added the --asm command line option for inspection of the produced assember code (#12699)

5 files changed, 39 insertions, 8 deletions

diff --git a/changelog.md b/changelog.md
index caead21b4..5b2509663 100644
--- a/changelog.md
+++ b/changelog.md
@@ -1,4 +1,4 @@
-# x.x - xxxx-xx-xx
+# 1.2 - xxxx-xx-xx
 
 
 ## Changes affecting backwards compatibility
@@ -77,7 +77,8 @@
 
 - JS target indent is all spaces, instead of mixed spaces and tabs, for
   generated JavaScript.
-
+- The Nim compiler now supports the ``--asm`` command option for easier
+  inspection of the produced assembler code.
 
 
 ## Bugfixes
diff --git a/compiler/commands.nim b/compiler/commands.nim
index b0adaae83..88f6bef57 100644
--- a/compiler/commands.nim
+++ b/compiler/commands.nim
@@ -626,6 +626,8 @@ proc processSwitch*(switch, arg: string, pass: TCmdLinePass, info: TLineInfo;
       conf.implicitIncludes.add findModule(conf, arg, toFullPath(conf, info)).string
   of "listcmd":
     processOnOffSwitchG(conf, {optListCmd}, arg, pass, info)
+  of "asm":
+    processOnOffSwitchG(conf, {optProduceAsm}, arg, pass, info)
   of "genmapping":
     processOnOffSwitchG(conf, {optGenMapping}, arg, pass, info)
   of "os":
diff --git a/compiler/extccomp.nim b/compiler/extccomp.nim
index 9b5d16457..5c63f246b 100644
--- a/compiler/extccomp.nim
+++ b/compiler/extccomp.nim
@@ -48,6 +48,7 @@ type
                          # used on some platforms
     asmStmtFrmt: string, # format of ASM statement
     structStmtFmt: string, # Format for struct statement
+    produceAsm: string,   # Format how to produce assembler listings
     props: TInfoCCProps] # properties of the C compiler
 
 
@@ -58,6 +59,9 @@ type
 template compiler(name, settings: untyped): untyped =
   proc name: TInfoCC {.compileTime.} = settings
 
+const
+  gnuAsmListing = "-Wa,-acdl=$asmfile -g -fverbose-asm -masm=intel"
+
 # GNU C and C++ Compiler
 compiler gcc:
   result = (
@@ -80,6 +84,7 @@ compiler gcc:
     pic: "-fPIC",
     asmStmtFrmt: "asm($1);$n",
     structStmtFmt: "$1 $3 $2 ", # struct|union [packed] $name
+    produceAsm: gnuAsmListing,
     props: {hasSwitchRange, hasComputedGoto, hasCpp, hasGcGuard, hasGnuAsm,
             hasAttribute})
 
@@ -105,6 +110,7 @@ compiler nintendoSwitchGCC:
     pic: "-fPIE",
     asmStmtFrmt: "asm($1);$n",
     structStmtFmt: "$1 $3 $2 ", # struct|union [packed] $name
+    produceAsm: gnuAsmListing,
     props: {hasSwitchRange, hasComputedGoto, hasCpp, hasGcGuard, hasGnuAsm,
             hasAttribute})
 
@@ -151,6 +157,7 @@ compiler vcc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$3$n$1 $2",
+    produceAsm: "/Fa$asmfile",
     props: {hasCpp, hasAssume, hasDeclspec})
 
 compiler clangcl:
@@ -196,6 +203,7 @@ compiler lcc:
     pic: "",
     asmStmtFrmt: "_asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {})
 
 # Borland C Compiler
@@ -220,6 +228,7 @@ compiler bcc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {hasSwitchRange, hasComputedGoto, hasCpp, hasGcGuard,
             hasAttribute})
 
@@ -245,6 +254,7 @@ compiler dmc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$3$n$1 $2",
+    produceAsm: "",
     props: {hasCpp})
 
 # Watcom C Compiler
@@ -269,6 +279,7 @@ compiler wcc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {hasCpp})
 
 # Tiny C Compiler
@@ -293,6 +304,7 @@ compiler tcc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {hasSwitchRange, hasComputedGoto})
 
