtered(OPT_functionpadmin, OPT_functionpadmin_opt))
diff --git a/lld/COFF/Options.td b/lld/COFF/Options.td
index 212879e1d60b..087d53b5d2dd 100644
--- a/lld/COFF/Options.td
+++ b/lld/COFF/Options.td
@@ -204,6 +204,7 @@ def include_optional : Joined<["/", "-", "/?", "-?"], "includeoptional:">,
HelpText<"Add symbol as undefined, but allow it to remain undefined">;
def kill_at : F<"kill-at">;
def lldmingw : F<"lldmingw">;
+def noseh : F<"noseh">;
def output_def : Joined<["/", "-", "/?", "-?"], "output-def:">;
def pdb_source_path : P<"pdbsourcepath",
"Base path used to make relative source file path absolute in PDB">;
diff --git a/lld/COFF/Writer.cpp b/lld/COFF/Writer.cpp
index 3bcc1777f7ac..082de5b8c1d6 100644
--- a/lld/COFF/Writer.cpp
+++ b/lld/COFF/Writer.cpp
@@ -1393,7 +1393,7 @@ template <typename PEHeaderTy> void Writer::writeHeader() {
pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_GUARD_CF;
if (config->integrityCheck)
pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_FORCE_INTEGRITY;
- if (setNoSEHCharacteristic)
+ if (setNoSEHCharacteristic || config->noSEH)
pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_NO_SEH;
if (config->terminalServerAware)
pe->DLLCharacteristics |= IMAGE_DLL_CHARACTERISTICS_TERMINAL_SERVER_AWARE;
diff --git a/lld/MinGW/Driver.cpp b/lld/MinGW/Driver.cpp
index f33b5e19502c..d60765c70c09 100644
--- a/lld/MinGW/Driver.cpp
+++ b/lld/MinGW/Driver.cpp
@@ -288,6 +288,8 @@ bool mingw::link(ArrayRef<const char *> argsArr, bool canExitEarly,
add("-kill-at");
if (args.hasArg(OPT_appcontainer))
add("-appcontainer");
+ if (args.hasArg(OPT_no_seh))
+ add("-noseh");
if (args.getLastArgValue(OPT_m) != "thumb2pe" &&
args.getLastArgValue(OPT_m) != "arm64pe" && !args.hasArg(OPT_dynamicbase))
diff --git a/lld/MinGW/Options.td b/lld/MinGW/Options.td
index 3281951dc89d..fe4416660050 100644
--- a/lld/MinGW/Options.td
+++ b/lld/MinGW/Options.td
@@ -56,6 +56,7 @@ defm minor_subsystem_version: EqLong<"minor-subsystem-version",
"Set the OS and subsystem minor version">;
def no_insert_timestamp: F<"no-insert-timestamp">,
HelpText<"Don't include PE header timestamp">;
+def no_seh: F<"no-seh">, HelpText<"Set the 'no SEH' flag in the executable">;
def no_whole_archive: F<"no-whole-archive">,
HelpText<"No longer include all object files for following archives">;
def large_address_aware: Flag<["--"], "large-address-aware">,
@@ -111,7 +112,6 @@ def: Flag<["--"], "full-shutdown">;
def: F<"high-entropy-va">;
def: S<"major-image-version">;
def: S<"minor-image-version">;
-def: F<"no-seh">;
def: F<"nxcompat">;
def: F<"pic-executable">;
def: S<"plugin">;
diff --git a/lld/test/COFF/noseh.s b/lld/test/COFF/noseh.s
new file mode 100644
index 000000000000..442952286229
--- /dev/null
+++ b/lld/test/COFF/noseh.s
@@ -0,0 +1,19 @@
+# REQUIRES: x86
+# RUN: llvm-mc -triple i686-w64-mingw32 %s -filetype=obj -o %t.obj
+# RUN: lld-link -lldmingw %t.obj -out:%t.exe -entry:main
+# RUN: llvm-readobj --file-headers %t.exe | FileCheck %s --check-prefix=DEFAULT
+# RUN: lld-link -lldmingw %t.obj -out:%t.noseh.exe -entry:main -noseh
+# RUN: llvm-readobj --file-headers %t.noseh.exe | FileCheck %s --check-prefix=NOSEH
+
+# DEFAULT: Characteristics [
+# DEFAULT-NOT: IMAGE_DLL_CHARACTERISTICS_NO_SEH
+# DEFAULT: ]
+
+# NOSEH: Characteristics [
+# NOSEH: IMAGE_DLL_CHARACTERISTICS_NO_SEH
+# NOSEH: ]
+
+ .text
+ .globl _main
+_main:
+ ret
diff --git a/lld/test/MinGW/driver.test b/lld/test/MinGW/driver.test
index 385822c7e1f7..faac3a0be57d 100644
--- a/lld/test/MinGW/driver.test
+++ b/lld/test/MinGW/driver.test
@@ -256,3 +256,7 @@ RUN: ld.lld -### -m i386pep foo.o -section-alignment 0x2000 | FileCheck -check-p
RUN: ld.lld -### -m i386pep foo.o --section-alignment=0x2000 | FileCheck -check-prefix ALIGN %s
RUN: ld.lld -### -m i386pep foo.o -section-alignment=0x2000 | FileCheck -check-prefix ALIGN %s
ALIGN: -align:0x2000
+
+RUN: ld.lld -### -m i386pe foo.o -no-seh | FileCheck -check-prefix NOSEH %s
+RUN: ld.lld -### -m i386pe foo.o --no-seh | FileCheck -check-prefix NOSEH %s
+NOSEH: -noseh
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