[PATCH] D116485: [clang][MinGW] Explicitly ignore `-fPIC` & friends

[Markus Böck via Phabricator via cfe-commits]

zero9178 created this revision.
zero9178 added reviewers: mstorsjo, compnerd, mati865.
zero9178 requested review of this revision.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.

GCC on Windows ignores this flag completely [0] which some build systems sadly rely on when compiling for Windows using MinGW. The current behaviour of clang however is to error out as `-fPIC` & friends has no effect on Windows.

This patch instead changes the behaviour for MinGW to ignore the option for the sake of compatibility

Fixes https://github.com/llvm/llvm-project/issues/52947

[0] https://gcc.gnu.org/legacy-ml/gcc-patches/2015-08/msg00836.html


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D116485

Files:
  clang/lib/Driver/ToolChains/CommonArgs.cpp
  clang/lib/Driver/ToolChains/MinGW.cpp
  clang/test/Driver/pic.c
  clang/test/Driver/windows-pic.cpp


Index: clang/test/Driver/windows-pic.cpp
===================================================================
--- clang/test/Driver/windows-pic.cpp
+++ clang/test/Driver/windows-pic.cpp
@@ -16,15 +16,6 @@
 // RUN: %clang -### -target i686-windows-itanium -fPIE -fno-pie %s
 // RUN: %clang -### -target i686-windows-itanium -fpie -fno-pie %s
 
-// RUN: %clang -### -target i686-windows-gnu -fPIC %s 2>&1 | FileCheck -check-prefix CHECK-PIC-ERROR %s
-// RUN: %clang -### -target i686-windows-gnu -fpic %s 2>&1 | FileCheck -check-prefix CHECK-pic-ERROR %s
-// RUN: %clang -### -target i686-windows-gnu -fPIE %s 2>&1 | FileCheck -check-prefix CHECK-PIE-ERROR %s
-// RUN: %clang -### -target i686-windows-gnu -fpie %s 2>&1 | FileCheck -check-prefix CHECK-pie-ERROR %s
-// RUN: %clang -### -target i686-windows-gnu -fPIC -fno-pic %s
-// RUN: %clang -### -target i686-windows-gnu -Fpic -fno-pic %s
-// RUN: %clang -### -target i686-windows-gnu -fPIE -fno-pie %s
-// RUN: %clang -### -target i686-windows-gnu -fpie -fno-pie %s
-
 // RUN: %clang -### -target x86_64-windows -fPIC %s 2>&1 | FileCheck -check-prefix CHECK-PIC-ERROR %s
 // RUN: %clang -### -target x86_64-windows -fpic %s 2>&1 | FileCheck -check-prefix CHECK-pic-ERROR %s
 // RUN: %clang -### -target x86_64-windows -fPIE %s 2>&1 | FileCheck -check-prefix CHECK-PIE-ERROR %s
@@ -43,15 +34,6 @@
 // RUN: %clang -### -target x86_64-windows-itanium -fPIE -fno-pie %s
 // RUN: %clang -### -target x86_64-windows-itanium -fpie -fno-pie %s
 
-// RUN: %clang -### -target x86_64-windows-gnu -fPIC %s 2>&1 | FileCheck -check-prefix CHECK-PIC-ERROR %s
-// RUN: %clang -### -target x86_64-windows-gnu -fpic %s 2>&1 | FileCheck -check-prefix CHECK-pic-ERROR %s
-// RUN: %clang -### -target x86_64-windows-gnu -fPIE %s 2>&1 | FileCheck -check-prefix CHECK-PIE-ERROR %s
-// RUN: %clang -### -target x86_64-windows-gnu -fpie %s 2>&1 | FileCheck -check-prefix CHECK-pie-ERROR %s
-// RUN: %clang -### -target x86_64-windows-gnu -fPIC -fno-pic %s
-// RUN: %clang -### -target x86_64-windows-gnu -Fpic -fno-pic %s
-// RUN: %clang -### -target x86_64-windows-gnu -fPIE -fno-pie %s
-// RUN: %clang -### -target x86_64-windows-gnu -fpie -fno-pie %s
-
 // CHECK-PIC-ERROR: unsupported option '-fPIC' for target '{{.*}}
 // CHECK-pic-ERROR: unsupported option '-fpic' for target '{{.*}}
 // CHECK-PIE-ERROR: unsupported option '-fPIE' for target '{{.*}}
Index: clang/test/Driver/pic.c
===================================================================
--- clang/test/Driver/pic.c
+++ clang/test/Driver/pic.c
@@ -301,3 +301,13 @@
 // RUN:   | FileCheck %s --check-prefix=CHECK-PIC2
 // RUN: %clang -c %s -target aarch64-windows-gnu -### 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=CHECK-PIC2
+//
+// On MinGW, allow specifying -fPIC & friends but ignore them
+// RUN: %clang -fno-PIC -c %s -target x86_64-pc-windows-gnu -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-PIC2
+// RUN: %clang -fPIC -c %s -target i686-pc-windows-gnu -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIC
+// RUN: %clang -fno-PIC -c %s -target aarch64-pc-windows-gnu -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-PIC2
+// RUN: %clang -fPIC -c %s -target armv7-pc-windows-gnu -### 2>&1 \
+// RUN:   | FileCheck %s --check-prefix=CHECK-NO-PIC
Index: clang/lib/Driver/ToolChains/MinGW.cpp
===================================================================
--- clang/lib/Driver/ToolChains/MinGW.cpp
+++ clang/lib/Driver/ToolChains/MinGW.cpp
@@ -487,8 +487,7 @@
 }
 
 bool toolchains::MinGW::isPICDefaultForced() const {
-  return getArch() == llvm::Triple::x86_64 ||
-         getArch() == llvm::Triple::aarch64;
+  return true;
 }
 
 llvm::ExceptionHandling
Index: clang/lib/Driver/ToolChains/CommonArgs.cpp
===================================================================
--- clang/lib/Driver/ToolChains/CommonArgs.cpp
+++ clang/lib/Driver/ToolChains/CommonArgs.cpp
@@ -1186,10 +1186,9 @@
                                     options::OPT_fpic, options::OPT_fno_pic,
                                     options::OPT_fPIE, options::OPT_fno_PIE,
                                     options::OPT_fpie, options::OPT_fno_pie);
-  if (Triple.isOSWindows() && LastPICArg &&
-      LastPICArg ==
-          Args.getLastArg(options::OPT_fPIC, options::OPT_fpic,
-                          options::OPT_fPIE, options::OPT_fpie)) {
+  if (Triple.isOSWindows() && !Triple.isOSCygMing() && LastPICArg &&
+      LastPICArg == Args.getLastArg(options::OPT_fPIC, options::OPT_fpic,
+                                    options::OPT_fPIE, options::OPT_fpie)) {
     ToolChain.getDriver().Diag(diag::err_drv_unsupported_opt_for_target)
         << LastPICArg->getSpelling() << Triple.str();
     if (Triple.getArch() == llvm::Triple::x86_64)


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