 # Pelles C Compiler
@@ -318,6 +330,7 @@ compiler pcc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {})
 
 # Your C Compiler
@@ -342,6 +355,7 @@ compiler ucc:
     pic: "",
     asmStmtFrmt: "__asm{$n$1$n}$n",
     structStmtFmt: "$1 $2",
+    produceAsm: "",
     props: {})
 
 const
@@ -572,7 +586,8 @@ proc getLinkerExe(conf: ConfigRef; compiler: TSystemCC): string =
            elif optMixedMode in conf.globalOptions and conf.cmd != cmdCompileToCpp: CC[compiler].cppCompiler
            else: getCompilerExe(conf, compiler, AbsoluteFile"")
 
-proc getCompileCFileCmd*(conf: ConfigRef; cfile: Cfile, isMainFile = false): string =
+proc getCompileCFileCmd*(conf: ConfigRef; cfile: Cfile,
+                         isMainFile = false; produceOutput = false): string =
   var c = conf.cCompiler
   var options = cFileSpecificOptions(conf, cfile.nimname)
   var exe = getConfigVar(conf, c, ".exe")
@@ -614,19 +629,30 @@ proc getCompileCFileCmd*(conf: ConfigRef; cfile: Cfile, isMainFile = false): str
 
   # D files are required by nintendo switch libs for
   # compilation. They are basically a list of all includes.
-  let dfile = objfile.changeFileExt(".d").quoteShell()
+  let dfile = objfile.changeFileExt(".d").quoteShell
 
-  objfile = quoteShell(objfile)
   let cfsh = quoteShell(cf)
   result = quoteShell(compilePattern % [
     "dfile", dfile,
-    "file", cfsh, "objfile", objfile, "options", options,
+    "file", cfsh, "objfile", quoteShell(objfile), "options", options,
     "include", includeCmd, "nim", getPrefixDir(conf).string,
     "lib", conf.libpath.string])
+
+  if optProduceAsm in conf.globalOptions:
+    if CC[conf.cCompiler].produceAsm.len > 0:
+      let asmfile = objfile.changeFileExt(".asm").quoteShell
+      addOpt(result, CC[conf.cCompiler].produceAsm % ["asmfile", asmfile])
+      if produceOutput:
+        rawMessage(conf, hintUserRaw, "Produced assembler here: " & asmfile)
+    else:
+      if produceOutput:
+        rawMessage(conf, hintUserRaw, "Couldn't produce assembler listing " &
+          "for the selected C compiler: " & CC[conf.cCompiler].name)
+
   add(result, ' ')
   addf(result, CC[c].compileTmpl, [
     "dfile", dfile,
-    "file", cfsh, "objfile", objfile,
+    "file", cfsh, "objfile", quoteShell(objfile),
     "options", options, "include", includeCmd,
     "nim", quoteShell(getPrefixDir(conf)),
     "lib", quoteShell(conf.libpath),
@@ -680,7 +706,7 @@ proc compileCFiles(conf: ConfigRef; list: CfileList, script: var Rope, cmds: var
   for it in list:
     # call the C compiler for the .c file:
     if it.flags.contains(CfileFlag.Cached): continue
-    var compileCmd = getCompileCFileCmd(conf, it, currIdx == list.len - 1)
+    var compileCmd = getCompileCFileCmd(conf, it, currIdx == list.len - 1, produceOutput=true)
     inc currIdx
     if optCompileOnly notin conf.globalOptions:
       add(cmds, compileCmd)
diff --git a/compiler/options.nim b/compiler/options.nim
index 52ba8254a..2da73ec85 100644
--- a/compiler/options.nim
+++ b/compiler/options.nim
@@ -89,6 +89,7 @@ type                          # please make sure we have under 32 options
     optMultiMethods
     optNimV019
     optBenchmarkVM            # Enables cpuTime() in the VM
+    optProduceAsm             # produce assembler code
 
   TGlobalOptions* = set[TGlobalOption]
 
diff --git a/doc/advopt.txt b/doc/advopt.txt
index 5209a0737..fef9f6895 100644
--- a/doc/advopt.txt
+++ b/doc/advopt.txt
@@ -117,6 +117,7 @@ Advanced options:
   --dynlibOverrideAll
                             disables the effects of the dynlib pragma
   --listCmd                 list the commands used to execute external programs
+  --asm                     produce assembler code
   --parallelBuild:0|1|...   perform a parallel build
                             value = number of processors (0 for auto-detect)
   --incremental:on|off      only recompile the changed modules (experimental!)